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FLORIDA
MUSEUM OF
NATURAL HISTORY
THE COMPARATIVE ECOLOGY OF BOBCAT,
BLACK BEAR, AND FLORIDA PANTHER
IN SOUTH FLORIDA
David Steffen Maehr
Volume 40, No. 1, pp. 1-176
1997
UNIVERSITY OF FLORIDA
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Publication date: October 1, 1997
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Frontispiece: Female Florida panther #32 treed by hounds in a laurel oak at the site of her first capture on the Florida Panther
National Wildlife Refuge in central Collier County, 3 February 1989. Photograph by David S. Maehr.
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THE COMPARATIVE ECOLOGY OF BOBCAT, BLACK
BEAR, AND FLORIDA PANTHER IN SOUTH FLORIDA
David Steffen Maehr'
ABSTRACT
Comparisons of food habits, habitat use, and movements revealed a low probability for competitive
interactions among bobcat (Lynx rufis), Florida panther (Puma concolor cory), and black bear (Ursus
americanus) in South Florida. All three species preferred upland forests but consumed different foods and
utilized the landscape in ways that resulted in ecological separation. Further, panthers exhibited crepuscular
activity whereas black bear were predominantly diurnal. Diet, movements, and reproduction varied
seasonally among species.
Subadults of all three species demonstrated extensive disposal abilities, but only male black bears
were documented to have crossed the Caloosahatchee River, a potential landscape barrier that may restrict
effective dispersal northward in bobcats and panthers.
Because bobcat and black bear in South Florida occur at relatively high densities, anthropogenic
changes to the landscape and sea level rise will affect them less severely than panther. The problems
associated with the habitation of a naturally fragmented and patchy forest are exacerbated by the conversion
of productive habitat types to types that are avoided. Another factor that threaten the stability of ecological
relations among this carnivore community is the range expansion of the coyote (Canis latrans) into South
Florida. This canid is known to exhibit intferfence competition with bobcats, black bears, and panthers in
other parts of North America. The diet of the coyote in Florida may overlap with the dies ofe there r native
carnivores by at least 38 percent and as much as 64 percent.
The highest concentrations of black bean and panthers in South Florida coincide with an extensive
forest, a landscape feature that accounts for only a small proportion of public land. Increasing forest
fragmentation from the Sarasota area southeastward suggests that most public lands are relatively
unimportant to the two larger species. Because the demographics of even the smallest of these populations
(panther) are shown to be typical of healthy populations, creative management, such as flexible reserve
boundaries and the enlistment of private property owners in conservation efforts, may be of more immediate
value than symptom-oriented management practices such as genetic introgression.
RESUMO
Comparag es do hibito alimentar, uso de habitat, e movimentos revelaram uma baixa probabilidade
de interaOes competitivas entire o "bobcat"(Lynx rufus), o puma americano (Puma concolor coryi), o urso
negro (Ursus americanus) no sul da Florida. As tries espcies preferiram florestas de terras altas ma
consumiram diferentes tipos de alimento e utilizaram o espago de uma modo que resultou em separagio
ecol6gica. 0 puma apresentou atividades crepusculares, enquanto que o urso negro foi predominntement
de hibito diurno. Dieta, movimentos, e reprodugio variaram sasonalmente entire as esp6cies. Subadultos das
' he author i Asistant Promfsor, Forty, Coege ofAgricuM 205omn Poe Coopr Bulig Unity ofKmucy, Lei
KY 40546073 U.SA
MAEHR, D.S. 1997. The comparative ecology of bobcat, black bear, and Florida panther in South Florida.
Bull. Florida Mus. Nat. Hist 40(1):1-176.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
tres esp6cies demonstraram grande habilidade de dispersal, mas somente machos do uno negro foram
documentados atravessando o Rio Caloosahatchee, uma potential barreir na paisagmn que talvez limited
uma dispeslo efetiva parn o norte em "bobcats"e pumas.
Uma vez que no sul da Florida "bobcats" e urss negros ocorrem em densidades relativamente altas,
mudancas antr6picas na paisagem, somadas a urn possivel aumento no nivel das mards, irio afeta-lo de
maneira menos sever do que o puma. Os problems associado cam a habitaio de ares naturament.
fiagmentadas e florestas isoladas so exacerbados pela converslo de habitats produtives para tipa habitat
que sio evitados por eas esp6cies. Outro fator que ameaga a estabilidade das relaq8e ecol6gicas etre ta
comunidade d carnivorous 6 a expansdo da distribuigio do coyote (Canis latrans) que vem oconando no sul
da Florida. t sabido que ese canideo compete com "bobcats" urso e pumas em outras parties da Amrica do
Norte. A dieta do coyote na Flbrida talvez se sobreponha com a dieta desses tres carnivorom natives em pelo
menos 38% podendo chegar at6 a 64%.
Locais de alta concentracio de ursos negros e pumas no sul da Fl6rida coincidem com florestas
exten9as, uma caracteristica de paisagem que ocorrem em pequena proporao em terras pdblicas. O aumento
da fragmentagio das florestas na irea de Sarasota em diregio su susugere que a maioria das terras p6blicas
sio relativamente menos importantes para as duas esp6cies maiores. Devido aos fatores demogrificos at6
para a menor dessas populaq6es (puma) se mostrarem ser tipicos de populaqs sadias, o manejo criativo,
tais como limited mais flexiveis das reserves, e o cadastramento de proprietrios d teras privadas em
esforgos conservacionistas, talvez tenham valor mais imediato do que priticas de manejo sintomitics, como
por exemplo introgressio genetic.
TABLE OF CONTENTS
Acknowledgements.................................................................................................................................... 3
1. Introduction........................................................................................................................................... 4
Overview of Carnivore Community Studies..................................................... ................... 5
Study Area....................................................................................................................................... 9
Summary of Previous Large Carnivore Work in Florida............................................................ 13
General Methodology ..................................................................................................................... 18
2. Dietary Overlap..................................................................................................................................... 21
Methods............................... ................................................................................................. 21
Results and Discussion.................................................................................................................... 22
Species Comparison ...................................................................................................................... 27
3. Habitat Use Among South Florida's Large Mammalian Carnivores................................................. 35
Methods............................. ........................................... ............................... ........ 36
Results and Discussion.................................................................................................................... 38
4. Habitat Pattern around Florida Panther Natal Dens and Black Bear Winter Dens............................. 60
Methods........................................................................................................................................... 60
Results and Discussion.................................................................................................................... 61
Influence of Roads.......................................................................................................................... 65
5. Home Range, Activity, and Land Tenure............................................................................................ 73
Methods........................................................................................................................................... 74
Results and Discussion.................................................................................................................... 75
Seasonal Effects .............................................................................................................................. 76
Home Range Fidelity and Replacement............................................................. ...................... 81
Overlap W within and Among Species.............................................................................................. 83
6. Dispersal Characteristics....................................................................................................................... 117
Methods........................................................................................................................................... 118
Results and Discussion.................................................................................................................... 118
Adults and Disp rs Compared............................................................................. 20
7. Synthesis and Conclusions.................................................................................................................... 144
The Return of W ild Canids to Florida............................................................................................ 147
A Longer Range View .................................................................................................................... 150
Literature Cited ............................................ ......................................................................................... 161
Appendix A............................................................................................................................................. 173
Appendix B............................................................................................................................................... 175
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
ACKNOWLEDGEMENTS
Many people have contributed to our current understanding of large carnivore ecology in South
Florida. Notable in this endeavor are E.D. Land, Todd Logan, J.C. Roof J.W. McCown, O.L Bas, and
J.N. Layne. R.T. McBride, and frequently his sons Rocky and Rowdy, linked us with study animals and
maintained long-term contact with many of them. I am also grateful for the opportunity to have worked with
M.E. Roelke, C. Glass, M.Lann, T. Ruth, S. Citino, and especially J. Lanier, all of whom helped to look
after anesthetized bobcats and panthers. J. Kappes, R. Bell, and P. Barnoffwere important field assistants
who lent their unique personalities to the project. Diane Maehr, C. Maehr, and E. Maehr were special
assistants during several captures ofbobcats, panthers and black bears.
I thank the Florida Game and Fresh Water Fish Commission for allowing me to be a part of its
celebrated research efforts on the Florida panther and for consistent funding of this important field work.
The U.S. Fish and Wildlife Service, Florida Department of Environmental Protection, National Park Service,
and the Seminole Indian Tribe facilitated access to their vast holdings of publicly owned land. Of equal, if
not greater, importance was the access to private properties and the assistance of their managers and owners
including B. Lester, B.H. Griffin, E. Carlson, E. English, L Gable, B. Collier, M. Scofield, J. Fitzpatrick, T.
Baker, J. McDaniel, D. Pylant, M. Ramsey, J. Hendrie, E. and J. Smoak, J. Hilliard, and J. Billie.
M. Sunquist and J. Eisenberg challenged me with provocative ideas and helped draw new ideas out of
me. I am especially indebted to LD. Harris who was one of my first acquaintances in Florida and who
continues to be a friend and my most ardent supporter. His visions of the way things were and the way they
should be have benefitted many ecological disciplines and everyone he has worked with. His abilities to
compel, cajole, and convince are equally matched by his willingness to listen, learn, and change.
I thank G. Tanner and S. Humphrey, and Bulletin editors J. Eisenberg, R. Bryant, and R. Franz for
facilitating the production of this publication. Reviewers J. Seidensticker and H. Quigley provided valuable
comments that improved the manuscript. Others who have helped me along this path in meaningful ways
include T. "Birdman" Hoctor, K. Deagan, J. Cox, F. Percival, P. Hall, M. Moulton, C. Arnold, E. Hellgre,
C. Abercrombie, J. Mullahey, E. Jacobson, W. Kitchens, F. Mazzotti, and J. "Loquacious" Schotemeyer.
Publication of this bulletin was made possible through the generous contributions of Scott Harris,
Naples, Florida, a grant from the Turner Foundation, Inc., by way of the Florida Stewardship Foundation,
and the University of Florida. This is journal series number R-05638 of the Florida Agricultural Experiment
Station. It is connected with a project of the Kentucky Agricultural Station (No. 97-09-62) and is published
with the approval of the director.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
1. INTRODUCTION
The terrestrial mammalian carnivore communities of pre-European temperate
North America consisted of 35 species belonging to five families (Table 1.1). The
prehistoric distribution, abundance, and associations of these species were a
function of the interaction of climate, plant succession, competitors, and prey
demographics (Harris 1988), factors that are all directly linked to geography and
productivity of the landscape (Harris 1984:11-23; Zonneveld 1990). Although
primitive humans (Homo sapiens) were a significant competitor with and predator
on many of these species, post-Columbian humans have been much more effective
than their predecessors in reducing native carnivore abundance and diversity
throughout the continent (Diamond 1992). Modern local extinctions of large
carnivores and a relative overabundance of medium-sized mammals throughout the
southeastern United States have resulted from anthropogenic influences that
include species introductions, over-harvest, and habitat fragmentation.
The study of large carnivores in North America during the 20th century has
evolved from a predator control philosophy to an ecological paradigm that includes
carnivores as integral components of community and landscape processes.
Leopold's (1949) vision of enlightened wolf and landscape management seems to
have become a modern standard for several ecological disciplines. Indeed, special
volumes of Transactions of the North American Wildlife and Natural Resources
Conference (Vol. 56; 1991), Conservation Biology (Vol. 10, No. 4; 1996), and the
Wildlife Society Bulletin (Vol. 24, No. 3; 1996) emphasize the scientific and
popular roles that predators now play in both domestic and international
environmental policy. Restoration of carnivore populations has now replaced
efforts to eradicate them as conservation professionals and the public learn to
accept the value of large, natural areas and the wide-ranging animals that live in
them (Clark et al. 1996; Mech 1996).
Eleven mammalian carnivores existed in post-Pleistocene Florida (Table 1.1).
The red wolf (Canis rufus) has been extirpated due to overharvest and habitat
alterations (Nowak 1991; Robson 1992), and the Caribbean monk seal (Monachus
tropicalis) is extinct primarily because of overharvest (Wing 1992). The
remaining species represent a nearly intact assemblage that has persisted to the
present, despite Florida's quickly growing human population. It is a testimony to
the difficulties of settling a wet, hot, and flat landscape that three out of four large
(>10 kg) terrestrial carnivores persist in South Florida. It has been only 70 years
since highways were built to bisect this previously impenetrable wilderness (Carter
1974), and there is nowhere else in eastern North America where bobcats (Lynx
rufus), black bears (Ursus americanus), and Florida panthers (Puma concolor
coryi) continue to coexist.
Although the three large carnivores native to South Florida have been studied
previously, none of the ecological studies exceeds more than a few years. Further,
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
no analyses have examined them as an interacting community that inhabits the
same landscape. Therefore, the objectives of this study were as follows:
1) Describe the spatial dynamics and habitat requirements of resident adult
panthers, black bears, and bobcats in a rapidly developing South
Florida landscape;
2) Analyze, compare, and contrast the use of space of resident carnivores
with that of dispersing subadults; and
3) Discuss the long-term prospects for the large carnivore community in
South Florida with respect to landscape and biotic changes that are
under way.
Overview of Carnivore Community Studies
Because of the difficulties in studying large carnivores, investigations of
multi-species predator communities are sparse relative to studies of individual
species. In addition, few detailed studies of multiple-species carnivore assemblages
have occurred in settings conducive to direct observation. Schaller's (1972) study
of the African lion (Panthera leo) included detailed accounts of interactions among
five Serengeti predators. Competition appeared to be reduced in that community
by differences in habitat use, temporal separation, prey preferences, prey size, and
hunting methods. Kruuk and Turner (1967), Bertram (1979), and Hanby and
Bygott (1979) observed similar patterns among lion, leopard (P. pardus), cheetah
(Acinonyxjubatus), and wild dog (Lycaon pictus) in the Serengeti.
Mills (1984) found that the four large predators in the Kalahari coexisted by
reducing competition. Although lion and spotted hyena (Crocuta crocuta) were
mostly nocturnal and fed on similar species, they targeted different sex and age
classes. Cheetah and leopard, on the other hand, exhibited temporal habitat
separation and the leopard had a more varied diet than its likely competitors. On
the other hand, in the Kalahari Gemsbok National Park, extremely high dietary
overlap among the lion, leopard, cheetah, and spotted hyena was caused by
relatively low prey species diversity (Eloff 1973). Mills and Mills (1982) found
that the brown hyena (Hyaena brunnea) and spotted hyena became direct
competitors only when both were forced to rely on scavenging. Inverse relations in
abundance have been observed or inferred between pairs of Old World predators.
Myers (1977) found that cheetah were more abundant where spotted hyena were
absent or scarce. When both species competed for Thompson's gazelle (Gazella
thomsoni), the cheetah was at a disadvantage and usually declined in number.
Seidensticker (1976) found that tiger (Panthera tigris) and leopard in Nepal
exhibited nearly total ecological separation from each other by consuming
different-sized prey, by using different habitat, and by exhibiting different patterns
of activity. Only where prey were abundant did these two species coexist in similar
habitats. A study of leopard and caracal (Felis caracal) in South Africa showed
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
that these species avoided competition by utilizing mutually exclusive habitat types
(Norton and Lawson 1985).
In South America, direct observations of interactions between species are
nearly impossible due to the dense vegetation that many forest carnivores inhabit.
At the same time, the very environmental conditions that hamper the development
of ethograms, have likely affected the way these species utilize their landscape.
Interestingly, while most studies of carnivore communities in the Old World
tropics inferred several levels of competition among sympatric vertebrate predators,
the opposite appears to be the case in the New World tropics.
Konecny (1989) examined a small carnivore community in Belize that lacked
obvious competitive interactions. Jaguarundi (Fells jaguaroundi), tayra (Eira
barbara), ocelot (Felis pardalis), and margay (Felis weidii) coexisted without
using similar habitats and with little dietary overlap. Puma, jaguar, and ocelot
avoided competition by means of prey size partitioning and habitat specialization
(Schaller and Crawshaw 1980; Rabinowitz and Nottingham 1986; Emmons 1987).
Sunquist et al. (1989) found that ocelot, hog-nosed skunk, tayra, grison (Galictis
vittata), and crab-eating fox (Cerdocyon thous) avoided competition in Venezuelan
llanos through diet partitioning.
The importance of the grizzly bear (Ursus arctos) in the sclerophyll
community of western North America was considered sufficient to include its
common name as part of Shelford's (1963) ecological classification of North
America. Its predominance resulted in the virtual exclusion of the black bear. But
through time and coincident with the decline of its larger competitor, the black
bear is now widespread in this part of the grizzly bear's former range. Herrero
(1978) suggested that evolutionary processes resulted in differences in form and
behavior between black bear and brown bear. Larger size, more aggressive
behavior, adaptations for digging, and the inability to climb trees suit the brown
bear to life in more open habitats than the forest-dwelling, tree-climbing less
aggressive black bear. The separation of these species was maintained by historic
patterns of forest cover and the brown bear's dominance over the black bear. In
most cases where overt interactions have been reported, the brown bear was
dominant (Mattson et al. 1992; Ross et al. 1988).
Giant panda (Ailuropoda melanoleuca) and Asiatic black bear (Ursus
thibetanus) exhibit a high degree of spatial overlap and similarity in size and form,
yet exhibit divergent food habits and feeding strategies (Schaller et al. 1989).
Despite having similar digestive systems, the giant panda is a food specialist while
the Asiatic black K-ar is a food generalist. No competitive interactions between
these species have been reported. Johnson et al. (1988) reported that red panda
(Ailurus fulgens) and giant panda overlapped in space but have evolved very
different energetic and behavioral strategies that allow them to utilize different
plant parts.
Sympatric carnivores throughout the world exhibit a multitude of strategies
for separating themselves in environments of limited resources. When a common
MAEHR: ECOLOGY BOBCAT, BLACK BEAR. PANTHER
resource is utilized by more than one species, co-occurrence is facilitated by
differences in habitat use, and/or activity pattern. These patterns change with size
of prey, size of predator, number of potential competitors (Rosenzweig 1966),
climate, group size, and human influences. Schoener (1974) generalized that
resource partitioning was most often accomplished by means of separation along
habitat dimensions rather than temporal dimensions. However, his review focused
primarily on invertebrates, birds, and small mammals and did not consider the
diversity of species aggregations characteristic of mammalian carnivores. Case
and Gilpin (1974:3076) suggested that the relative costs of exploitation- versus
interference-competition favored the latter in part because "the contraction from
the fundamental niche to the realized niche is likely to be small for an interference
competitor and high for an exploitation competitor." This pattern appears evident
in the Old World tropics where dominance hierarchies among predators have been
frequently observed, but it is less apparent in the New World tropics. More diverse
landscape features, most specifically topography and vegetation, have offered very
different milieus for community evolution and likely have exerted a powerful force
on the nature of resource partitioning among sympatric carnivores. At the risk of
oversimplification, communities evolving in landscapes dominated by unforested
expanses (e.g., East Africa) tend to exhibit more interference competition than
species complexes coevolving in dense expanses of forest cover (e.g., South
America, Southeast Asia). The aggressive and dominating nature of the brown
bear in lightly forested terrain is an example of this process in North America. For
other North American carnivore communities, human-caused changes to the
landscape have affected the patterns of community organization and resource
partitioning through recent losses and additions to local carnivore faunas.
South Florida offers a variety of land cover types including expansive areas of
open, herbaceous vegetation and extensive systems of dense forest The three
remaining species of large terrestrial carnivores native to this area all confine most
activities to plant communities contained within or immediately adjacent to forest
cover (Maehr et al. 1991a; Foster 1992). The recently extirpated red wolf may
have made more use of relatively open terrain, a trait that may have facilitated its
demise. In recent years the coyote has become a more noticeable component of the
current carnivore assemblage, but little is known about its diet, distribution, and
habitat needs in South Florida.
Studies of large carnivores consistently support the notion that the
conservation of these species is a landscape-level issue. Although proposed
solutions to the problem of shrinking wildlife habitat have stimulated debate
(Harris and Gallagher 1989; Simberloff et al. 1992), all potential approaches are
land extensive. Spatial requirements of Florida panthers and black bears are
enormous. Annual home ranges of individual adult male panthers can exceed 500
km2 (Maehr et al. 1991a), and one-way dispersal movements of black bears can
exceed 140 km (Maehr et al. 1988). Telemetry studies of South Florida carnivores
span 15 years, yet government agencies are just now attempting to apply these
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
findings to management (e.g., Cox et al. 1994). Progress in landscape-level
species management is limited but includes construction of wildlife underpasses
and the purchase of the Florida Panther National Wildlife Refuge in Collier
County.
Unfortunately, the treatment of symptoms will fail to correct the root problem
facing terrestrial carnivores in Florida: large scale alteration of the landscape.
Inexorable human development of private lands in South Florida has the potential
to eliminate 45 percent of presently occupied panther range and reduce the existing
population by over 50 percent (Maehr 1990). Although the black bears of Collier
County appear to be tolerant of many anthropogenic changes to the landscape,
most people will not tolerate their presence. The result is a high rate of mortality
and injury to bears inhabiting the urban/wilderness interface. Bobcats are
commonly reported as predators of domestic livestock throughout Collier County
and can still be legally eliminated consequent to these depredations.
All three species have been studied extensively throughout their ranges
(Anderson 1983; Anderson 1987; Pelton 1982) in North America. In Florida,
published bobcat investigations, mostly in the vicinity of the Lake Wales Ridge,
span two decades. However, concern over the impact of the fur trade on bobcats
(National Wildlife Federation 1977) led to extensive fieldwork to detail population
status and trends (Florida Game and Fresh Water Fish Commission, unpubl. data).
These activities, stimulated a statewide food habits analysis that was based on
collections of stomachs obtained by trappers (Maehr and Brady 1986). In North
Florida, Conner (1982) and Progulske (1982) examined population estimation
techniques and movements, respectively. Foster (1992) described South Florida
bobcat home range characteristics in conjunction with an evaluation of highway
underpass effectiveness.
Papers detailing a variety of Florida black bear subjects span four decades.
Like bobcats, most of these studies were conducted outside of South Florida, but
they covered a greater diversity of topics. Although the greatest political issue
following the listing in 1974 of black bear as a threatened species was sport
hunting (Maehr and Wooding 1992), most studies in the state have focused on
basic natural history and bear/human conflicts. Compared to bobcats, black bears
in Florida have been the subject of more work on diseases, parasites, and non-
hunting management issues.
In view of their rarity, Florida panthers have received an inordinate amount
of scientific attention, with technical literature dating to 1950. Since then,
publications on the basic natural history of this federal- and state-listed endangered
subspecies have evolved into discussions of controversial issues ranging from
property rights to genetic restoration. More than half of the published literature on
Florida panthers appeared after 1990, so few generalizations can be made about the
panther's historical distribution. There remain few unstudied aspects of the
modern panther's biology or ecology; however, recent management has consisted
of sporadic efforts to treat symptoms associated with small population size rather
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
than addressing the basic reasons for its current status or necessary steps for
restoration.
Relative to most other species of terrestrial vertebrates in Florida, panthers,
black bears, and bobcats exist at low densities. A high degree of dispersion has
contributed to a low frequency of epizootics although individuals of all three
species are susceptible to a number of diseases, and Florida bobcat populations are
known to have suffered locally severe disease outbreaks (Wassmer et al. 1988;
Progulske 1982). Forrester (1992) examined the disease occurrence in these
species and suggested an inverse relation between body size and the likelihood of
disease. Bobcats have experienced temporary, local extinctions, while black bears
appear relatively disease-free.
Because a spatially influenced resistance to disease may improve the survival
probabilities of large, solitary carnivores, this same characteristic makes them
vulnerable to habitat fragmentation and habitat loss. Maehr (1990) argued that it
may be pragmatic to satisfy the habitat requirements of many species by meeting
the spatial needs of a single species. The biological rationale for this approach has
been debated (Wilson 1987; Terborgh 1988), but given their track records, it is
unreasonable to expect natural resource agencies, which are traditionally
underfunded and often unwilling to address multi-species management, to address
the needs of the many wildlife species that are suffering the effects of range
constriction. Thus, single-species, or trophic-level management remains as the
substitute for a landscape-level approach to biodiversity conservation.
Harris and Cropper (1992) suggested that a combination of sea level rise,
climate change, and anthropogenic influences have led to the post-Pleistocene
faunal collapse that has occurred in Florida. Assuming that current rates of sea
level rise and human population growth will continue, it is clear that Florida's
most widespread populations of panthers, black bears, and bobcats also may be the
most at risk. The displacement of tropical plant communities and the elimination
of large tracts of forest may negate landscape conservation efforts even if they are
successful in the short term.
Study Area
Field activities were conducted in extreme South Florida, primarily between
820 and 81 50' W longitude, and below 270 N latitude. The eastern portion of the
study area is bounded by the Everglades, sprawling coastal urban development, and
the Everglades Agricultural Area.
While the development of South Florida is generally equated with the
southeast coast, it is ironic that the earliest landscape-altering changes caused by
humans occurred in Southwest Florida. These changes began after passage of the
Swamp Lands Act of 1850-legislation that was intended to stimulate the
reclamation of inundated federal lands of the United States (Carter 1974). Inroads
into the interior of South Florida began with the dredging of the Caloosahatchee
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
River from the Gulf of Mexico to Lake Okeechobee. This water course, which
originally began west of the lake near LaBelle, Florida, drained the landscape on
either side of the Hendry/Glades county line but left an upland linkage between
Southwest and Southcentral Florida near Lake Okeechobee (Fig. 1.1). Although
railroads had reached Miami by 1898 (Carter 1974), the modern vision of a
drained and productive Everglades did not materialize until the campaign of
Governor Napoleon Bonaparte Broward in 1904. The first canal to connect the
Atlantic Ocean with Lake Okeechobee was dredged in 1906. This led to booming,
and sometimes fraudulent, farmland marketing that hinged upon South Florida's
rich muck soils. By 1929 over 730 km of canals aimed at draining the Everglades
were in place. Clearing for farmland resulted in the elimination of a vast forest of
custard apple (Annona glabra), a landscape feature of Lake Okeechobee's south
rim that once hid Seminole Indians from Union troops and likely facilitated the
east-west movements of many species of South Florida's vertebrate wildlife. As
human access to the lake increased, and roads and railways were built as far south
as Miami, construction began on the Tamiami Trail. Just as the dredging of east-
west canals did for ships, this highway linked the east and west coasts for
automobiles in 1928 and opened the Big Cypress Swamp to development.
With agriculture dominating much of the drainable wetlands and farmable
uplands south of the Caloosahatchee River, some land preservation in South
Florida was initiated. Everglades National Park and Collier-Seminole State Park
were established in 1947, and Corkscrew Swamp Sanctuary was dedicated in 1954.
Through the second half of this century the interplay between land preservation
and land development became a chess match whereby each advance in creating a
new preserve was countered with a new farm, pasture, or housing development.
For example, before the Fakahatchee Strand came under state ownership, all of its
merchantable timber, primarily large cypress (Taxodium distichum), was removed
by Lee Tidewater Cypress Company after the construction of an extensive network
of elevated railroad beds, and its closed canopy forest was returned to an early
successional stage (Burns 1984). Although the majority (9920 ha) of the strand
was acquired by the state of Florida in 1974, 18,522 ha bordering the new preserve
were marketed by Gulf American Land Corporation as an expansive residential
development known as Golden Gate Estates. An intricate network of roads and
canals, built to accommodate residents who may never construct homes, has now
left an indelible mark on this part of the South Florida landscape. Controversy
surrounding the construction of a regional jetport in western Dade County during
the late 1960s and early 1970s resulted in a state-sponsored land purchase that was
second in size only to Everglades National Park. The 230,770 ha Big Cypress
National Preserve was established by an Act of Congress in 1974 to conserve
natural resources and recreational opportunities. Approximately two decades
transpired before the next significant wave of additions to conservation lands
occurred in South Florida. In the meantime, the human population of Collier
County more than doubled in each of the decades starting with 1960, 1970, and
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
1980 (Fernald and Purdum 1992), and Alligator Alley (the precursor to Interstate
75) was built to serve as the second high-speed roadway to connect the southeast
and southwest coasts. The 10,120 ha Florida Panther National Wildlife Refuge
was created in 1989, and over 40,000 ha are scheduled to be added to the Big
Cypress National Preserve as the result of an unprecedented land swap between the
private sector and the federal government (Maehr 1992).
As of 1990, over 1.4 x 106 ha in South Florida were held in public ownership
(Fig. 1.1) and dedicated to conservation purposes (Maehr 1990). On the surface,
this appears to be a significant portion of South Florida under government
stewardship, and indeed, nearly 60 percent of Collier County alone is in some form
of government protection (which has led many local officials and community
leaders to proclaim that no more land-saving actions are necessary). However, the
vast majority of government land in South Florida is not conducive to agriculture
nor urban development because of harsh soil and/or hydrological conditions
(Leighty et al. 1954). In contrast to Collier County, neighboring Hendry County
withstood a conversion between 1900 and 1973 of over 50 percent of its native
cover to agricultural and urban uses (DeBellevue 1976). In the 23 years since then,
South Florida has sustained continued increases in citrus, cattle production, sugar
cane, and other agricultural land uses (Fernald and Purdum 1992) that, when
combined with the dredging of the Caloosahatchee River, the clearing of the Lake
Okeechobee custard apple forest, highway construction, and the impounding of
much of the Everglades, have effectively isolated the forests of South Florida from
the rest of the state.
The Natural Landscape
Although it lacks topographic relief, South Florida supports many recognized
vegetation communities. The high variability inherent in South Florida vegetation
communities and their descriptions (Craighead 1971; Soil Conservation Service
1981; McPherson 1984; Olmstead and Loope 1984; Myers and Ewel 1990) results
in part from the many zones of transition from one community to another, as well
as the interests of the authors. Gradations between plant communities are also
suggestive of the constant changes in species composition that have been, and
continue to be, influenced by climate. The implication of this slow but inexorable
landscape process is that vast expanses are necessary to accommodate not only the
peregrinations of wildlife populations, but also the migration of plants and entire
vegetative communities. Florida is considered more at risk from sea level rise due
to global warming than is any other state (Henry et al. 1994), and South Florida
has experienced more subsidence and consolidation of soils than any other region
of the state. Effects of recent increases in salinity were observed in Everglades
National Park by Craighead (1971), and have had negative consequences on a
variety of economically valuable environmental resources. Although sea level is
not expected to rise beyond 65 cm by the year 2100 (Henry et al. 1994), even a
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
change of this magnitude will cause widespread constrictions to the distribution of
cover types that are important to the terrestrial vertebrate carnivores of South
Florida.
Although South Florida lies within the Great Desert Belt of the earth (Henry
et al. 1994), its climate is classified as tropical savannah (Koppen 1931: cited in
Robertson 1955; Hela 1952) and monsoon rainforest (Trewartha 1943). A distinct
warm wet season is typical from May through October when 60-80 percent of the
annual average 1525 mm of rainfall occurs (Craighead 1971). The mean annual
temperature is 230C with extremes of -20C to 380C (Duever et al. 1986). Southern
Florida is often spared the effects of continental winter cold fronts due to the
influence of warm air originating from over the Gulf of Mexico and the Caribbean
(Henry et al. 1994). This has permitted the existence of a high diversity of tropical
plants including palms, epiphytic orchids, and bromeliads. Most of South Florida
is below 7.6 m above mean sea level (Wade et al. 1980). Floods, fires, freezes, and
droughts are considered to be the most important natural environmental influences
on the distribution and kinds of plants in South Florida (Robertson 1955;
Craighead 1971; Wade et al. 1980). Most non-anthropogenic fires are caused by
lightning strikes associated with summer thunderstorms.
Davis (1943) assembled the most exhaustive account of vegetation
communities in South Florida Although he used only nine broad categories, these
were further divided into 64 subclasses. This classification was used as the basis
for descriptions of bobcat, black bear, and Florida panther habitat use and home
range composition. Several of the communities that were described by Davis
(1943) were combined in order to match a current observer's ability to correctly
identify plant communities from 152 m elevation in a fixed-wing aircraft For
example, the subtle differences among 'oak and cabbage palm hammocks,'
'cabbage palm hammocks,' and 'low hammocks' were not consistently discernible
from a fixed-wing airplane; nor were they remarkably different even at ground
level. Other groupings were not used because they were unique to Southeast
Florida or they were not found in the study area. This resulted in the use of only
11 cover types for delineating the habitats of Southwest Florida terrestrial
carnivores. These are given on the following pages.
Pine flatwoods are dominated by slash pines (Pinus elliottii) growing in open
forests on moderately well-drained soils. Saw palmetto (Serenoa repens) is a
common and often dominating understory shrub.
Pine and cabbage palm woods are relatively limited in distribution and
contain slash pine and cabbage palm (Sabal palmetto) in similar abundance. Saw
palmetto is usually absent from this community.
Pine scrub is dominated by sand pine (Pinus clausa) with thickets of scrub
oaks (Quercus spp.) and other xeric shrubs.
Hardwood hammocks are found on well to poorly drained soils and are
dominated by broad-leaved deciduous oaks in association with cabbage palm and
many temperate and tropical shrubs.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Mixed swamps are inundated forests of hardwoods such as red maple (Acer
rubrum) and laurel oak (Quercus laurefolia) with cypress present but not
dominant Standing water can persist for a few months to the entire year
depending upon drainage conditions and rainfall patterns.
Cypress swamps range from the remnant stands of large specimens such as
Corkscrew Swamp to the dwarf cypress forests of the eastern Big Cypress Swamp.
Most cypress forests are characterized by long periods of inundation and low
primary productivity.
Thicket swamps are shrub forests dominated by elderberry (Sambucus
canadensis), willow (Salix caroliniana), pop ash (Fraxinus caroliniana), wax
myrtle (Myrica cerifera), or buttonbush (Cephalanthus occidentalis). These areas
are usually transition zones between swamp forests and marshlands and often
follow clearing or the abandonment of agricultural lands.
Bay tree forests are composed of broad-leaved evergreen trees including red
bay (Persea borbonia), sweet bay (Magnolia virginiana), and dahoon (Ilex cassine)
on poorly drained soils, and primarily in Highlands and Glades counties.
Freshwater marshes are treeless wetlands dominated by sawgrass (Cladium
jamaicense), flags (Thalia geniculata, Sagittaria spp., and Pontederia spp.) or
wetland grasses and sedges.
Mangroves are found in coastal estuaries in saline to brackish water and are
composed of red mangrove (Rhizophora mangle), black mangrove (Avicennia
germinans), and white mangrove (Laguncularia racemosa). These species are
usually divided into distinct zones with buttonwood (Conocarpus erectus)
inhabiting the inner-most high salinity zone.
Agricultural/disturbed areas were once occupied by vegetation as described
above but have been converted to croplands, improved pasture, rock mines, urban
areas, and roadsides.
Summary of Previous Large Carnivore Work in Florida
Until the middle of the 20th century, most published literature on or relevant
to Florida's large terrestrial carnivores dealt with general distribution, taxonomy,
or economic status (Merriam 1896; Bangs 1898; Hamilton 1941; Young and
Goldman 1946; Young 1946a). Recent studies have focused more on biological,
management, and conservation topics (Anderson 1983; Anderson 1987; Eagar and
Stafford 1974; Pelton 1982; Tumilson et al. 1982).
Bobcat
Descriptions from Florida are similar to those from other parts of the bobcat's
range: it is a secretive, solitary carnivore that specializes on small prey-especially
rabbits, rodents, and to a lesser extent, birds. Maehr and Brady (1986) analyzed
food habits throughout Florida and determined that there were no sex-related food
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
preferences, but that seasonal variation in diet involved an increased use of
artiodactyls and birds during fall and winter, respectively. The use of birds is
apparently in response to increases in over-wintering populations of migrants.
Land et al. (1993) and Wassmer et al. (1988) reported similar proportions of prey
species in bobcat diets from Southwest and Southcentral Florida; however, neither
study revealed statistically significant seasonal variation. From a range-wide
perspective, Florida bobcats utilize deer less frequently and birds more frequently
than bobcats from other regions.
Wassmer (1982) and Guenther (1980) in Southcentral Florida, and Foster
(1992) in Southwest Florida found that annual home range size varied from 11.6 to
31.1 km2 for adult males, and 5.8 to 21.6 km2 for adult females. Progulske (1982)
reported a mean of 44.4 km2 for two adult male bobcats in North Florida. Florida
bobcat home range sizes fall well within the extremes reported for the species
(Foster 1992).
Bobcats in Southcentral Florida preferred dense forest cover in an uplands-
dominated landscape matrix (Wassmer et al. 1988). Foster (1992) hypothesized
that bobcats in Southwest Florida preferred upland habitats although she did not
compare frequency of use to habitat availability. Female bobcats appear to prefer
thickets of saw palmetto for their natal dens (Wassmer 1982; Foster 1992).
Winegarner (1985b) documented a bobcat natal den in a gopher tortoise burrow
located in a dense saw palmetto thicket
Foster (1992) reported considerable overlap among adult male bobcat home
ranges in Southwest Florida, but little overlap among adult females. Wassmer et
al. (1988) recognized similar patterns in Southcentral Florida. Both studies
reported extensive overlap between males and females, and Wassmer et al. (1988)
described a pattern of home range replacement and social ecology resembling the
land tenure system described by Seidensticker et al. (1973) for mountain lions.
Reproductive characteristics of Florida bobcats have been described only as
isolated anecdotes referring to a few individuals (Winegarner and Winegarner
1982; Winegarner 1985; Foster 1992) and for a local population in Highlands
County (Wassmer et al. 1988). Based on these observations, litter size in Florida
averages between two and three.
Most reports of mortality cite natural causes. Foster (1992) found that most
of the study animals in Southwest Florida avoided paved roads and, thus, avoided
highway collisions. Wassmer et al. (1988) and Progulske (1982) found that disease
was the major cause of death in Southcentral and North Florida bobcat populations.
Although no statewide population estimates have been made, the Florida
Game and Fresh Water Fish Commission considers bobcats sufficiently abundant
to allow hunting and trapping throughout the state. Bobcats are likely still found
in every county of Florida.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Black Bear
The black bear is Florida's largest terrestrial mammal, and it exhibits patterns
of behavior and ecology that are typical of the species throughout North America.
Early studies by Harlow (1961, 1962a) summarized body measurements that
suggested black bears from Florida were as large or larger than individuals from
northern populations. Schemnitz (1974) estimated a South Florida population of
145, while Harlow (1962b) estimated that 800-1000 inhabited the entire state.
The earliest telemetry studies occurred in Northcentral Florida in response to
concerns over proposed phosphate mining in Osceola National Forest (U.S. Dept
Interior 1979). This study resulted in an evaluation of home range estimation
techniques (Mykytka and Pelton 1989) and a habitat analysis that suggested the
importance of large swamps and pine flatwoods ecosystems (Mykytka and Pelton
1990). Home ranges of two females in Osceola National Forest were 93.4 and 39.4
km2 while six males ranged from 35.9 to 457.2 km2 (Mean=171.1 km2). Wooding
and Hardisky (1988) estimated male and female black bear home ranges in Ocala
National Forest at 170 and 26 km2, respectively.
The black bear's ability to tolerate anthropogenic alterations to the landscape
is reflected in its widespread contemporary distribution (Maehr 1984; Brady and
Maehr 1985), as well as a statewide beehive-depredation problem (Maehr 1982;
Brady and Maehr 1982; Maehr and Brady 1982a). Although such interactions may
lead to bear poaching, highway collisions are the most common form of human-
related mortality (Wooding and Brady 1987). Natural mortality has been
documented infrequently but may include occasional predation by Florida panthers
(Maehr et al. 1990a) and cannibalism (Wooding and Hardisky 1988). Black bears
are susceptible to a variety of diseases and parasites (Conti et al. 1983; Pirtle et al.
1986; McLaughlin et al. 1993), but none has been demonstrated to be a significant
mortality factor (Forrester 1992).
Food habits have been examined from statewide and regional perspectives.
Maehr and Brady (1984a) measured seasonal changes that were consistent with
findings from other parts of the species' range. Food availability and diversity vary
geographically (Maehr and Brady 1982b; Maehr and Brady 1984b), however, foods
are consistently dominated by fruits, insects, and occasionally vertebrates (Maehr
and DeFazio 1985).
Like their North American conspecifics, black bears in the Ocala National
Forest exhibit seasonal movement patterns (Wooding and Hardisky 1988). While
some males remain active throughout the year, restricted movements during winter
are particularly pronounced among pregnant females.
Although black bears were listed by the State of Florida as threatened in 1974
(Maehr and Wooding 1992), fall and winter hunting were permitted in
Apalachicola National Forest and Baker and Columbia counties until 1994 when
an experimental moratorium was imposed. Despite the black bear's recently
documented occurrence in at least 50 of Florida's 67 counties (Brady and Maehr
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
1985), its distribution is almost exclusively confined to five disjunct populations.
Occasional long-distance dispersal movements (Maehr et al. 1988) have the
potential to occasionally cross the gulfs between some of these populations.
Florida Panther
The existence of the Florida panther was debated for several decades until its
"official" rediscovery in 1973 by Nowak and McBride (1973), who estimated the
South Florida population at 20-30 individuals. Although evidence of panthers has
continued to emanate from Southcentral Florida (Layne and Wassmer 1988; Maehr
et al. 1992; Maehr 1994) and the St. Johns River drainage (Maehr 1992),
concerted research efforts have been restricted to South Florida. Prior to the
capture of an old female in Glades County in 1973 (Nowak and McBride 1973),
the South Florida population was estimated to be 92 (Schemnitz 1974). Williams
(1978) placed the population at 30-50 individuals and stated that credible but
unsupported sign originated only from Collier County. Roof and Maehr (1988)
developed a standardized survey method for field verification of panther sign.
Based on such sign surveys and extrapolations from radio-collared study animals,
the contemporary population in Southwest Florida (exclusive of the Everglades and
eastern Big Cypress Swamp) is estimated at 70-80 individuals (Maehr et al.
1991a).
Young and Goldman (1946) described the Florida subspecies and its
distribution in the southeastern United States. Allen (1950) discussed
vocalizations of captive panthers, and a specimen examined by Belden and
Forrester (1980) solidified the stereotypic description of the modern subspecies-
especially the characteristic crook at the end of the tail and a whorl of dorsal hair
near the scapulae. Similarities between some panther and bobcat scats (feces) led
to an unsuccessful effort to differentiate the two species with chromatographic bile
assays (Johnson et al. 1984).
Specialized capture techniques (McCown et al. 1990) have been a part of
intensive and invasive examinations of individual panthers during anesthesia and
necropsies since the mid-1980s. As a result, a detailed catalog of parasites
(Forrester et al. 1985; Greiner et al. 1989; Maehr et al. 1995) and diseases
(Forrester 1992; Roelke et al. 1993b; Glass et al. 1994) has been assembled.
Although no parasites have been demonstrated to be pathogenic, Notoedric mange
has the potential to cause mortality at least in juveniles (Maehr et al. 1995).
Diseases that have caused mortality include bacterial infections, rabies (Roelke et
al. 1993b), and pseudorabies (Glass et al. 1994). Mortality caused by highway
collision is well documented but is less important to the wild population than
natural mortality-especially within-species aggression (Maehr et al. 1991b).
Illegal killing has not been documented for over a decade and capture-related
deaths are rare.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Panthers prefer native uplands over other habitat types in South Florida
(Belden et al. 1988; Maehr et al. 1991a; Maehr et al. 1992). Maehr and Cox
(1995) found that large patches of forest cover were important in explaining
panther occurrence and that natural and unnatural habitat fragmentation reduced
the value of these forests to panthers. Thickets of saw palmetto are important as
daytime rest sites and natal dens (Maehr et al. 1990b). Age at first reproduction in
females is 18 months (Maehr et al. 1989b) and males have not been observed to
breed before 3 years of age (Maehr et al. 1991a). Average litter size is 2.25 (Maehr
and Caddick 1995), natal sex ratios are approximately 50:50, and births have
occurred in almost every month. Survival of kittens between birth and 12 months
of age is greater than 0.80 (Maehr and Caddick 1995), and annual mortality of all
sex and age classes combined is less than 0.20 (Maehr et al. 1991b).
Florida panthers exhibit a system of land tenure typical of solitary carnivores,
and their home ranges average 519 km2 and 193 km2 for adult males and adult
females, respectively (Maehr et al. 1991a). Activity of both solitary and denning
panthers follows a bimodal pattern with crepuscular peaks (Maehr et al. 1990b).
Female panthers exhibit a regular pattern of den attendance during the two months
that kittens are unable to travel (Maehr et al. 1989a). Litter size appears to be a
function of prey abundance and habitat productivity. Attempts to artificially
augment prey availability were unsuccessful (Maehr et al. 1939c).
Concerns over nutritional status led to a preliminary conclusion that female
panthers were consistently undernourished and anemic (Roelke et al. 1985).
However, food habits analyses indicated that prey abundance and distribution
varied geographically (Maehr et al. 1990a). Panther prey in South Florida follows
a northwest to southeast gradient of declining abundance (McCown et al. 1991)
that appears to be a product of soil quality and primary productivity. Wild hogs
(Sus scrofa) are the most frequently taken prey; however, this species is sparse
south of Interstate 75. White-tailed deer (Odocoileus virginianus) and wild hogs
combined account for 70 percent of the frequency of occurrence in panther scats.
Where both species are abundant (i.e., the north part of the range), panthers are
larger, more abundant, and produce more kittens. This led Maehr (1990) to
emphasize the importance of private lands in Collier and Hendry counties to the
future of the subspecies.
At least some rationales argue that low numbers increase the extinction
probabilities for small populations. In addition to demographic stochasticity and
unpredictable climatic events, genetic problems have been suggested as a primary
threat to panthers (Roelke et al. 1993a). O'Brien et al. (1990) identified two
distinct lineages of wild panthers in South Florida-one originating in situ, the
other originating from captivity. Despite this apparent introgression, they
concluded that the South Florida population was suffering from reduced allozyme
variation when compared to other cougar populations. Spermatozoa abnormalities
(Barrone et al. 1994), heart defects, infectious diseases, and matings between close
relatives (Roelke et al. 1993a) have been suggested as symptoms of a collapsing
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
population. However, Maehr and Caddick (1995) reminded that philopatry is
expected in a land tenure social system, and thus, matings between close relatives,
especially males and their female offspring, are typical. O'Brien et al. (1990) led
Harris (1990) to point out that the reason for the genetic variation documented in
South Florida may date to the Pleistocene connection between Florida and the
Yucatan Peninsula. Regardless of the panther's lineage in South Florida, normal
demographics, as indicated by behavior typical of the species-low mortality, high
natality, and kitten survival, may be indicative of a high level of local adaptation.
These factors may be ameliorating the effects of small population size and reducing
the potential for genetic problems to be immediate conservation concerns (Maehr
and Caddick 1995).
General Methodology
The data upon which this study is based were collected primarily while I was
the supervisor of research for the Florida Game and Fresh Water Fish Commission
in South Florida from 1985 to 1994. Field activities focused primarily on Florida
panther captures and the monitoring of their radio-collar signals. This work began
in 1981 and continues to this day. Methods of panther capture and restraint have
been described in detail by McCown et al. (1990) and Barrone et al. (1994).
Bobcats were captured opportunistically primarily during 1986 and 1987 while
panther hunting with hounds trained to trail and tree cats. Bobcats were handled
in a fashion similar to panthers, but due to their smaller size, they were fitted with
smaller radio collars with functional lives of no more than one year. Black bears
were captured with Aldrich spring-activated snares and with culvert traps
(Erickson 1957) primarily during the three-year span 1991-1993. Bears were
anesthetized with a pole syringe using Ketamine hydrochloride at a dosage of 20
mg/kg. Radio collars worn by adult black bears and adult panthers had battery
lives of at least two years. Florida panthers were captured as necessary to replace
aging transmitter batteries and maintain contact with study animals.
All study animals were regularly monitored from fixed-wing aircraft at an
altitude of about 150 m following the methodology of Mech (1983). Florida
panthers were located three times per week, black bears were located three times
every two weeks, and bobcats were located approximately once each week.
Location data included Universal Transverse Mercator coordinates, habitat type,
time of day, animal identification number, and an index to activity if the study
animal carried a transmitter that contained a motion-sensitive switch (Telonics,
Inc., Mesa AZ). Additional telemetry data used in these analyses for panthers
monitored by the National Park Service or following the termination of my
involvement with field activities were obtained through requests to the Florida
Game and Fresh Water Fish Commission's Office of Environmental Services.
More specific field methods and the statistical analyses used are described in detail
within subsequent chapters.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Table 1.1. The terrestrial mammalian carnivore of North America north of Mexico presumed to be present
at the time of European colonization. Mass estimates represent species means (female and male) and were
derived from Walker (1975), Burt (1975 and Chanman and Feldhammer (1982).
Species Mass Status in Florida
Black bear (Ursus americanus)
Brown bear (Ursus arctos)
Polar bear (Thalarctos maritimus)
Gray wolf (Canis lupus)
Red wolf(Canis rufis)
Coyote (Canis latrans)
Red fox (Vulpes vulpes)
Swift fox (Vulpes velox)
Kit fox (Vulpes macrolis)
Gray fox (Urocyon cinereoargenteus)
Arctic fox (Alopex lagopus)
URSIDAE
150kg
250 kg
300kg
CANIDAE
42kg
25kg
15kg
5kg
3kg
2kg
4kg
5kg
PROCYONIDAE
Cacomistle (Bassariscus astutus) 1 kg
Raccoon (Procyon lotor) 10 kg
Coatimundi (Nasua nasua) 9 kg
MUSTELIDAE
Ermine (Mustela erminea) 100 g
Least weasel (Mustela nivalis) 50 g
Long-tailed weasel (Mustela frenata) 200 g
American mink (Mustela vison) 1.1 kg
Black-footed ferret (Mustela nigripes) 1 kg
American pine marten (Martes americana) 750 g
Fisher (Martes pennant) 3.5 kg
Wolverine (Gulo gulo) 20 kg
American badger (Taxidea taxus) 8 kg
Spotted skunk (Spilogale putorius) 700 g
Western spotted skunk (Spilogale gracilis) 700 g
Striped skunk (Mephitis mephitis) 2.5 kg
Hooded skunk (Mephitis macroura) 2 kg
Hog-nosed skunk (Conepatus mesoleucus) 3 kg
Hog-nosed skunk (Conepatus leuconotus) 3 kg
River otter (Lutra canadensis) 8 kg
FELIDAE
Lynx (Lynx canadensis) 10 kg
Bobcat (Lynx rfuis) 10 kg
Ocelot (Felis pardalis) 13 kg
Margay (Felis weidii) 2.5 kg
Jaguarundi (Felisyagouaroundi) 7.5 kg
Puma (Felis concolor) 60kg
Jauar (Panthera onca) 80 kg
threatened
not native
not native
not native
extirpated
naturalized/introduced
naturalized
not native
not native
resident
not native
not native
resident
not native
not native
not native
resident
resident
not resident
not resident
not resident
not resident
not resident
resident
resident
resident
not resident
not resident
not resident
resident
not native
resident
not resident
not resident
not resident
resident
not resident
.......~~.......~........... ...~....................................
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
A Florida Panther National Wildlife Refuge
B Southern Golden Gate Estates
C Fakahatchee Strand State Preserve
D Big Cypress National Preserve
E Big Cypress Addition Lands
F Big Cypress Seminole Indian Reservation
G Rotenberger/Holy Land Wildlife Areas
H Water Conservation Areas
I Everglades National Park
Figure 1.1. Study area and large tracts of publicly owned land in South Florida.
^
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
2. DIETARY OVERLAP
Although the actual nutritional requirements of most wildlife species are
unknown, food remains the most commonly examined resource for assessing the
degree of interspecific competition (Hutchinson 1957; Caughley and Sinclair
1994). The food habits of native large terrestrial carnivores in Florida have been
well described (Maehr and Brady 1982, 1984a; 1984b; Maehr and DeFazio 1985;
Maehr and Brady 1986; Maehr et al. 1990; Wassmer et al. 1988). However, they
have not been examined for potential dietary overlap. Further, published food
habits data are primarily from North Florida for black bears, Southcentral Florida
for bobcats, and from South Florida for panthers. Black bears in North Florida
exhibit only modest differences in food habits (Maehr and Brady 1984b), and
bobcat diets in South Florida are similar to those reported for the entire state (Land
et al. 1993). I examined previously published data for bobcats and Florida panther
food habits, and compared these with unpublished food data for black bears in
South Florida.
Methods
Collection, identification, and analytical procedures for foods of bobcats and
panthers can be found in Maehr and Brady (1986) and Maehr et al. (1990).
Because volumetric measurements were made for contents of bobcat stomachs,
these data were converted to percent frequency in order to allow for direct
comparisons with other species. Black bear scats were collected throughout South
Florida at trap sites and during routine field activities associated with radio
telemetry studies. Scats were rinsed with water through a 1 mm sieve and
individual food items were separated in a white enamel wash pan. Reference
collections and guides (Martin and Barkley 1961; Schopmeyer 1974; Tomlinson
1980; Arnett 1985) were used to identify foods as close to species as possible.
Black bear foods were then examined by month in order to detect seasonal patterns
related to food availability or preference. These patterns formed the basis for
seasonal comparisons among the three native large carnivores in South Florida.
Although the possibility for gender-related differences in diet exists, Maehr
and Brady (1986) found that male and female bobcats had similar food habits,
Anderson (1983) did not report sex-related differences in cougar diets, and
Schwartz and Franzmann (1991) found that black bears exhibited no sex-related
differences in rate of moose calf (Alces alces) predation. Therefore, gender was
ignored in comparisons of diets. Sorensen's similarity coefficient (Sorensen 1948;
Greig-Smith 1964) was used to quantify the amount of annual dietary similarity
between bears, bobcats, and panthers using species occurrence data from Maehr et
al. (1990), Land et al. (1993), and this study. Dietary overlap between species was
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
estimated by using Pianka's (1986) variation of an algorithm first presented by
MacArthur and Levins (1967):
Ok= ZPuPa
j j
where Pi is the proportion of food resource in the ith species class, and n is the total
number of species categories. Ojk then, has a possible range of values from 0 to 1.
Higher values equate to higher levels of overlap. Shannon-Weiner indices of
diversity (Shannon and Weaver 1963) were calculated using percent frequency of
foods. Because not all cited studies identified small mammals, birds, and
lagomorphs to species, these items were grouped into three categories.
Nutritional analyses were conducted on selected black bear foods that were
frequently consumed in South Florida. Food items were collected in occupied
black bear range in South Florida, oven-dried at 6000C, and ground in a Wiley
mill. Analyses conducted at the Forage Evaluation Support Laboratory, Animal
Nutrition Lab, University of Florida, Gainesville, measured dry matter, organic
matter, total neutral-detergent fiber, ash-free neutral-detergent fiber, total nitrogen,
crude protein, in vitro organic matter digestibility, and total phosphorous. Crude
fat was measured by A & L Plains Agricultural Laboratories, Inc., Lubbock, Texas,
using ether extract methodology. Ants were washed, separated, and dried at 1000C
for 48 hours, and milled through a 1 mm screen at the Caesar Kleberg Wildlife
Research Institute, Texas A & M University, Kingsville, Texas. Milled samples
were dried again and 2-g aliquots of ground ants were extracted for eight hours
with petroleum ether. Samples were dried again, weighed, ashed at 6000C for five
hours, dried and weighed.
Results and Discussion
The three native carnivores in South Florida exhibited distinct trends in their
utilization of important species or groups of species. Results of food habits studies
from South Florida were comparable to the results of food habits studies of the
same species in more northern Florida locales (Table 2.1).
Bobcat
Maehr and Brady (1986) found that Florida bobcats specialized on small prey
and killed white-tailed deer infrequently. Land et al. (1993) confirmed this general
pattern for Southwest Florida, although in their study of female deer mortality
within the range of the Florida panther, bobcats killed more deer than did panthers.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Maehr and Brady (1986) attributed bobcat consumption of deer to crippling and
mortality caused by sport hunting, whereas Land et al. (1993) believed that
predation on deer was caused by a small proportion of the local population that
occasionally ambushed prey in habitats that panthers generally avoided (i.e.,
freshwater marsh). Seasonal variation in Florida bobcat diets may be due to an
influx of overwintering migrant birds, hunter harvest of large prey, and annual
patterns in small prey reproduction (Maehr and Brady 1986). Much of South
Florida is closed to doe hunting, and mild winters maintain food supplies for small
mammals. Thus, hunter crippling/mortality, and annual fluctuations in small
mammal abundance are likely of lesser influence on bobcat nutrition than the
sometimes five-fold increases in overwintering bird densities that occur each year
(Robertson and Kushlan 1974).
Florida Panther
Maehr et al. (1990) found that Florida panthers specialized on large prey,
especially wild hog and white-tailed deer. Proportions of food items in the diet did
not change seasonally; however, smaller prey such as raccoons were consumed in
areas with low densities of large prey. These areas also support lower panther
densities with only sporadic reproduction (see Maehr et al. 1989). In Everglades
National Park, where panthers became effectively extinct in 1991 (Bass and Maehr
1991), panthers occasionally consumed river otters (Lutra canadensis), bobcats,
and alligators (Alligator mississippiensis) (Dalrymple and Bass 1996), apparently
because deer occurred at low densities (Smith and Bass 1994). Like populations of
cougar throughout North America, the Florida panther seems inextricably tied to a
resident deer population.
Black Bear
Despite copious food habits data on Florida black bears, none of the studies
was conducted in South Florida where tropical climate and seed sources have
created a much different milieu than the habitats available to bears in Central and
North Florida. Analysis of 739 scats collected from July 1991 through 1993
indicated that black bears in South Florida consumed at least 40 species or distinct
parts of plants, insects, and mammals. Several species including saw palmetto,
cabbage palm, giant palm weevils (Rynchophorus cruentatus), and social insects
provided at least two plant parts or life stages as food. Apical meristems and seeds
were available on both of the palm species, whereas eggs, larvae, adults, and honey
(when available) of colonial insects were eaten. Several species did not appear in
scats but were observed to be eaten, such as Florida damp-wood termites
(Prorhinotermes simplex), or have been reported previously, for example, alligator
eggs (Maehr and Brady 1984a).
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
Monthly analyses of food habits (Table 2.2) were used to separate the year
into categories that corresponded to plant phenology and bear behavior related to
denning (Fig. 2.1). This resulted in the subjective division of the year into three
seasons: winter (January-April), summer (May-August), and fall (September-
December). Winter foods were characterized by a preponderance of soft mast,
primarily the fruits of Brazilian pepper (Schinus terebinthefolius), and plant fibers
such as alligator flag (Thalia geniculata), and pickerel weed (Pontederia cordata)
(Table 2.3). Summer foods were dominated by plant fibers and insects, and
included the fruit of swamp dogwood (Cornus foemina) and lantana (Lantana
spp.). Swamp dogwood fruits are locally abundant and very high in crude fat
relative to other plant foods (Table 2.4). Such high-energy foods are unusual for
this time of year in other parts of the black bear's range. Although summer and
winter diets appear similar when only major categories are compared (Table 2.3),
these two seasons are distinguished primarily because of the widespread
availability of Brazilian pepper seeds in winter when few other seeds are available,
and because ant consumption increases during May. In addition, lantana, which is
a tropical genus that contains at least one native species as well as several
naturalized forms (Nellis 1994:136), is available primarily during early summer.
Fall foods were mostly seeds of saw palmetto, cabbage palm, and to a lesser degree,
live oak (Quercus virginiana). This seasonal pattern in food habits is similar to
other descriptions of black bear food habits in the southeastern U.S. (Hardy 1974;
Landers et al. 1979; Beeman and Pelton 1980; Eagle and Pelton 1983; Maehr and
Brady 1984a; Smith 1985b; Garner 1986; Hellgren and Vaughan 1988), where an
abundance of hard mast, such as acorns, follows a period of soft fruit availability
and precedes winter denning and hibernation. This period has been described as
critical to determining reproductive output the following winter, and mast failures
have caused measurable impacts to cub production the following year (Rogers
1976). South Florida, however, has a strong tropical influence and has been
invaded by a very abundant winter-fruiting exotic shrub (Brazilian pepper).
Further, native plants, such as saw palmetto and cabbage palm, provide food year-
round, a sharp contrast to nutritional opportunities for black bears in those parts of
North America devoid of native palms and without introduced, food-producing,
tropical shrubs.
This study recorded several food items that were previously unreported for
black bears. These included stems of sawgrass, leaves and flowers of bromeliads
(Tillandsia spp.), flowers of thistle (Cirsium horridulum), seeds of marlberry
(Ardisia escallonioides), seeds of royal palm (Roystonea elata), giant palm
weevils, and colonial semi-arboreal ants (Crematogaster pilosa). The first two of
these new species may be important foods during times of limited soft and hard
mast availability. The latter two are of interest because they are highly nutritious
and involve adaptive feeding strategies.
Giant palm weevils feed and reproduce in damaged palms (Woodruff 1967),
and I have frequently observed weevils colonizing recently damaged cabbage palms
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
and palmettos throughout Collier County. The damage was caused by the
deliberate extraction of the apical meristems for human consumption-an activity
that mimics the damage caused by black bear feeding. Given that other palm-
damaging forces are rare in South Florida (i.e., lightning and wind do not appear
to damage either species), the creation of feeding and egg-laying conditions for
giant palm weevils may depend largely on the activities of humans and black bears.
If these weevils benefit from the creation of feeding and egg-laying conditions, and
black bears occasionally return to previously damaged plants and consume the
weevils, this may represent a symbiotic relation that hinges on South Florida's
native palms. In other words, black bears are known to utilize "hearts-of-palm" as
foodstuff. The damaged palms apparently release a volatile pheromone-like
compound that attracts palm weevils. Black bears that return to a palm or palmetto
that they had previously fed upon are further rewarded by the presence of nutritious
palm weevils.
The small, semi-arboreal ant, Crematogaster pilosa, builds wasp-like nests in
shrubs and stout herbaceous vegetation in wet prairies and thicket swamps. While
tracking radio-collared bears from aircraft, trails were visible in marshes
surrounding the Fakahatchee Strand, and individual bears were occasionally seen
standing in open settings along these trails. Subsequent field investigations
revealed the trails were made by black bears venturing out of the dense mixed
swamp forest to feed on these tiny (3-5 mm long), but abundant insects. Ether
extract analyses indicated that the crude fat content of adult Crematogaster exceeds
the fat content of white-tailed deer flesh (Table 2.4) and was nearly four times
greater than the fat content of the commonly consumed Florida carpenter ant
(Campanotusfloridanus).
The availability of alternative high-energy foods may help explain the low
frequency of mammalian prey in the diets of South Florida black bears compared to
bears from other parts of the species' range. For example, Schwartz and
Franzmann (1991) found that early summer diets of black bears in Alaska would
provide insufficient nutrition without the frequent consumption of moose.
Although Rogers (1987b) concluded that black bears specialize on plant foods
because they are poor predators, their carnivore dentition still offers this alternative
when animal prey are available. Although domestic livestock, wild hogs, and
armadillos are common, noisy, and often unwary potential prey in South Florida,
they were rarely consumed by bears. Thus, the year-round availability of a variety
of plant and insect foods (Table 2.3) may not only reduce potential conflict with
livestock owners and apiarists but may also reduce the likelihood for competition
with bobcats and panthers.
Nutritional analyses of frequently consumed foods indicated that a high
energy and moderate-protein diet can be maintained by black bears throughout the
year without the consumption of vertebrates which are high in both crude fat and
crude protein (Robbins 1983). In Florida, 70 percent of panther and 51 percent of
bobcat diets are composed of two species of mammals (Maehr and Brady 1986;
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
Maehr et al. 1990). The ability of these cats to subsist on the much lower diversity
diet is certainly a reflection of the constant availability of prey, which, in turn,
reduces seasonal variation in home range use.
Most black bears in this study and elsewhere (Pelton 1982) exhibit extensive
fall movements. Such movements appear to be a universal, if not annual,
phenomenon that precedes denning, hibernation, and successful overwintering in
temperate North America. In South Florida however, most bears remain active
through the winter and feed on a variety of fibrous plant material as well as
Brazilian pepper, which is not only widely distributed throughout South Florida
but is also one of the highest energy plant foods anywhere in the black bear's
range. South Florida black bears ate the apical meristems of palms and the
vegetative parts of several emergent plants in every season. Although these species
are low in fat and protein, they are highly digestible (in vitro organic matter
digestibility=93.8 percent for cabbage palm heart, and 83.6 percent for Thalia),
and there was always at least one abundant fruit high in available energy. This
year-round availability of plant and insect foods, many of which are high in lipid
content, may also help explain the rapid mass growth and early age of first
reproduction that has been documented for South Florida black bears (Maehr et al.
in press).
Compared to black bears from North Florida, the fall diet in South Florida
bears contains a considerably greater variety (Table 2.5). Maehr and Brady
(1984b) suggested that saw palmetto fruit may not be preferred, because bears in
Northwest Florida consumed black gum (Nyssa biflora) and odorless bayberry
(Myrica inodora) with greater frequency when all three species were available.
This may be true for a short period of time in North Florida inasmuch as Treichler
et al.(1946), Bonner (1971), Short et al.(1975), and Hellgren and Vaughan (1988)
found that the fruit of the closely related Nyssa sylvatica is higher in crude fat than
is saw palmetto. However, North Florida food habits studies were conducted where
black bears may have avoided upland habitats when hunter activity along roads
was highest during the legal fall bear season. Further, the extensive home range
shifts of radio-collared bears to areas of abundant saw palmetto, and the dominance
of its fruit in bear diets in this study suggest that saw palmetto fruit is in fact
preferred in South Florida.
It has been suggested that black bears in South Florida avoid such potential
foods as gallberry (Ilex glabra), American beauty berry (Callicarpa americana),
and Florida trema (Trema micrantha) because these species are extremely
common, regularly produce fruit, and are widely distributed yet contribute little or
nothing to the bear's diet. Although nutritional analyses were not conducted for
these three species, Landers et al. (1979) found that gallberry was low in both
protein and fat content. A similar phenomenon was found among North Florida
bears where gallbery is very abundant, produces fruit regularly, but is consumed
relatively infrequently compared to species of higher nutritional quality (Maehr
and Brady 1984a).
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Species Comparisons
Given their similar lifestyles, bobcats and panthers had more prey in common
with each other (0.57) than did either species with bears (Table 2.6). In addition,
the diets of both cat species were comparably diverse (Table 2.5). Black bears
overlapped less than 0.20 with either bobcats or panthers, and this overlap was
almost totally due to the occasional consumption of armadillo, white-tailed deer,
and wild hog flesh.
While the Sorensen similarity coefficient is useful as an index to prey species
overlap among predators, it does not take into account the differential use of these
foods. The Pianka algorithm also has its shortcomings, but it utilizes frequency of
occurrence data and thus, from a potential competition perspective, is likely better
for portraying the actual degree of resource-use overlap between species. These
calculations suggest that even between cat species there is little food overlap (Table
2.6, Fig. 2.2). The predatory lifestyle of black bears in South Florida appears to be
purely opportunistic and is clearly demonstrated by Pianka overlap coefficients of
less than 0.02 with both cat species. Similarly, the apparent overlap between
panthers and bobcats was diminished when frequency of occurrence was
considered. While considerable mortality is inflicted on some populations of large
ungulates in other regions by black bears (Behrend and Sage 1974; Franzmann et
al. 1980; Ozoga and Verme 1982; Verspoor 1983; Wilton 1983; Franzmann and
Schwartz 1986; Matthews and Porter 1988) and bobcats (Hamilton and Hunter
1939; Pollack 1951; Westfall 1956; Beale and Smith 1973; Turkowski 1980;
Toweill and Anthony 1988), conditions in South Florida do not compel these
carnivores to consistently prey upon large vertebrates. Prevailing climatic
conditions prolong growing seasons for temperate plant species, allow the
establishment of both naturally and artificially established tropical plants, and
encourage stability in prey populations. These factors may help explain the
infrequent predation by South Florida black bears on large vertebrate prey,
infrequent killing of livestock by panthers, and the predominance in South Florida
bobcat diets of small-sized prey throughout the year. Moreover, influxes of
wintering migrant birds boost prey opportunities without requiring bobcats to shift
their home ranges in order to maintain nutrition during temporary periods of small
mammal scarcity.
The black bear, Florida panther, and bobcat trace their ancestries to well
before the Pleistocene (Webb 1974) at a time when very different environmental
conditions prevailed. Stirling and Derocher (1989) suggested that the black bear
has remained virtually unchanged for lxl06 years, and all three species have
adapted to changes in food availability that can be measured over geological time.
Florida's three native carnivores are similar because they are all adaptable species
that can fill distributional extremes. It is of interest that interference competition
has been documented in the relatively open Everglades (where panthers killed and
consumed bobcats, Dalrymple and Bass 1996), and bobcats were the major source
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
of mortality on a deer population that inhabited an open, freshwater marsh in Big
Cypress National Preserve (Land et al.1993). In the latter case, panthers were also
permanent residents but avoided the open marshes where bobcats preyed on deer.
Hence, utilization of a similar food source was facilitated by habitat separation in
the Big Cypress Swamp, but in the relatively treeless Everglades, panthers exerted
interference competition over the bobcat. Despite the panther's competitive
dominance, bobcats are now the only native cat species permanently inhabiting
southeastern Florida. It is possible that the existing carnivore community in
southeastern Florida, where the largest two species are now rare, is an artifact of
human-induced landscape changes in the region. The elimination of the Atlantic
Coastal Ridge forest that once bordered the herbaceous expanse known as the
Everglades, may be the most significant factor in the decline of black bears and
Florida panthers in southeastern Florida, and may explain the local abundance of
bobcats. In general, however, available food appears to be effectively partitioned
among the region's three largest carnivores where forests dominate the landscape.
Table 2.1. Comparison of food habits among South Florida's native large mammalian carivores. Data
summarized from Maehr and Brady 1986', Land et al. 19932, Maehr t al. 1990a&, Maebr and DeFazio
1985', and this study_'.
SPECIES
Percent frequency in diet
Food type Bobcat' Bobcat2 Panther' Black Black
Bear4 bear'
Rodents & insectivores 36 36 2 0 0
Lagomorphs 25 37 4 0 <1
Birds 16 14 <1 1 0
Opossum 1 0 0 0 0
Armadillo 0 0 8 1 <1
Raccoon <1 7 12 0 0
W.t deer 2 3 28 <1 <1
Black bear 0 0 <1 0 <1
Feral hog 1 0 42 <1 <1
Livestock 0 0 2 0 <1
Alligator 0 0 <1 <1 0
Other herps <1 1 <1 <1 0
Insects 0 0 0 30 16
Plant fiber 11 6 27
Softmast 0 0 0 22 23
Hard mast 0 0 0 25 30
Table 2.2. Frequency of occurrence by month of foods eaten by black bears in south Florida 1991-1993. Numbers below months
Srepreent scats per month.
J F M A M J J A S O N D
.... ........................................................... ......... .I ........... A .......... M .......... 7 .......... v .......... Aq .......... N .......... 7;3.......... ..i .......... j ........... .I .....
Plant fibers
Serenoa reopens
Sabal palmetto
Pontederia cordata
Cladium iamaicense
Thalia geniculata
Potamogeton spp.
Cirsium horridulum
Tilandsia spp.
Graminae
Unknown
Soft mat
Psychotria nervosa
Psychotria sulzneri
Lantana involucrata
Vitis spp.
Persea borbonia
Celtis laevigata
Callicara americana
Ardisia escalloniodes
Schinus terebinthefolius
Ilex cassine
Comus foemina
Smilax spp.
Rubus spp.
Unknown
Hard mast
Serenoa reopens
Sabal palmetto
uercus spp.
1 1 9 4 19 6
5 9 6 1 15 1 4 4
11 2 2 3 14 1 11 2 2 6
2 1 36 7 2 1 1
16 2 1 1 1 7 5 3 14
1
23
2 1 3
2
1 9 16
67 8 2 1 1
4 2
1
10 20
3
2
4
17 12 19
7 1
1
14 1
1
8 3 9 45 89
3 36
4 3
15 5
11 16
2
16 33
2
4 2
5 2 7
5 6 7
4 1
2 31 65
5 2
3 1
1
36 13
77 74
1 4 16 31 D
Table 2.2.
SPECIES
Insects
Care pallida
Roystonea elata
Odontotaenius disiunctus
Rynchophorus cruentatus
Polistes spp.
Apis mellifera
Xvlocooa spp.
Campanotus floridanus
Vespula squamosa
Unknown Coleoptera
Cicadidae
Unknown wasp
Crematogaster pilosa
Unknown insect
Vertebrates
Dasypus novemcinctus
Odocoileus virginianus
Sus scrofa
Ursus americanus
Svlilausa spp.
Caa spp.
Bone
Eggshell
Human origin
1
1 1
5 21
5
2 2 1 2 6
4 4 3 10
1 1
3
5 9
1
2 4 1
3 2
2 12 33 3
3 9 20 5
2 8 1
3 4
1 1
3 8
1
2 3 1
2
1 1
1
1 6 2
1 2
kmnimt
-------' '-------' '-----------
--------------
--- ----
J F M A M
J Jn A S 0 N
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Table 2.3. Seasonal chaes in percent quency of food types in South Florida black bear diet
Percent freency
Season Plant fiber Soft mast Hard mast Insects Vertebrate Artificial
Winter 42.6 25.9 7.4 1".5 5.5 0
Summer 47.6 22.5 3.4 22.5 1.4 2.5
Fall 19.4 20.1 42.6 15.5 2.1 0.3
Table 2.4. Nutrient composition of foods that accunt for 70.2 nrcent ofthe diet of black bear. loi mouth 1Plgwuda
% Ash- %
% Crude Dry % Total fee % Total Total %
...Fd Im ... .. ....i .t_ ......... rten S matter NDPF' NDF N2 P3 Crude fat
Cabbage palm Fruit 13.3 6.27 90.2 66.3 65.8 1.00 2.99
Saw palmetto Fruit 12.7 4.92 89.0 48.3 46.4 0.78 0.119 9.42
Brazilian pepper Fruit 11.5 730 93.0 36.2 35.6 1.16 0.219 10.28
Alligator flag Fiber 6.4 18.02 88.9 40.3 393 2.88 0.85
Carpenter ant Adult 5.0 11.68
Saw palmetto Fiber 4.5 17.83 87.0 45.7 44.5 2.85 0.46
Cabbage palm Fiber 4.5 19.69 87.6 28.9 27.6 3.15 1.99
Swamp dogwood Fruit 3.4 6.13 95.2 54.6 52.3 0.97 0.168 17.16
Oak4 Fruit 3.4 5.90 18.7 23.8 4.30
Wild grape Fruit 2.2 7.75 91.6 36.2 36.6 1.24 0.202 4.50
Thistle Bloom 1.5 9.20 94.4 47.1 46.9 1.46 0.333 4.03
Deer' Flesh 0.6 47.4 0 0 41.30
Arboreal ant Adult 1.2 - 45.45
OallFruit 0 4.90 12.8 3.40
'neutn1demigent fibe
itrbogan
'phoupho f
4Shrt nd Epps 1976
'Lnde at al 1979
"CuerogaudUrpdaoa
'McCunogh andUley 1983
Table 2.5. Shannon and Weaver (1963) indices of diversity for large native terrestrial carnivore diets in Florida. Higher values indicate
greater dietary variation.
Fall
species .......Location Reference Annual H' H'
Florida panther Southwest Florida Mabr et al. 1990 1.51
Bobcat South central Florida Wasmer metal. 1988 1.88
Bobcat Southwest Florida Landet al. 1993 1.39
Bobcat North Florida Maehr and Brady 1986 1.51
Black bear South Florida This study 3.00 2.60
Black bear Northeast Florida Maehr and Brady 1982 1.49
Black bear Northwest Florida Maehr and Brady 1984b 1.69
Table 2.6. Dietary overlap among native large terrestrial carnivores in south Florida. Values approaching 1.0 indicate highly similar diets
between species.
Sorensen's similarity coefficient comparisons (based on species occurrence in diet)
Species. .. .... Bobcat Florida panther Black bear
Bobcat 1
Florida panther 0.57 1
Black bear 0.17 0.19 1
Pianka's resource overlap algorithm mparions (based on pernt occurrence in diet)
Species Bobcat Florida panther Black bear
Bobcat 1
Florida panther 0.13 1
Black bear 0.002 0.015 1
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
Z
0i1
z
ee
'L
I-
Z40
il20
0
Jan Feb Mr Apr May Jun Jul Aug Sep Oct Nov Dec
MONTH
E] Huma orignh Ve tabr L I mel
E so Waml 0 Hanrd mt Pblan ber
Figure 2.1. Temporal variation in black bear food consumption in Southwest Florida from 1991-1993.
0
so
.630
a
e20
L-
10
Black Bear Florida Panther Bobca
--A-- .....0..... -
*
I /
f
0 I
0/"..... ,
/ ...
,.. / ...... ...
i .
a
SFood Categorie
Figure 2.2. Food habits overlap among black bears, bobcats, and Florida panthers in Southwest Florida.
- -------------- -----------~
I
L
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
3. HABITAT USE AMONG SOUTH FLORIDA'S
LARGE MAMMALIAN CARNIVORES
A diverse array of large mammalian herbivores in East Africa uses the same
space by partitioning food resources (Lamprey 1963; Jarman and Sinclair 1979).
In the same landscape, five large mammalian predators utilize a common herbivore
biomass by a variety of social strategies, preying on different species, or even
partitioning the same species (Bertram 1979). These are but two examples of
resource partitioning among similar species and illustrate coexistence among
organisms with similar life styles (see Caughley and Sinclair 1994:145). They
provide evidence that the prospect of competition can result in intricate resource
partitioning mechanisms.
Most of the aforementioned studies occurred in settings where food habits and
habitat preferences could be determined by direct observation. In South Florida,
terrestrial carnivore behavior is hidden beneath a canopy of dense forest and/or
darkness; thus interpretations of habitat use are complicated by secretive species.
Aerial radio-telemetry eliminates the problem of error implicit in ground
triangulation, but flights restricted to daylight hours may uncover only a portion of
these species' spatial activities (Mech 1983), and most behavior must be inferred
from interpretation of spoor and telemetry data. Thus, inferences made about
habitat use must be viewed with caution, especially if the study species are
nocturnal or crepuscular.
Maehr et al. (1991a) found that nine Florida panthers monitored from 1985 to
1989 preferred upland forests to open and/or denatured habitats. However, this
analysis ignored the potential impacts of annual variation and social status of the
study animals. Habitat use analyses in Maehr et al. (1991a) included two non-
reproductive adult females (#08, #18), two non-resident adult males (#13, #20),
and an adult female that was captured as a kitten (#19). Foster (1992) examined
home range use patterns in South Florida bobcats but did not consider seasonal
effects, nor habitat use relative to its availability. Wassmer et al. (1988) examined
bobcat ecology in Southcentral Florida and found that among natural habitats
closed-canopy forests were preferred over more open forests. Habitat preferences
in South Florida black bears have not previously been examined.
Machr and Cox (1995) utilized over 10 years of telemetry data to illustrate the
importance of forest cover in explaining panther distribution and abundance
throughout South Florida. At such a large scale, inherent biases in landscape data,
such as inaccurate cover type identification, are likely insignificant. But even at
the scale of individual study animals, observations of field sign, and the trailing
behavior of hounds have not revealed patterns of habitat use that differ from
previous analyses of telemetry data (Maehr et al. 1990, 1991a). Although I have
seen tracks of panthers in unforested settings, their discovery in such open areas is
unusual, and the appearance of these tracks usually indicates directional travel to
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
the nearest forest patch. Black bears were found to be active primarily during
daylight in South Florida (see home range and land tenure chapter). The discovery
of bobcat sign is most often associated with trails through wooded terrain (pers.
observe) suggesting that bobcats do not typically venture far from forest cover.
Therefore, even though this study did not depend upon data collected at night,
there appears to be reasonable evidence to suggest that daytime radio locations are
a reasonable representation of habitat use patterns among panther, black bear, and
bobcat in South Florida. This chapter focuses on patterns of habitat use exhibited
by South Florida's large mammalian carnivores as revealed by radio-telemetry.
Methods
Habitat use was determined by identifying the vegetative cover types
associated with each radio-location. While radio-locations were fixed points
defined as Universal Transverse Mercator (UTM) coordinates, error associated
with observer variance and map accuracy precluded the determination of habitat
type solely from this cartographic system. Using the aerial tracking methodology
described by Mech (1983), vegetative cover types were recorded as independent
variables that were associated with a pair of UTM coordinates. Thus, even though
some coordinate pairs may have imprecisely pinpointed a two-dimensional
location, the habitat type was not affected by as many potential sources of error.
Annual variation in habitat use was examined by comparing years for those
individuals that were monitored for longer than one year. Several Florida panthers
were monitored for more than three years, whereas most black bears were
monitored for fewer than three years. Bobcat transmitters rarely functioned for
more than one year, so this species was not included in this analysis. Chi-square
analysis (p=0.05) was used to compare habitat percent frequencies between
consecutive years for selected individuals that were monitored for more than one
year.
Multiple analysis of variance (PROC MANOVA, SAS Institute, Inc. 1988)
was used to determine whether habitat variables differentiated species and gender
groups within each of three seasons (Winter=January-April, Summer=May-
August, Fall=September-December). Wilks' Lambda scores (p<0.05) were used to
indicate if the total model detected significant differences within seasons because
meaningful patterns could exist even when no individual habitat types exhibited
significant differences in rates of use among species or gender groups. When
differences were indicated by the overall analysis, significant differences among
species within individual habitat types were determined. These frequency data
were used in subsequent factor analyses to help clarify observed patterns of habitat
overlap based on percent frequency occurrence. Factor analysis (SAS Institute,
Inc. 1988) was performed for each sex by season combination (n=6) using habitat
variables that were used regularly by all three species. Mean factor scores were
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
then calculated and plotted for each sex by season combination for factors that
accounted for at least the average amount of model variance.
Habitat use patterns were determined by comparing the percent frequency of
habitat use of individual resident adult study animals with the composition of
concave polygons that encompassed all resident home ranges of each species from
1986 through 1994 (Fig. 3.1). Concave polygons were determined using McPaal
(Stuwe 1985) and were used in order to exclude areas that resident adults did not
use. Thus, areas such as suburban Naples, Florida, were excluded from the habitat
available to resident adults even though dispersers of all three species were
occasionally found in such peripheral range. Chi-square analysis (p=0.05) was
used to compare the composition of concave polygons of a given species (expected
habitat use exhibited by all individuals) with the composition of habitat types
determined from radio telemetry for each individual within that species (observed
habitat use). Although patterns of habitat selection and avoidance have previously
been based on a comparison of used versus available habitat within individual
home ranges (Maehr et al. 1991a), this method presumes that the selection of a
home range is independent of the spatial arrangement of conspecifics and
distribution of landscape features that make up habitat for that particular species.
As was observed among dispersing subadults of all three species, some individuals
traveled widely within the permanently occupied range for that species and
occasionally ventured into areas that were unsuitable for permanent occupation.
Although individuals such as female panther #52 expanded the known breeding
distribution for the species, most dispersal movements resulted in only temporary
occupation outside of the core breeding area.
I examined seasonal home ranges of all adult bobcats (4 males, 4 females), 5
adult male black bears, 5 adult female black bears, 5 adult female panthers, and 5
adult male panthers, and calculated habitat use patterns for each season.
Individuals were selected in order to represent as much of the study area as
possible. Subadults and dispersing individuals were disqualified from these
analyses.
Habitat availability was determined by using 1985-1989 geo-referenced
Landsat Thematic Mapper imagery (Kautz et al. 1993), and SPANS geographic
information system software (TYDAC 1991). Kautz et al. (1993) recognized 22
land cover types, but not all of them were represented in South Florida, and several
could not be consistently differentiated from others with similar reflective qualities.
For example, pine/cabbage palm forests were not distinguishable from pine
flatwoods, cabbage palm woodlands were similar to hardwood hammocks, and
grasslands and dry prairies were not distinguishable from each other. As a result, I
used nine cover types readily distinguishable from each other for chi-square
analyses requiring comparisons of used versus available habitat This classification
is similar to the one used by Maehr et al. (1991a) for the Florida panther, the
principal difference being the inclusion of mangroves as a separate category and
the incorporation of salt marshes into the herbaceous marsh category. The nine
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
cover types recognized include pine flatwoods (PP), hardwood hammock (HH),
mixed swamp (MS), cypress swamp (CS), thicket swamp (TS), herbaceous marsh
(MA), dry prairie (DP), agricultural/disturbed (AD), and mangroves (MG).
Habitat overlap between species was determined by comparing overlap
coefficients based on percent frequencies of seasonal habitat use (Pianka 1986).
Values approaching 1.0 represent maximum similarity in habitat use.
Results and Discussion
The sum total areas of radio-collared, permanent resident adults was 468 km2
for bobcats, 2982 km2 for black bears, and 1735 km2 for Florida panthers (Fig.
3.1). The bobcat polygon was completely contained within the bear and panther
polygons; however, black bear use of coastal areas created a zone of non-overlap
with both cat species. As a result, salt marshes and mangroves were available to
black bears but not to bobcats and panthers.
Bobcats are known to range throughout South Florida and trapping them was
opportunistic, so the polygon for this species certainly underrepresents occupied
range. In other words, this area reflected only that portion of occupied range that
encompassed resident study animals and included gaps between individuals that
were likely used by uncollared bobcats. Because of their smaller home ranges and
the variability inherent in the landscape, each bobcat sampled in this study was
unlikely to experience the plant community diversity that was typical of the larger
species. Thus, this sample is likely insufficient to reflect overall habitat use
patterns for the species in South Florida. Black bears, on the other hand, were
captured over a large area and this, coupled with their larger movements and larger
sample sizes, improved the reliability of generalizations about bear habitat-use
patterns in South Florida. Similarly, the panther polygon represents extensive
capture efforts and contains the core of permanently occupied range (Maehr et al.
1991a; Maehr and Cox 1995). Thus, the estimates of panther and black bear
habitat use are probably more representative of their species than are the estimates
for bobcats.
Florida panthers exhibited little variation in habitat use patterns between
years (Table 3.1). Differences between consecutive years that were significant or
that approached significance for individual panthers were usually related to social
dynamics that influenced home range shape and size. For example, during 1987
and 1988 female panther #09 gradually shifted her home range to the more heavily
forested Fakahatchee Strand as the result of the removal of female panther #08 and
the home range vacancy that was created by this artificial abandonment in April
1987. Male panther #12 exhibited several habitat-use shifts that were related to the
colonizations and deaths of resident males in adjoining home ranges during 1989
and 1991 (Table 3.1) (see home range and land tenure chapter). This
interpretation is supported by the observation that panther #12's use of mixed
swamp declined in those years following a withdrawal from the Fakahatchee
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Strand, a system dominated by this forested wetland. Number 12's final habitat-
use shift that preceded his death in 1994 was apparently related to failing health
and a shrinking home range. While it is possible that differences in panther habitat
use also may be influenced by annually fluctuating food supplies, previous studies
suggest that deer populations have remained stable in space and time in South
Florida (Land et al. 1993) and are thus unlikely to influence panther habitat use.
Female black bears exhibited the greatest variability between years. These
differences were probably related to reproduction and denning when females spend
several months in a restricted area and small cubs restrict their movements.
Although mast supplies were not measured in this study, qualitative comparisons
suggest that concentrations of important foods such as saw palmetto fruit and
acorns changed in spatial distribution annually. Such varying nutritional
opportunities and subsequent movements to access alternative food supplies may
explain the variation in habitat use demonstrated by male black bear M13 (Table
3.1).
Significant differences (p=0.001) in seasonal habitat use patterns were
observed among all species/gender groups for several habitat variables (Tables 3.2
and 3.3). Females tended to differ on more habitat dimensions than males (Table
3.2). Habitats that were used differently by females in all seasons included
hardwood hammock, mixed swamp, and cypress swamp. Habitats that were used
differently by males in all seasons were hardwood hammock and
agricultural/disturbed (Table 3.3). It is likely that female bear and panther habitat
use was influenced by the interrelated effects of smaller home ranges (relative to
males), pregnancy, denning, and dependent young. Localized movements due to
dependent cubs and kittens undoubtedly increased the use of areas near den sites
and reduced the use of more distant preferred habitat that would otherwise have
been used had these females been solitary.
Percent frequency of habitat use based on individual analyses indicate that
forest cover is used by panthers (Table 3.4), black bears (Table 3.5), and bobcats
(Table 3.6) nearly to the exclusion of maritime and unforested cover types (Fig.
3.2). Further, in every season, South Florida's large carnivores used land cover
types in different proportions than they were available (p<0.05) (Table 3.7). This
was due primarily to an avoidance by most individuals of herbaceous or otherwise
unforested habitats. For example, herbaceous marshes covered from 12.8 percent
to 24.0 percent of each habitat availability polygon, yet 3.5 percent was the most
this cover type was used (Table 3.8) by any species/gender group. Pine flatwoods
(including pine/cabbage palm) were universally preferred by all three species in
every season. Bears used hardwood hammock slightly more than it was available,
whereas male bobcats exhibited a marginal aversion to this cover type. The latter
may be a consequence of the small sample size, because male bobcat M02 used
hardwood hammock in proportions more than twice its availability (Table 3.6).
Cypress swamps appeared to be used less than available by all species, while
mixed swamp, a more thickly vegetated plant community, was used in varying
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
proportions by study animals. Bobcats appeared to avoid mixed swamp
communities, which were not abundant in the bobcat habitat availability polygon.
Most mixed swamp in Florida is found in the Fakahatchee Strand, where panthers
have resided at least since field searches were first conducted (Nowak and McBride
1973). This cover type was used slightly more than it was available to panthers,
even though nutrition may be a problem for some individuals that reside there
(Maehr et al. 1989a). Black bears, especially females that were known to establish
dens in this cover type, also used mixed swamp in a higher proportion than it
occurred in the environment Further, important black bear foods, such as Thalia
geniculata, and early mast-producing shrubs such as swamp dogwood were
abundant in the Fakahatchee Strand.
Two components common to the six habitats that were used regularly by all
three species explained more than an average amount of variation in habitat use
during each season (Table 3.9). Among these habitats, pine flatwoods accounted
for the least variation, suggesting that it was used consistently by all of South
Florida's large carnivores (Table 3.10). The greatest variability during summer,
however, was related to differential use of pine flatwoods and hardwood
hammocks. Hammocks tended to be used more by female bobcats during summer
than during other seasons and by male panthers during every season. The
disproportionately high use of this habitat by male panthers and female bobcats
may explain the consistent divergence between male and female panthers
throughout the year and between male and female bobcats during summer. The
conclusion of apparent differences between bobcat gender should be tempered,
however, because of small sample size. On the other hand, Maehr and Cox (1995)
noted that similar trends in male panther preferences for hardwood hammock may
represent resource partitioning that reduces the potential for competition between
male and female panthers. The panther was the only species that exhibited
consistent divergence in seasonal habitat-use across seasons (Fig. 3.3). Although
food habits studies have not demonstrated differences related to gender (Maehr et
al. 1990), Harlow (1959) found that hardwood hammocks were the most productive
habitats for white-tailed deer, and sign of wild hogs is more frequently encountered
in this habitat type than elsewhere (pers. observ.). If male panthers use hardwood
hammocks disproportionately because larger prey are more available in this upland
plant community, this may represent the causal mechanism that facilitates niche
separation between male and female panthers. Such a pattern was not consistently
found in the other two species.
Overall, considerable habitat overlap among species was apparent, but male
and female panthers exhibited more niche separation than bears or bobcats, and
panthers differed more by gender within species during summer than with the
other species. When compared to panthers, bobcats and black bears exhibited more
within-species similarity, suggesting that gender had less influence on habitat use-
patterns for these species. If seasonal habitat shifts were made, both sexes
experienced them. In general, panthers used pine flatwoods and hardwood
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
hammocks more than was expected based on their availability in the landscape,
whereas cypress swamp, thicket swamp, freshwater marsh, grasslands, and
agricultural areas were used less than expected (Table 3.8). These findings also
support the conclusions of Maehr et al. (1991a) that all panthers prefer upland
forests. A reduction in bear use of mixed swamp and an increase in the use of pine
flatwoods during fall was probably related to the wide-ranging excursions that
many bears undertook to access abundant supplies of saw palmetto fruit Black
bears also used agricultural/disturbed areas more than expected from mere
abundance in the landscape. This likely was due to the abundance of Brazilian
pepper thickets that often are associated with disturbed sites and agricultural edges.
Brazilian pepper thickets frequently replace agricultural fields when they are
abandoned, and this species is a common colonizer of roadsides, ditchbanks, and
spoil (Loope and Dunevitz 1981; Ewel et al. 1982; Abrahamson and Hartnett
1990).
Black bears were the only species observed to utilize mangrove forests.
Although use of maritime habitats by bears occurred year-round, the only activity
that could be confirmed in these coastal swamps was denning by adult females.
Male bears used mangroves proportionally less than their availability while females
used this cover type proportional to availability. Perhaps mangroves are more
important for cover than for the procurement of food, although black bears likely
obtained some foods in mangroves. Foods that draw non-denning black bears to
mangroves remain unidentified. The densely branched growth form of mangroves,
often dense swarms of mosquitoes, and deep organic soils make these areas nearly
impenetrable to humans and other South Florida cursorial mammals. Extensive
impenetrable areas made up of Rhododendron spp. and Smilax spp. are similarly
impenetrable and are typical in much of the black bear's inhabited range (Pelton
1982:507). Despite the avoidance of unforested habitats by black bears, herbaceous
wetlands adjacent to large mixed swamps and mangrove forests occasionally were
used to obtain nutritious foods, such as the nest-building colonial ant
Crematogaster (see dietary overlap chapter). An avoidance of mangroves by
panthers was also observed by Smith and Bass (1994) in Everglades National Park,
an area where forested cover is sparse relative to forb- and sedge-dominated
communities.
Even though Foster (1992) observed that the bobcats in her study sample were
frequently found in mixed swamp, the sample in either study may not have been
representative of the population. However, both studies were similar in
demonstrating individual preferences for pine flatwoods that exceeded 60 percent
(Foster 1992:72) (Table 3.6). Thicket swamps and freshwater marshes were used
less than expected by bobcats in this study, while grasslands and
agricultural/disturbed habitats were used to varying degrees in inconsistent
seasonal patterns that may reflect individual variation among bobcats or small
sample size.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
Saw palmetto thickets appear to be universally important to bobcats in South
Florida. Foster (1992) suggested that this common pine flatwoods understory plant
was preferred, and Wassmer et al. (1988) found that saw palmetto thickets were
important as natal dens. Female bobcat F03 denned in a palmetto thicket in the
Bear Island Unit of the Big Cypress National Preserve during 1987, as did a female
in Foster's (1992) study. Although Foster (1992) found that bobcats avoided
agricultural areas, I found that male bobcats exhibited seasonally variable use of
this cover type that exceeded its availability (Table 3.6). Wassmer et al. (1988)
found that male bobcats used several agricultural cover types more frequently than
expected even though citrus groves were avoided.
Capture locations of resident adult bobcats no doubt can bias subsequent
interpretations of habitat use. Most animals Foster (1992) studied were captured
within the centers of large tracts of public lands, whereas several of the animals in
this study originated from private lands that bordered or included agricultural
fields. Panthers and black bears were captured at widely scattered sites, and they
were found to move long distances compared to the relatively sedentary bobcats
with smaller home ranges. Thus, by virtue of their smaller spatial requirements,
bobcats captured on public lands were less likely to utilize agricultural habitats on
adjacent private land. Unlike black bears and panthers, bobcats in this study did
not demonstrate a consistent preference for hardwood hammocks; in fact, this
cover type was used in lower proportions than its availability during all seasons by
males and during fall by females. It is possible that the generally more open
understory of hammocks may not provide the cover conditions that are typically
found in pine flatwoods that contain saw palmetto. The more solid canopy
associated with live oak and cabbage palm hammocks creates shaded conditions at
ground level that tend to reduce saw palmetto density. Snyder et al. (1990) did not
list saw palmetto as a common understory species in South Florida hammocks
although it is found in every variation of this plant community. In addition, Loope
and Urban (1980) found that saw palmetto occurred in only 2 of 100 tropical
hardwood hammocks in Everglades National Park. The consistency with which
saw palmetto was used by bobcats in this as well as other studies (Wassmer et al.
1988; Foster 1992) suggests this is a very important component of bobcat habitat.
Measurements of dietary overlap indicated little likelihood of competition
between any of South Florida's native carnivores. This was not the pattern,
however, for measurements of habitat partitioning (Pianka 1986). While males
and females from the same species usually exhibited close habitat affinities, black
bears showed the least (0.75-0.87) similarities between gender (Table 3.11). Male
and female panthers exhibited overlap exceeding 0.90 in all seasons and portrayed
a higher level of similarity than was suggested by factor analyses. Overlap ranged
from a minimum of 0.49 between female bobcats and female black bears during
winter, to a maximum of 0.96 between male panthers and female black bears
during winter. Although few patterns were consistent in this analysis, and they did
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
not universally agree with factor analyses, measurements based on the Pianka
(1986) algorithm clearly demonstrated a high level of habitat overlap within this
group of species. A predominantly vegetarian diet, different activity patterns, and
winter denning allowed black bears to be involved in more high habitat overlap
combinations than pairings between bobcats and panthers, which exhibited higher
dietary overlap (see dietary overlap chapter). When gender was ignored, however,
the importance of upland forests, and inland swamps to South Florida's large
mammalian carnivores is obvious (Fig. 3.4).
The habitat overlap analysis (Table 3.11) supports the results of the factor
analysis where some pairings of sympatric species exhibited greater overlap than
between genders within species. For example, female black bear habitat use was
more similar to female panther habitat use during fall (0.965) than it was to male
black bears (0.875). Some habitat use differences within species may be the
product of evolutionary divergence that has reduced competition between the sexes.
Sexual dimorphism occurs in all three species which, when combined with the
behavior-altering influence of reproduction, may help to explain the observed
patterns in habitat separation within species. While gender-dependent prey
selection in bobcats and panthers may not be as dramatic as that reported in
weasels (Mustela spp., Hall 1951; Lockie 1966; Erlinge 1974), and several bird
species (Darwin 1871:208; Storer 1955; Selander 1966), even slight differences in
prey selection may dampen the effects of periodic prey scarcity or allow the
predator's population to increase during times of prey abundance. Prey selection
differences between male and female bears are likely insignificant despite their
high degree of sexual dimorphism. Differences in food habits among South
Florida's native carnivores may be sufficient to trivialize the extensive habitat
overlap that they demonstrate. But for the two cat species in South Florida, prey
selection may be an important factor explaining the differences in habitat use
between the sexes.
Table 3.1. Annual habitat use comparisons for black bears and Florida panthers monitored for multiple years using Chi-square analysis
(p=0.05). Probabilities in bold face represent significant differences between individual habitat use in one year versus the previous year.
Habitat tpe'
ID#
MG Al p
Year PP HH MS CS TS MA DP AD
Female panther
1986 19.6 20.9 34.8 12.9 1.1 0 0.6 0
1987 12.0 38.7 40.8 7.7 0 0 0.7 0
1988 7.6 26.7 46.5 19.1 0 0 0 0
1989 3.7 16.1 52.8 26.7 0.6 0 0 0
1990 7.0 20.5 59.0 12.2 0.6 0.6 0 0
1991 11.5 26.6 52.5 8.6 0 0 0 0.7
1992 16.6 24.7 53.3 6.7 0 0.7 0 0
1993 12.2 23.0 56.1 8.8 0 0 0 0
1994 11.0 18.1 67.7 3.1 0 0 0 0
1990 30.7 24.3 7.1 37.9 0 0 0 0
1991 43.7 24.3 9.0 22.9 0 0 0 0
1992 54.7 22.0 10.7 12.7 0 0 0 0
1993 50.7 14.9 10.1 243 0 0 0 0
1994 47.6 25.8 14.5 12.1 0 0 0 0
Male panthers
1986 26.5 39.1 22.3 11.4 0.6 0 0 0
1987 32.1 22.6 29.8 14.9 0 0 0 0.6
1988 17.4 23.9 34.2 23.2 0.6 0.6 0 0
1989 19.9 27.7 16.3 30.1 5.4 0 0.6 0
1990 21.9 25.6 21.2 28.7 1.9 0 0 0.6
1991 28.7 40.7 14.7 15.3 0 0 0 0
1992 24.5 37.7 14.6 22.5 0.7 0 0 0
1993 32.4 42.7 13.8 10.3 0.7 0 0 0
1994 37.4 48.7 7.3 5.7 0.8 0 0 0
1987 32.9 36.2 14.1 14.1 0 0 2.7 0
1988 29.7 44.9 5.7 19.6 0 0 0 0
1989 28.4 45.8 7.1 16.8 1.3 0 0.6 0
S 10.0
S 9.1
- 6.2
S 7.9
S 4.7
S 2.6
1.8
4.5
6.2
4.4
5.2
7.9
- 7.7
- 8.3
S 12.7
S 3.7
S 12.1
- 2.5
- 5.9
S 4.1
8.2
2.3
Table 3.1. (continued)
Habitat twel
ID# Year PP HH ..MS CS MA DP AD .....MG
Female black bears
F02 1992 50.6 25.9 7.4 12.3 1.2 1.2 0 1.2 0
F02 1993 22.4 30.2 21.0 18.4 1.3 0 0 6.6 0 23.9 00005
F02 1994 15.5 21.8 6.2 23.4 10.9 0 0 21.9 0 27.0 <0.0001
F03 1993 5.3 20.0 56.0 16.0 0 0 0 2.7 0 -
F03 1994 12.5 26.5 50.0 7.8 1.6 1.6 0 0 0 12.9 0.04
F09 1992 12.2 19.5 2.4 8.5 3.7 3.7 0 3.7 46.3
F09 1993 16.9 19.7 4.2 7.0 4.2 2.8 0 1.4 43.7 2.7 0.91
F19 1993 26.7 32.0 24.0 8.0 6.7 2.7 0 0 0
F19 1994 21.2 30.3 43.9 3.0 0 1.5 0 0 0 8.8 0.26
Male black bean
M02 1991 7.3 35.3 4.4 2.9 8.8 8.8 0 0 32.3
M02 1992 6.3 30.4 8.9 1.3 6.3 15.2 0 3.8 27.8 8.8 0.26
M08 1992 24.7 9.1 14.3 46.7 2.6 1.3 0 1.3 0
M08 1993 25.9 6.5 9.1 46.7 0 1.3 0 10.4 0 11.3 0.08
M13 1992 33.7 15.0 3.7 18.7 0 0 0 27.5 1.2
M13 1993 39.7 9.6 8.2 12.3 9.6 1.4 0 6.8 12.3 37.3 <0.0001
M13 1994 35.2 25.9 13.0 9.3 1.8 1.8 0 13.0 0 28.9 <0.0001
M18 1992 42.6 8.8 22.1 11.8 2.9 1.5 1.5 5.9 2.9
MIS 1993 47.7 8.9 14.9 9.0 7.5 1.5 1.5 9.0 0 7.6 0.47
'PP-plimwe/lmatto. wood hmmowd MSmcixed -mo CS-yp m TSw-ickM snp. MA-teash -ad usl mar DP-y paie
AD-@ig-,unditurbed MGma-rove
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
Table 3.2. Habitat use differences among female bobcats, black bears and panthers in South Florida as
determined by multiple analysis of variance (p=0.05) of habitat use frequencies. Only those habitats that
indicated significant differences are rooted.
Winter
Wilks' Lambda=0.0594 F=6.2 p-0.0001
Habitattype F p
Hardwood hammock 12.44 0.0001
Cabbage palm 5.17 0.0113
Mixed swamp 4.05 0.027
Cypress swamp 6.40 0.0046
Herbaceous marsh 3.79 0.0333
Mangrove 3.35 0.048
Summer
Wilks' Lambda=0.0556 F=5.67 p0.0001
...Habitatt F p.F
Pine flatwoods 3.47 0.0433
Pine/cabbage palm 4.17 0.0247
Hardwood hammock 16.97 0.0001
Mixed swamp 3.65 0.0374
Cypress swamp 5.40 0.0095
Dry prairie/grassland 6.57 0.0041
Fall
Wilks' Lambda=0.0585 F=6.00 p~0.0001
...Hitat .......... .... F .... ....... ...
Pine/cabbage palm 13.35 0.0001
Hardwood hammock 7.35 0.0022
Cabbage palm 5.78 0.0069
Mixed swamp 6.82 0.0032
Cypress swamp 6.26 0.0049
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Table 3.3. Habitat use differences among male bobcats, black bears and panthers in South Florida as
determined by multiple analysis of variance (p=0.05) of habitat use frequencies. Only those habitats that
indicated significant differences are reported
Winter
Wilks' Lambda0.1064 F=3.443 p=0.0003
Habitat type F
Pine flatwoods 5.14 0.0118
Hardwood hammock 17.00 0.0001
Mixed swamp 6.34 0.0049
Aricultural/disturbed 5.29 0.0106
Summer
Wilks' Lambda=0.012 F=9.665 p=0.0001
Habitat ... F p......... ..
Pine flatwoods 4.15 0.0279
Pine/cabbage palm 3.77 0.0370
Hardwood hammock 11.74 0.0003
Agricultural/disturbed 3.61 0.0421
Fall
Wilks' Lambda=0.143 F=2.684 p=-0.0041
HabitatXty Fp ____
.... ......-.. .....t F e..............
Pine/cabbage palm 4.36 0.0225
Hardwood hammock 11.67 0.0002
Mixed swamp 3.50 0.0440
Aricultural/disturbed 5.29 0.0113
00
Table 3.4. Seasonal habitat use by Florida panthers (percent frequency) 1986-1994. Abbreviations are: PP=pine flatwoods,
HH=hardwood hammock, MS=mixed swamp CScypres swamp, TS=hidckt swamp, MA-feshwater and saltwater mars, DP--ry
prairieand grassland, ADaricultural/disturbed, and MG=mangoves.
ID# Sex Season Year PP HH MS CS TS MA DP AD MGo
09 F W 1986 14 29 34 21 2 0 0 0
11 F W 1986 30 5 8 8 0 0 0 0
19 F W 1992 39 24 16 18 0 0 0 2
31 F W 1993 51 31 4 10 2 0 0 2
32 F W 1992 20 20 33 26 0 0 0 0
09 F S 1986 17 25 51 5 2 0 0 0
11 F S 1986 31 54 9 3 2 0 0 0
19 F S 1992 22 26 16 36 0 0 0 0
31 F S 1993 27 19 10 37 4 2 0 0
32 F S 1992 44 19 17 19 0 0 0 0
09 F F 1986 28 39 18 12 0 0 2 0
11 F F 1986 30 32 17 20 0 0 0 0
19 F F 1992 40 34 14 12 0 0 0 0
31 F F 1993 42 18 16 14 6 0 0 4
32 F F 1992 37 37 10 14 0 0 0 2
12 M W 1986 22 38 27 13 0 0 0 0
13 M W 1987 27 46 15 3 5 0 2 0 -
26 M W 1993 53 28 6 12 0 0 0 0
46 M W 1993 23 58 4 12 2 0 0 0 -
51 M W 1994 31 13 36 14 0 0 0 0
12 M S 1986 19 51 21 9 0 0 0 0
13 M S 1987 26 41 13 9 0 4 6 0
26 M S 1993 47 36 6 13 0 0 0 0
46 M S 1993 23 47 6 21 2 0 0 0
51 M S 1994 22 18 53 6 0 0 0 0
12 M F 1986 39 28 18 13 2 0 0 0
13 M F 1987 42 37 4 16 0 0 0 0
26 M F 1993 51 33 8 8 0 0 0 0
46 M F 1993 27 57 2 12 0 2 0 0
51 M F 1994 43 43 14 0 0 0 0 0 -
s covr type wa not avaab to aihTduraidat individmbm ifhe sy A
Table 3.5. Seasonal habitat use by south Florida black bears (percent frequency), 1991-1993. Abbreviations are: PP-pine flatwoods,
HH=hardwood hammock, MS=mixed swamp, CS=cypress swamp, TS=thicket swamp, MA=freshwater and saltwater marsh, DP-dry
pririe and grassland, AD=agicultural/disturbed, and MG=mangrve.
I# Sex Season Year PP HH MS CS TS MA DP AD. M.....
F02 F W 1992 73 23 0 0 3 0 0 0 0
F03 F W 1993 0 0 83 17 0 0 0 0 0
F04 F W 1992 3 26 42 22 6 0 0 0 0
FO0 F W 1992 0 12 4 0 4 0 0 4 75
F06 F W 1992 55 34 0 3 0 0 0 7 0
F02 F S 1992 23 15 31 8 11 11 0 0 0
F03 F S 1993 4 8 67 12 0 0 0 8 0
F04 F S 1992 8 32 40 20 0 0 0 0 0
F05 F S 1992 0 8 0 0 0 4 0 4 75
F06 F S 1992 41 30 7 22 0 0 0 0 0 m
F02 F F 1992 36 16 12 28 0 4 0 4 0
F03 F F 1993 11 48 22 18 0 0 0 0 0
F04 F F 1992 42 12 33 12 0 0 0 0 0
F05 F F 1992 15 15 4 4 0 0 0 15 46
F06 F F 1992 69 11 8 11 0 0 0 0 0
M06 M W 1991 36 27 18 9 0 0 0 9 0
M08 M W 1992 7 3 17 62 7 0 0 1 0
M13 M W 1993 25 0 0 4 29 4 0 12 25
M18 M W 1992 16 16 21 10 5 0 0 21 10
M20 M W 1993 74 13 4 9 0 0 0 0 0
M06 M S 1992 7 36 36 0 0 0 0 21 0
M08 M S 1992 25 12 17 46 0 0 0 0 0
M13 M S 1993 26 17 22 26 0 0 0 0 9
M18 M S 1992 23 4 38 23 4 4 4 0 0
M20 M S 1993 32 23 9 32 4 0 0 0 0
M06 M F 1992 26 13 43 13 0 4 0 0 0
M08 M F 1992 50 14 9 32 0 4 0 0 0
M13 M F 1993 65 11 4 8 0 0 0 8 4
MIS M F 1992 87 9 4 0 0 0 0 0 0
M20 M F 1993 40 40 4 4 4 8 0 0 0
Table 3.6. Seasonal habitat use by south Florida bobcats (percent frequency) 1986-1987. Abbreviations re: PP=pine flatwoods,
HH=hardwood hammock, MS=mixed swamp, CS=cypress swamp, TS=thicket swamp, MA=firshwater and saltwater marh DP-dry
p erie and grassland, A riculural/ditubed, and MG-manOves.
ID# Sex
F03 F
F06 F
F07 F
F03 F
F06 F
F07 F
F09 F
F03 F
F06 F
F07 F
M01 M
M02 M
MOS M
M08 M
M01 M
M02 M
M08 M
M01 M
M02 M
MO5 M
M08 M
Season
W
W
W
S
S
S
S
F
F
F
W
W
W
W
S
S
S
F
F
F
F
Year PP
1986 64
1987 64
1987 64
1986 72
1987 23
1987 65
1987 40
1986 83
1987 40
1987 22
1986 88
1986 45
1987 77
1987 36
1986 76
1986 67
1987 0
1986 87
1986 46
1986 68
1987 28
HH MS CS TS MA DP AD MG
... ....
'This cove typ wasu not avUl to adut raident ividusy n mte sudy *a.
~~___
-
- --
Thia mve type wm net avsflabk to tdua nulmt m the study M .
Table 3.7. Chi-square values and probabilities for seasonal comparisons between habitat available to and habitat used by large carnivores
in south Florida, 1986-1994.
Winter Summer Fall
Species Sex ID# Ci p Chi p Ci p
Panther
Panther
Panther
Panther
Panther
Panther
Panther
Panther
Panther
Panther
Bear
Bear
Bear
Bear
Bear
Bear
Bear
Bear
Bear
Bear
Bobcat
Bobcat
Bobcat
Bobcat
Bobcat
Bobcat
Bobcat
Bobcat
57.6
59.9
54.5
75.1
53.3
67.7
81.5
76.4
77.6
66.8
140.5
128.5
77.8
106.5
126.8
95.1
65.8
106.2
72.9
113.9
90.4
121.0
87.7
133.5
89.7
137.2
97.0
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
88.0
92.0
45.3
38.6
60.6
77.3
49.9
75.7
60.4
87.8
77.3
49.9
75.7
60.4
87.8
71.4
106.7
78.7
102.5
79.0
95.5
81.6
90.0
113.4
107.6
92.2
53.1
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
62.0
56.6
70.1
57.4
62.5
65.4
71.0
82.6
77.5
12.6
59.8
77.9
97.5
82.5
106.4
81.2
69.6
103.5
145.8
89.2
128.2
123.8
89.1
153.4
114.7
102.1
104.2
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.013
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
Table 3.8. Comparion between habitat available and mean habitat use for south Florida carnivores, 1986-1994.
Habitat tvne
Season PP HH MS CS S MA DP AD MG
Sex/species
Female panthers
Available
Used
Used
Used
Male panthers
Available
Used
Used
Used
Female bears
Available
Used
Used
Used
Male bears
Available
Used
Used
Used
Female bobcats
Available
Used
Used
Used
Male bobcats
Available
Used
Used
Used
Winter
Summer
Fall
Winter
Summer
Fall
5-
Winter
Summer
Fall
Winter
Summer
Fall
Winter
Summer
Fall
Winter
Summer
Fall
11.8 12.6 .9 313
30.8 31.6 19.0 16.6
28.2 28.6 20.6 20.0
35.4 32.0 15.0 14.4
11.8 12.6 &9 31.3
31.2 36.6 17.6 10.8
27.4 38.6 19.8 11.6
40.4 39.6 9.2 7.8
4.8 11.9 59 30.3
26.2 19.0 25.8 8.4
15.2 18.6 29.0 12.4
34.6 20.4 15.8 14.6
4.8 11.9 59 30.3
31.6 11.8 12.0 18.8
22.6 18.4 24.0 25.4
53.6 17.4 12.8 11.4
6.5 20.3 11.4 32.4
64.0 25.0 0 24.5
50.0 36.0 0.6 10.0
483 11.3 0 15.7
6.5 20.3 11.4 32.4
61.5 12.7 5.5 9.2
47.7 11.0 10.0 11.7
57.2 17.0 0 10.5
12.8 13.5
0 0
0.4 0
0 0.4
12. 13.5
0 0.4
0.8 1.2
0.4 0
24.0 13
0 0
3.0 0
0.8 0
24.0 1.3
0.8 0
0.8 0.8
3.2 0
22.6 2.7
3.5 0
0 3.5
0 20.7
22.6 2.7
0 0
0.7 0
0 13.2
'1Ib habitat type was not available to bobcs or pntem.
'~'~'~~'~'~""'~'~~~~~~~~~~'~"
0.7 14.1
2.2 15.0
2.4 15.0
3.8 9.2
0.7 14.1
8.6 7.0
4.2 1.8
1.6 0.8
0.5
0
0
3.7
0.5
9.0
16.7
1.5
t.rt s hsbltat type wu not avtlbk to bebcm penthen.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Table 3.9. Eigenvalues and proportions of variability explained by each of 5 factors that examine habitat use
patterns in bobcats, black bears, and Florida panthers in Southwest Florida.
Factor
Winter I II II IV V
Eigenvalue 1.6752 1.5173 0.992 0.7164 0.5978
Proportion 0.28 0.25 0.16 0.12 0.10
Summer
Eigenvalue 1.9756 1.2576 0.9351 0.823 0.6394
Proportion 0.33 0.21 0.15 0.14 0.11
Fall
Eigenvalue 1.9572 1.4794 0.9155 0.6399 0.562
portion 0.33 0.25 0.15 0.11 0.09
Table 3.10. Pearson correlation coeficients for habitat variables used by large mammalian carnivores in southwest Florida. Underlined
values are significantly correlated with the observed variability in habitat use among bobcats, black bear, and Florida panthers. Values in
parentheses are the probability that the habitat variable is not correlated with the observed variability
Habitattype
Cabbage Hardwood
Pine flatwoods palm/pine hammock Cabbage palm Mixed swamp Cypress swamp
Winter
Factor I 0.49732 0.95275 0.96874 0.87926 0.93048 0.89386
(0.3155) (0.0033) (00015) 0.0210 0.0071) .0163)
Factor n -0.49273 035626 0.28344 0.82741 0.70942 0.76051
(0.3207) (0.4882) (0.5862) (0.0421) (0.1144) (0.0792)
Summer
Factor I 0.98865 0.87446 0.27489 0.44129 -0.26426 0.05092
(0.0002) (0.0227) (0.5981) (0.3810) (0.6128) (0.9237)
Factor n 0.25913 0.18144 0.89598 0.61557 0.70703 0.57216
(0.620) (0.7308) (0.0157 (0.1933) (0.1162) (0.2354)
Fall
Factor -0.05268 0.97957 0.86621 0.90044 0.99509 0.96325
(0.921) .006) (0026) (0.0144) (.0001) (0.002)
Factor n 0.59210 0.70811 0.85509 0.26351 0.57605 0.70681
(0.2156) (0.1154) (0.030) (0.6139) (0.2315) (0.1163)
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Table 3.11. Seasonal habitat overlap (Pianka 1986) among large mammalian carnivores in South Florida.
Values appraing 1.0 reflect highly similar habitat use patterns.
Sex/species F Bear M Bear F Bobcat M Bobcat F Panther M Panther
Winter
FBear 1
MBear .815 1
FBobcat .492 .723 1
M Bobcat .500 .639 .939 1
F Panther .800 .850 .630 .553 1
M Panther .697 .666 .690 .611 .907 1
Summer
............................................................................... ......
FBear 1
MBear .751 1
FBobcat .562 .749 1
MBobcat .514 .685 .801 1
F Panther .845 .677 .591 .718 1
MPanther .725 .783 .740 .850 .945 1
Fall
FBear 1
M Bear .875 1
F Bobcat .767 .913 1
M Bobcat .842 .955 .897 1
F Panther .965 .789 .671 .636 1
MPanther .960 .803 .696 .749 .957 1
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
AREAS USED TO CALCUALTE
HABITAT AVAILABLE TO
RESIDENT ADULT STUDY ANIMALS
2,20 IMMOKALEE 0
2,900
1 75 / *
0 4 8
ca
2,860 0 CHOKOLOSKEE
S40
2.840 ^
) 480
EW UTM
Figure 3.1. Concave polygons for black bear, bobcat, and Florida panther habitat analyses. Species polygons
encompass all resident home ranges of adults studied from 1986 to 1994.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
FEMALE PANTHERS
100
80^^^^^
FEMALE BOBCATS
MALE PANTHERS
MALE BOBCATS
MALE BLACK BEARS
WINTER SUMMER FALL
SMS CS n AD Q MG
Figure 3.2. Seasonal habitat-use trends for female and male black bears, bobcats, and Florida panther in
South Florida, 1986 1994. PP= pine flatwoods, PC= pine cabbage palm, HH= hardwood hammock, CA=
cabbage palm, MS= mixed swamp, CS= cypress swamp, AD= agricultural/disturbed, MG= mangrove
swamp.
S 0
z
: 100
W 80
V)
L 60
Uw 40
40
3 20
I--
<0
m
4 100
x
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
UL.
04 WINTER F
0.2 F /
-0.2
M
.-OA M
-0.6 F
-0.0
.1.5 1 0.5 0 0.6 1 1.5
0.6
0 SUMMER F4
44
tO
*.0.2 M
-0.8---------------
-0A
0.6 Fi ........ M
,1 -0.6 0 0.6 1.
FALL M4
06
0.4
M 0.2
0 M
6-0.2 3 ,
OA F
-0.8 F
.0. I
.0.6 --- -- --- -- --- --
-1.5 -1 -0.6 0 0. 1 1.6
FaMte' 1
Boboem BIlak ban Pmitom
0 0
Figure 3.3. Factor analysis of habitat use patterns among female and male bobcats, black bears, and Florida
panthers in South Florida.
60
50
20
140
IL
1_30
____ iiir-- -nY i III -- I l " I
HaM Type PP HH MS CS TS MA DP AD MG
Panhr M 32 30 17 14.0 1.0 0.3 03 0.3 0
Bobod 550O 160 3.0 1L.0 04 04 &0 4.0 40
Black be 31.0 1.0 200 150 310 1A 0.0 4.0 0
Figure 3.4. Annual habitat use patterns irrespective of gender and season for large mammalian carnivores in South Florida.
See Figure 3.2 for habitat definitions.
-,~ocnf Ir
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
4. HABITAT PATTERN AROUND
FLORIDA PANTHER NATAL DENS AND
BLACK BEAR WINTER DENS
Natural history studies of Florida panther and black bear in South Florida
have examined habitat use (Belden et al. 1988; Maehr et al. 1991a; Maehr et al.
1992), food habits ( Maehr et al. 1990a), dispersal (Maehr et al. 1988), mass
growth (Maehr and Moore 1992), and activity (Machr et al. 1990b). Some aspects
of female panther reproductive behavior were described by Maehr et al. (1989a,
1989b), but habitat descriptions of natal dens were limited to qualitative
comparisons with day-use sites. There is a paucity of published literature
pertaining to black bear ecology in South Florida. Given the importance of
reproduction to population growth and stability in panthers (Maehr and Caddick
1995) and other large carnivores (Caughley and Sinclair 1994), a better
understanding of natal den selection is important for promoting improved
management practices in occupied panther range, in assessing reintroduction sites,
and in managing habitat for black bears. This chapter describes the habitat
characteristics at Florida panther natal dens and black bear winter dens, and
examines the landscape context surrounding these critically important areas.
Methods
Denning of panthers coincided with parturition and was predicted to occur
approximately 90 days after an interaction with an adult male, or denning behavior
was signaled by sharply restricted movements to localized parts of their home
ranges. Black bear denning was indicated by repeated locations of an individual at
one site during the four-month period, January-April. Panther natal dens were
examined after females abandoned these sites with their two-month-old kittens, or
when kittens were less than two weeks of age and the female was known to be
away from the den. Winter black bear den locations were determined by radio
telemetry, and some were examined for evidence of reproduction and for
documenting habitat characteristics.
SPANS geographic information system (GIS) software (Tydac 1991) was
used to analyze habitat variables derived from Thematic Mapper 30 m Landsat
imagery. The application of these data to a variety of Florida wildlife species was
described by Cox et al. (1994) and was used to develop a statewide strategy for
conserving wildlife habitat in Florida. Coverage of vegetation was examined
within 100 m, 500 m, 1000 m, and 5000 m radius circles around both winter and
natal dens. Chi-square contingency tables (p=0.05) were used to evaluate
differences in habitat distribution between 100-m- and 1000-m-radius circles
around dens, and to evaluate the null hypothesis that habitat composition did not
change with increased radius around den sites. Analysis of variance was used to
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
examine differences in the amount of forested habitat within the four distance
zones around each den. When a significant difference (p<0.05) was found,
Duncan's multiple range test (p=0.05) was used to differentiate means. Distances
from dens to the nearest paved road were measured using SPANS. These were
then compared with an equal number of radio locations randomly selected from
within the home range of each study animal during the year that denning was
documented. Because black bears do not leave natal dens during winter, telemetry
locations collected during the months of January-April were eliminated from the
selection of random locations because most coordinates for this time period would
be the den itself.
Results and Discussion
Habitat composition around 31 den sites was examined for 11 female Florida
panthers between 1986 and 1995, 16 den sites of 13 adult female black bears
between 1992 and 1994, and 8 den sites of 6 male black bears between 1992 and
1993. Although one Florida panther (#11) and one black bear (F03) were known
to reuse a den site, none of the other individuals in this study exhibited loyalty to a
single location. Thus, such biases likely had little influence on the independence
of the sample. Dens of most panthers (67%) were located in thickets of saw
palmetto (Maehr et al. 1990b), or they were found in mixed swamp vegetation and
hardwood hammocks. When occurring in these situations, den sites were hidden
by thick ferns or saw palmetto, respectively. Virtually all panther dens were
located within the area of 'highest probability' habitat as described by Maehr and
Cox (1995:1014) and described as the habitat core in the concluding chapter.
None of the black bear dens was found in hardwood hammocks, but female bears
used mangroves for denning. Most (58%) of the black bear dens were located in
either pine flatwoods with a saw palmetto understory, or they were in mixed
swamp vegetation. In the latter situation, elevated tree stumps, naturally low water
conditions, or artificial drainage provided dry den sites.
Descriptions of cougar dens in North America are sparse. None of five recent
ecological studies of cougars described natal den habitat although descriptions of
neonate kittens were made (Anderson 1983; Ashman et al. 1983; Hopkins 1989;
Sweanor 1990; Jalkotzy et al. 1992). Dixon (1982:714), however, suggested that
cougar natal areas were "rather simple den sites..., with only enough cover to keep
out heavy rain and the hot sun." In mountainous settings they tend to be located in
rocky cover whereas thick vegetation is used elsewhere (Dixon 1982). According
to this definition, Florida panther natal dens are typical of non-mountainous
settings.
Black bears utilize a wide variety of structures for winter dens, ranging from
snow ledges, rock caverns, hollow trees, ground excavations, elevated tussocks,
hollow logs, thick brush, bare ground, and even beneath cabins (Willey 1978; Beck
1991; Erickson 1964; Jonkel and Cowan 1971; Johnson and Pelton 1979; Hellgren
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
and Vaughan 1989; Hamilton and Marchinton 1980; Wooding and Hardisky 1992;
Kolenosky and Strathear 1987; Beecham et al. 1983; Hellgren and Vaughan
1989). Although Lindzey and Meslow (1976a) found that aspect did not influence
den selection, several studies in mountainous areas have found that elevation,
prevailing wind, and aspect were important to den selection in mountainous areas
(LeCount 1983; Schwartz et al. 1987; Mack 1990). In some areas, excavated dens
had sealed entrances (Kolenosky and Strathearn 1987). In South Florida, only one
natal den located in the stump of a hollow cypress provided a barrier to wind or
observation and was the only den repeatedly used by the same female for
subsequent litters. All others were located on the ground within a clump of
vegetation.
Contingency tables indicated that significant differences existed in habitat
distribution between 100 m and 1000 m distances around 87 percent of panther
natal dens (Table 4.1). Similarly, the majority (79 percent) of black bear dens
exhibited differences in habitat distribution between 100 m and 1000 m distances
around dens (Tables 4.2 and 4.3). However, a subset of six maps created from
these analyses misrepresented several cover types. This stemmed from the inability
of SPANS to differentiate some forested habitats, so further analyses combined all
forest cover into one class in order to minimize this bias. The method of land-
cover analysis used by Cox et al. (1994) was sufficient to describe large-scale
patterns in wildlife habitat from a statewide perspective and is a valuable tool for
illustrating these patterns. However, when the same satellite image was used to
describe habitat patterns at the finer scale in this analysis, inconsistencies in the
data were magnified. Although this precluded further analysis to determine key
landscape variables based on specific plant communities, Maehr and Cox (1995)
found that distribution of forest cover, regardless of forest type, was correlated with
the distribution of radio telemetry locations of all panthers in South Florida.
A significant difference (F=18.8, p<0.001) was found among the means of
percent forest cover between 100 m, 500 m, 1000 m, and 5000 m radius circles
around all panther den sites (Fig. 4.1). Areas of increasingly larger size contained
proportionally less forest cover than the next smallest area (Table 4.4). Although
habitat characteristics around den sites varied among individual panthers, only 6
percent (n=2) exhibited more percent forest in the 500 m circle than in the 100 m
circle. In no instance did 1000 m or 5000 m circles contain proportionally more
forest than 100 m circles. No significant differences were found in the proportion
of forest cover among radial areas around male black bear dens (F=0.244, p=0.865,
df=3) and female black bear dens (F=0.351, p=0.789, df-3). Forest cover within
the 100 m radius area around individual bear dens ranged from 13.5 percent to 100
percent, and no trend in coverage was apparent in comparisons with larger areas.
Clearly, selection of natal and winter den sites is influenced not only by
available habitat but also by species, sex, and individual preferences. Interestingly,
only one panther (female #11, 1986, 1988) and one bear (female F03, 1993, 1995)
were known to reuse a den location. Even though it was not possible, within the
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
confines of this study, to measure all individual tendencies, a decrease in forest
cover with increasing distance from the den was consistent among panthers.
While male panthers have regularly used the entirety of the known South Florida
panther range (Machr et al. 1991a, 1992), no reproducing females have been
documented in the area's northern reaches. This begs the question of whether the
reduced amount of forest cover in areas such as Central Hendry County provides
female panthers with conditions conducive to den selection and kitten rearing.
Black bears appear much more general in their den requirements, because no
single cover type is clearly preferred (Table 4.5), and the amount of forest cover
with increasing distance from den sites does not change. A slight increase in the
amount of forest cover in the 500 m and 1000 m areas around male and female
dens suggests black bears may be more tolerant of forest edges for den sites than
panthers are. Further, denning male black bears seem to tolerate areas with less
forest cover than denning females. Some areas black bears used were fragmented
by natural influences such as tidal flowways through mangroves, or they were
artificially altered by agriculture. As noted in the food habits chapter, many black
bear foods, such as colonial ants (Crematogaster pilosa), and emergent plants,
such as alligator flag, are typical in open, unforested settings, and energetic
advantages may exist when such feeding areas are adjacent to dens. When bear
families emerge from their dens or males make periodic winter forays to obtain
food, shorter travel would help conserve and replenish stored energy reserves.
South Florida simply does not offer uniform forest conditions to panthers.
When female panther dens from eastern Big Cypress National Preserve and
Everglades National Park (n=3) are included with all South Florida dens
documented between 1986 and 1995, the importance of uninterrupted forest cover
is compelling. Of 33 known successful dens, 91 percent occurred in a continuous
band of forest contained within three public preserves (only one is managed for
panthers), an Indian reservation, and an array of bordering private lands. It is also
of interest that although the majority of successful dens were associated with this
narrow band of forest, their locations do not exhibit a tendency to be centrally
located within it Indeed, many appear to occur near the edges of this landscape
feature. Dens located near forest edges may provide females with better hunting
conditions than may be available within the center of the habitat core, especially
when their home ranges are greatly reduced while raising young kittens (Maehr et
al. 1989a). Regardless, large, uninterrupted expanses of forest are implicated in
consistent panther reproduction.
Female #14 resided in Everglades National Park and may provide some
additional insight into the value of forest to panthers. Her successful 1989 den was
typical of most panthers when examined within the confines of the 100 m radius
circle surrounding it (i.e., 100% forest cover). However, forest cover dropped from
4.2 percent to less than 3 percent in the 500 m to 5000 m radii. Apparently,
relatively small patches of forest can facilitate successful reproduction, but when
the surrounding landscape is dominated by herbaceous vegetation, the persistence
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
of the local population remains doubtful even when kittens are successfully raised.
Bass and Maehr (1991) observed that insufficient forest cover may have
contributed to the most recent extinction of panthers in the Everglades. Further,
the two successful dens in eastern Big Cypress Swamp (which also occurred in an
area of sparse forest cover and natural fragmentation) have not contributed any
individuals to the core reproducing population of residents to the north and west
During the last 10 years the southeastern Florida landscape, which includes over
795,000 ha of public lands, has produced only three documented den sites versus
31 known dens in the more densely forested area of Southwest Florida. The latter
area is also characterized by many property owners and is only 20 percent as large.
This contrast reinforces the suggestion that the majority of the Big Cypress Swamp
and the Everglades are panther population sinks that may occasionally
accommodate overflow from the better habitat and population core but do not in
themselves contribute to the growth or stability of the overall population. Perhaps
this is due in part to the lack of sufficient den habitat
Figure 2 in Maehr and Cox (1995:1014) suggests that little panther habitat
exists in Monroe and Dade counties south of the population core. To the north,
agricultural activities and the dredged Caloosahatchee River artificially separate
the core from the next largest concentration of continuous forest cover in Charlotte,
Glades, and Highlands counties where owners of private ranches are reluctant to
permit government-sponsored research. Nonetheless, panthers have been
documented here during the last three decades, and examination of Landsat
imagery suggests that this disjunct region of South Florida is probably more
capable of supporting reproduction than the habitat in most of the Big Cypress
National Preserve and all of Everglades National Park. In this peripheral area of
panther range, although forest cover is unnaturally fragmented, it is more
continuous than that found naturally in southeastern Florida.
Black bears are similar to panthers in exhibiting an aversion to the eastern
Big Cypress Swamp and Everglades National Park, even though food availability
during fall may temporarily increase bear populations in these areas. Nonetheless,
black bears seem less constrained by anthropogenic changes to the landscape and
will use dens within areas of sparser forest cover than will panthers. The ability to
negotiate obstacles such as the Caloosahatchee River has also been demonstrated
by black bears (Maehr et al. 1988) but not by panthers. Further, the effective
occupiable area for black bears is larger than that of panthers, because bears use
mangroves, and because they successfully give birth to and raise cubs in suburban
areas, such as the northern Golden Gate Estates where female winter dens have
been located within 1 km of human residences.
The natural reestablishment of a panther population in Southcentral Florida
(north of the Caloosahatchee River) appears to be hindered by formidable
landscape obstacles such as channelized rivers and lack of connecting forests. The
relocation of subadult females directly from the South Florida population into this
area may be the most practical way to determine the ability of this landscape to
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
support panthers and to reestablish a resident population. More widespread forest
in this area (Maehr and Cox 1995) relative to the Everglades suggests that
panthers may have a greater likelihood of persisting if reestablishment can occur.
Ironically, the only significant parcel of public-owned land in this three-county
area is the 25,293 ha Cecil Webb Wildlife Management Area, which is managed
primarily for northern bobwhite (Colinus virginianus) hunting. Frequent
prescribed fires and mechanical disturbances that are designed to arrest vegetative
succession and maintain an open forest canopy with light ground cover create
conditions that are not conducive to panther occupation. In fact, the GIS analysis
by Cox et al. (1994:67) revealed that this area is an inhospitable zone within a
larger matrix of potential panther habitat Thus the intensive quail management
practices employed on this tract of public land may have reduced its value to
panthers. Further, the reduction in density and distribution of saw palmetto has
eliminated both denning and feeding habitat for black bears. Although the Cecil
Webb Wildlife Management Area may not provide attractive conditions to
Florida's native large carnivores today, it certainly could be restored as valuable
denning and feeding habitat for both bears and panthers if current management
practices changed from the artificial inhibition of succession to the encouragement
of heavier patches of forest
Influence of Roads
Although Maehr and Cox (1995) found a relation between landscape island
size and panther distribution, even the largest landscape patches, as defined by the
lack of paved highways, were virtually devoid of panthers. When habitat features
are examined, however, it becomes clear that the largest roadless areas in South
Florida are dominated by herbaceous wetlands, such as sawgrass marsh, cypress
savannas, and other unforested expanses. Thus, highways have little if any
influence on panther use of these island fragments. Maehr et al. (1991a) observed
that resident adult females avoided use of areas with paved highways, so it seemed
reasonable that this influence also might extend to the selection of den sites. Little
is known about the influence of roads on Florida black bear behavior, but Beringer
et al. (1990) found that interstate highways in North Carolina were crossed with
lower frequency by bears than were smaller highways with less traffic.
Distances from dens to highways were calculated for 30 panther den sites, 25
black bear winter dens, and a randomly selected point from each animal's home
range during the year that denning occurred. Analysis of variance between known
dens and randomly selected points revealed no significant differences for panthers
(F=0.016, p=0.90) or bears (F=0.086, p=0.77 for 16 female dens, F=1.857, p=0.19
for 9 male dens). However, despite similar means (4.1 vs. 4.2 km), panther den
locations exhibited a much lower variance than randomly selected locations.
Further, 100 percent of panther dens were located >1.0 km away from roads (range
1.0 to 11.2 kin, sd=4.20), while 10 percent of the random locations were <1.0 km
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
away (range 0.1-0.7). This suggests that resident female panthers tolerate some
proximity to roads when not tending dependent kittens at the den, and that
locations >1.0 km away from roads are chosen for den sites.
Black bear natal dens were found closer to highways than were panther dens
(F=8.32, p=0.006). These distances ranged from 0.06 to 6.39 km (sd=2.02) and
likely result from the black bear's tolerance to a wide variety of den situations. It
also may be a result of smaller home range size and trap site selection. Because
most trap sites were accessible by vehicle and, therefore, close to roads, and
because black bear home ranges are considerably smaller than panther home
ranges (see home range and land tenure chapter), it is likely that females
inhabiting interior forests such as the Fakahatchee Strand were not well
represented in this sample. Thus, these data should not be interpreted to suggest
that female black bears prefer den sites close to roads, but rather, that some bears
are more likely to inhabit and den in areas that are closer to roads than are
panthers. Most certainly, there are many South Florida black bears that routinely
den as far away from roads as female panthers, but these individuals may not have
been equally susceptible to capture.
These analyses indicate that black bears utilize more habitats for dens and
tolerate more anthropogenic disturbances than do female panthers. Further, black
bear numbers in South Florida should be expected to be much higher than
panthers, not only because black bears have smaller home ranges, but because they
seem more tolerant of highways than are panthers. Areas that panthers use only
occasionally can also be readily used by female black bears that contribute to
reproduction. This same zone, which appears to be a 2-km-wide band around
paved highways, may reduce the potential population size of panthers in South
Florida.
Table 4.1. Contingency tables of percent frequency of habitat types surrounding Florida panther natal dens within a 100 m radius and a 1
km radius. Numbers in parentheses represent habitat composition within I km radius of den site. Probabilities in bold face are not
significant (p>0.05)
(P.
TS
--
Cat No.
09
09
09
11
11
11
11
11
14
19
19
19
19
19
31
31
Habitat type'
Year PP HH FM CS MS AD BA
1987 2.7 0(0.9) 0(1.2) 97.3 0 0 0(0.1)
(20.5) (77.3) 0 (0.04)
1988 0 2.7 0 0 97.3 0 0
0 (29.4) 0 (0.98) (69.6) 0 0
1990 0 10.8 0 0 89.2 0 0
0 (35.9) (14.3) (23.3) (27.4) 0 0
1986 0 32.4 2.7 0 64.9 0 0
(0.4) (37.3) (42.1) (2.6) (17.2) (0.1) (0.1)
1988 0 32.4 2.7 0 64.9 0 0
(0.4) (37.3) (42.1) (2.6) (17.2) (0.1) (0.1)
1990 0 56.8 0 16.2 27.0 0 0
(1.2) (34.1) (23.4) (4.6) (30.6) (4.3) (1.9)
1991 13.5 10.8 0 5.4 62.2 5.4 2.7
(33.5) (15.7) (5.1) (12.1) (4.8) (26.2) (1.5)
1993 0 48.6 16.2 0 35.1 0 0
(1.0) (38.9) (43.3) (1.9) (14.4) (0.2) (0.1)
1989 0 8.1 91.9 0 0 0 0
0 (2.4) (95.8) 0 0 0 0
1988 8.1 32.4 2.7 54.0 0 2.7 0
(20.5) (16.6) (7.7) (17.6) (5.5) (21.0) (2.1)
1989 0 70.3 0 29.7 0 0 0
(0.4) (59.6) (2.3) (12.8) (24.3) (0.4) (0.2)
1990 10.8 10.8 0 78.4 0 0 0
(16.1) (8.6) (1.5) (35.6) (0.1) (24.7) (13.3)
1992 2.7 35.1 0 62.2 0 0 0
(3.7) (5.6) (15.4) (75.2) 0 0 0
1994 8.1 48.6 2.7 16.2 24.3 0 0
(14.1) (45.8) (2.8) (19.3) (15.4) (0.6) (0.9)
1989 13.5 0 0 51.3 0 0 35.1
(15.4) 0 0 (43.6) 0 (28.0) (11.8)
1990 0 0 0 100.0 0 0 0
(11.1) (5.3) (4.2) (58.0) 0 (14.6) (6.5)
WA
0
0
0
0
0
0
0
0
0
0
0
0
0
(0.6)
0
0
0
0
0
0
0
0
0
0
0
0
0
(1.1)
0
(0.04)
0
(0.1)
e p
18.17 0.006
27.84 <001
82.87 <.001
65.98 <.001
65.98 <001
43.12 <.001
80.78 <.001
25.43 <.001
4.93 0.085
62.07 <.001
35.21 <001
56.98 <001
38.31 <001
6.505 0.482
40.45 <.001
53.13 <.001
Table 4.1 (continued).
Cat No. Year PP HH FM CS MS AD BA
31 1991 18.9 35.1 0 37.8 5.4 2.7 0
(15.1) (15.0) (6.9) (13.2) (5.1) (30.0) (4.4)
32 1989 43.2 0 0 56.8 0 0 0
(35.6) (0.04) (1.5) (40.0) 0 (14.0) (8.1)
32 1992 27.0 2.7 0 70.3 0 0 0
(24.2) (14.5) (5.9) (52.9) (1.1) 0 (13)
36 1990 40.5 18.9 0 24.3 16.2 0 0
(33.8) (9.1) (6.4) (45.5) (4.2) (0.8) (9.3)
36 1991 89.2 2.7 0 0 5.4 2.7 0
(20.0) (4.1) (0.9) (34.5) (23.7) (7.4) (93)
36 1993 0 0 0 32.4 67.6 0 0
(0.1) (8.9) (5.0) (573) (13.9) (14.2) (0.6)
40 1990 5.4 0 8.1 86.5 0 0 0
(14.8) (2.3) (12.9) (69.6) (0.4) 0 0
40 1992 37.8 2.7 16.2 43.2 0 0 0
(29.1) (1.0) (23.9) (45.9) 0 (0.1) (0.04)
40 1993 37.8 2.7 8.1 513 0 0 0
(21.6) (2.2) (12.8) (61.0) (0.3) (0.8) (13)
48 1993 10.8 21.6 29.7 37.8 0 0 0
(7.0) (13.5) (25.6) (34.1) (2.3) (13.3) (1.6)
48 1995 32.4 0 32.4 35.1 0 0 0
(15.2) (33) (17.7) (27.8) (1.7) (25.0) (8.4)
52 1993 0 81.1 0 0 0 0 0
(1.2) (19.4) (11.9) (3.1) 0 (27.0) (1.7)
52 1994 0 100 0 0 0 0 0
(0.2) (46.8) (4.1) (11.1) 0 (0.3) (0.1)
56 1994 54.0 0 8.1 37.8 0 0 0
(30.5) (0.9) (20.7) (45.9) (0.1) (1.0) (0.9)
56 1995 0 0 0 973 0 2.7 0
0 (29.4) (2.1) (38.1) (4.7) (25.5) (0.2)
Means 14.7 21.5 7.1 36.2 18.0 0.5 1.2
(12.5) (17.5) (14.8) (31.2) (9.2) (9.0) (2.8)
'Abkwviation. stand for the f&aoi bittyp PP- pine Stwoods, HWH- bdwood hm F- i fr mrsh & w pim, C9 cs sw MS-
swmp, AD- qsicu~ mpov;d pIhme & &ditrd, BA- buln WA- open water, TDc swmp.
A
WA
0
(9.5)
0
0
0
0
0
0
0
0
0
0
0
0
0
(0.04)
0
0
0
0
0
(0.2)
0
(0.04)
0
0
0
0
0
0
0
(0.4)
TS
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
18.9
(35.4)
0
(37.3)
0
0
0
0
0.6
(2.3)
. p
64.05 <001
27.25 <001
19.07 .0019
24.89 .0003
102.49 <001
70.96 <001
10.02 .0401
3.641 .7251
8.75 .1878
23.09 .0016
50.00 <001
87.76 <.001
72.44 <001
15.73 .0153
80.64 <001
16.15 .0402
Table 4.2. Contingency tables ofpercent frequency of habitat types within 100 m and 1 km radii of female b bc bear wint dens.
Numbers in parentheses represent habitat composition within I km radius of den. Probabilities in bold face are not significant (p>0.051
MG WA AD BA A p
0 0 0 0 24.0 .0004
~
IID Year
F02 1992
F03 1993
F04 1992
F04 1993
F06 1993
F08 1992
F08 1993
F09 1992
F09 1994
F10 1994
F11 1993
F12 1993
F13 1993
F15 1993
F17 1994
F19 1994
Means
PP IH MA CS MS TS
0 54.0 29.7 0 16.2 0
(0) (27.0) (52.7) (2.6) (12.3) (0)
0 48.6 0 0 32.4 0
(0) (37.9) (0) (0) (60.5) (0)
0 56.8 0 35.1 8.1 0
(0.2) (67.0) (2.3) (15.5) (14.7) (0)
0 78.4 0 5.4 16.2 0
(0.4) (64.7) (3.1) (15.2) (13.7) (0)
24.3 2.7 0 51.3 0 0
(25.6) (1.9) (0) (59.2) (0) (0)
0 0 0 100 0 0
(9.0) (5.9) (0.4) (72.9) (0) (0)
0 0 0 100 0 0
(7.6) (4.6) (0) (583) (22.3) (0)
0 0 16.2 0 0 0
(0) (1.7) (41.8) (0) (0) (0)
0 0 67.6 0 0 0
(0) (0.1) (36.4) (0) (0) (0)
2.7 89.2 5.4 0 0 0
(1.3) (31.9) (30.0) (7.2) (28.8) (0)
0 5.4 35.1 59.5 0 0
(3.3) (10.8) (12.0) (73.1) (0.6) (0)
0 21.6 0 0 78.4 0
(0) (16.9) (0) (0) (53.6) (0)
40.5 10.8 0 35.1 0 0
(25.6) (7.6) (0) (50.3) (0) (0)
0 54.0 29.7 0 16.2 0
(0) (27.0) (52.7) (2.6) (12.3) (0)
13.5 0 0 37.8 0 0
(19.5) (1.3) (0) (54.5) (0) (0)
24.3 8.1 5.4 27.0 0 0
(10.7) (3.9) (2.5) (66.3) (4.6) (0)
6.6 26.8 11.8 28.2 10.5 0
(6.4) (19.4) (14.6) (29.) (14.0) (0)
PP-pme atwood. HH-hardwood hmiuodk MA-taesom maiMh, CS-wypms swamp MS-mid sw.mp, Th-hickt swmp, M(O-mInge swnp, WA-open watr,
AD-Wkarn VditubedL BA-braeL
Habitat tye'
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
0
(0)
83.8
(49.6)
32.4
(62.7)
0
(0)
0
(0)
0
(29.3)
0
(0)
0
(0)
0
(0)
0
(0)
7.3
(8.8)
(0.4) (2.3) (2.8)
0 0 18.9 24.4 .0004
(0) (0) 1.6
0 0 0 13.1 0.159
(0) (0.2) (0)
0 0 0 11.5 0.244
(0) (0) (1.8)
0 13.5 8.1 6.9 0.644
(0) (3.4) (9.8)
0 0 0 31.4 <001
(0) (4.7) (7.2)
0 0 0 49.8 <.001
(0) (0) (4.3)
0 0 0 28.6 0.001
(1.7) (0.1) (5.0)
0 0 0 19.9 .018
(0.8) (0) (0)
0 0 2.7 81.7 <001
(0) (0) (0.8)
0 0 0 18.6 0.029
(0) (0) (0.1)
0 0 0 34.6 <.001
(0) (0) (0.1)
0 0 10.8 6.86 0.652
(0) (0) (13.2)
0 0 0 24.0 0.004
(0.4) (2.3) (2.8)
0 0 48.6 26.1 0.002
(0) (6.6) (18.0)
0 0 29.7 41.3 <001
(0) (0) (8.1)
0 0.8 7.4
(0.2) (1.2) (4.7)
Table 4.3. Contingencytables of pcet frequency ofbabitat types urmunding male black ber winner dns within a 100 radius and a
1 kmradius Numbers in parenthe represent habitat composition within 1 km radius ofden. Probabilities in bold face are not
significant f(P .05).
Habitat type'
PP HH MA CS MS TS
10.8 2.7 32.4 29.7 0 0
(5.5) (8.1) (12.7) (72.1) (0) (0)
0 24.3 0 70.3 5.4 0
(6.8) (9.7) (5.2) (78.1) (0.1) (0)
43.2 0 0 56.8 0 0
(19.1) (2.8) (0) (65.7) (0) (0)
13.5 0 0 0 0 0
(57.8) (0.8) (9.9) (0.6) (0) (0)
0 48.6 51.3 0 0 0
(13.5) (0.6) (35.0) (0) (0) (2.0)
13.5 0 0 18.9 0 0
(17.4) (1.4) (1.0) (26.0) (0) (0)
0 0 513 48.6 0 0
(7.1) (9.0) (33.6) (46.1) (1.8) (0)
10.8 2.7 0 62.2 0 0
(10.6) (3.5) (0.1) (69.2) (11.1) (0)
11.5 9.8 16.9 35.8 0.7 0
(17.2) (4.51 (12.21 (44.7 (1.61 (0.21
MG WA AD BA Ae p
0 0 0 0 38.6 <001
(0) (0.2) (0) (0.2)
0 0 0 0 23.9 0.004
(0) (0) (0) (0.1)
0 0 0 0 25.2 0.003
(0) (0) (2.7) (9.7)
0 0 86.5 0 91.8 <001
(0) (0.1) 17.8 (7.7)
0 0 0 0 114 <001
(24.2) (4.5) (5.7) (14.5)
0 0 43.2 243 6.6 0.675
(0) (0) 39.7 (14.5)
0 0 0 0 24.1 0.004
(0) (0) (1.2) (1.2)
0 0 5.4 18.9 24.8 0.003
(0) (0) (2.9) (2.6)
0 0 16.9 5.4
(3.0 (0.61 (8.71 (6.31
ID# Year
M08 1992
M08 1993
M11 1992
M13 1992
M13 1993
M14 1992
M20 1993
M33 1993
Means
'PP-p. flawoo. HH-h.dwod bhammock MA-morota minmto C&-yp swamp. MS-exeddswueqi.That sqip, MG qw- swunp6 WA-opine water.
ADvqdakWmaVWAdb4 ed-m.B .
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Table 4.4. Proportion of forested cover within circular areas around Florida panther natal den sites, 1986-
1995. Means followed by different letters are significantly different (Duncan's multiple range test, p=.05).
Circle radius Area (km) Proportion forested
100m 0.03 94.1 A
500m 0.78 83.9 B
1000m 2.35 75.7 C
5000m 75.21 68.5 D
Table 4.5. Frequency of occurrence of known primary cover type at Florida panther natal dens, and winter
dens of female and male black bears in South Florida, 1986-1994.
Habitat tp
Den t .... PP HH CS MS TS MG .... AD
Panther 18 5 1 3
Fbear 5 2 7 2
Mbear 1 -4 1 1 1
IPP=pine flatwoods. HH=hardwood hammock, CS=cypress swamp, MS=mixed swamp, TS=thicket swamp,
MG=mangrove swamp, AD=agricultural/disturbed.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
LL
k'
I:r
Figure 4.1. Change in percent fret cover with increasing radial distance away from panther natal den,
black bear natal dens, and male black bear winter dens in South Florida.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
5. HOME RANGE, ACTIVITY, AND LAND TENURE
Most terrestrial carnivores maintain a familiar area throughout the year
(Ewer 1968). Maehr et al. (1991a) demonstrated resident adult Florida panthers fit
this stereotype by occupying the same area regardless of season. In some western
locations, however, cougars exhibit distinct seasonal home range shifts that
coincide with snowfall and movements of prey (Seidensticker et al. 1973; Ashman
et al. 1983; Logan and Irwin 1985). Similarly, bobcats demonstrate flexibility in
home range utilization. Some populations respond to marked changes in resource
availability (Rolley and Warde 1985; Toweill and Anthony 1988; Knick 1990;
Koehler and Hornocker 1991) while others exhibit no seasonal shifts (Buie et al.
1979; Wassmer et al. 1988). In general, populations of bobcats and cougars that
exist at higher latitudes demonstrate more distinct seasonal changes in home range
than populations at lower latitudes.
Black bears, regardless of their geographic location, often shift home ranges
in response to changing food supplies (Lindzey and Meslow 1977a; Landers et al.
1979; Garshelis and Pelton 1981; Villarrubia 1982; Klenner 1987; Doan-Crider
1995). Some of these shifts can be extensive. Rogers (1987a) recorded a non-
dispersal fall movement >200 km for a male in Minnesota. In addition,
reproductive physiology in female black bears requires denning inactivity that can
last several months (Jonkel and Cowan 1971; Lindzey and Meslow 1976a; Fuller
and Keith 1980; LeCount 1983; Rogers 1987a; Hellgren and Vaughan 1989), and
hibernation is a prerequisite for overwintering survival in most populations.
Individuals living in Minnesota have remained in hibernation for up to seven
months (Rogers 1987a). On the other hand, some black bears in the southeastern
United States remain active throughout the winter (Hamilton and Marchinton
1980; Hellgren and Vaughan 1989). Rogers (1987a) has suggested that
hibernation in black bears is an adaptation to an absence of food and is not a
behavioral mechanism to avoid cold temperatures. Given the year-round food
availability, one would expect bear-denning to be absent in South Florida. Latitude
appears to be correlated with length of the denning period (Johnson and Pelton
1980; Hellgren and Vaughan 1989). Accordingly, individuals in the southern
United States den for shorter periods, but a pulse of denning and winter parturition
is universal among black bear populations regardless of latitude.
Most solitary mammalian carnivores follow a spatial arrangement known as
land tenure, where residents have prior rights to their home ranges (Seidensticker
et al. 1973). Maehr et al. (1991a), and Maehr and Caddick (1995) suggested that
Florida panthers maintain social and reproductive stability by living in a land
tenure system. Such a system has resulted in low resident adult turnover and
limited dispersal success among panthers, especially males. Little work has
examined land tenure in black bears. However, Rogers (1987a) found that adult
females facilitated female-offspring home range establishment by shifting their
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
home ranges to accommodate daughters. In addition, he found that resident adults
reduced immigration opportunities for dispersing bears, especially males. These
patterns are similar to land tenure in Puma concolor.
Bobcats exhibit great variability in spatial arrangement from high degrees of
home range overlap between sexes, to gender segregation (McCord and Cardoza
1982; Anderson 1987). The highest densities occurred where bobcats maintained
exclusive home ranges (Lembeck and Gould 1979; Miller and Speake 1979).
Zezulak and Schwab (1979) suggested that intrinsic behavioral mechanisms
similar to those of other felid species operated also in bobcats. Bailey (1974)
introduced the concept of land tenure in this species based on his study of Idaho
bobcats. However, the variation in social strategies documented in the other
studies cited above complicates the creation of an overarching concept of bobcat
social ecology. In Florida, Wassmer et al. (1988) found that female bobcat home
ranges did not overlap and that these were generally encompassed by larger male
home ranges. Foster (1992) observed a similar pattern in Southwest Florida with
little overlap within sexes but occasional overlap between males and females.
Methods
I examined home range patterns among bobcats, black bears, and panthers in
South Florida in order to determine the influence of season on the spatial
arrangement of these species relative to each other and to conspecifics. Although
seasonal variation in panther habitat use and diet has not been observed (Maehr et
al. 1990a; Maehr et al. 1991a), and bobcats appear to exhibit consistent annual
movement patterns (Wassmer et al. 1988), bobcat diet varies seasonally in Florida
(Maehr and Brady 1986). The basis for comparisons was the distinct seasonal
patterns in black bear diet (see dietary overlap chapter), where January-April was
winter, May-August was summer, and September-December was fall. In addition,
few studies have described the fates of long-standing resident carnivores, so I also
examined the home range dynamics of individual Florida panthers relative to age
of the resident and the status of same-sex neighbors in order to better understand
the process of home range replacement
Seasonal home ranges of adult resident bobcats, black bears, and Florida
panthers were estimated using minimum convex polygons (Mohr 1947). Annual
home ranges also were determined in order to make comparisons with other studies
and to portray overlap with conspecifics and with other species. Resident black
bears were at least three years of age or exhibited reproductive activity. Bobcats
were considered residents if their movements exhibited a central tendency (Bailey
1972) and if their body mass exceeded 9 kg (Crowe 1975). Maehr et al.(1991a)
classified Florida panthers as residents if"males were greater than three years old,
exhibited regular movement patterns over large home ranges, and overlapped with
several adult females. Resident adult females were >18 months old, had small
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
home ranges, overlapped with other adult females, and exhibited reproductive
behavior (mating, denning, kitten-rearing)."
Analysis of variance was used to examine seasonal means of home range size
among species/gender groups. If a significant difference (p<0.05) among
species/gender groups was found within a season, Duncan's multiple range test
was used to differentiate means. Winter home range sizes of denning and non-
denning black bears were compared using Student's t-test (p=0.05). Individual
home range dynamics for adult panthers monitored greater than three years were
examined by calculating annual home ranges, and arithmetic home range centers
of these home ranges. Home ranges were considered stable if arithmetic means
displayed a subjectively determined central tendency. Abandonment occurred if a
subsequent home range did not overlap with the home range from a previous year.
A shift occurred if a subsequent home range center was at least one home range
radius from the previous home range center.
Black bear activity was monitored with an automatic field data recording
station. Pulse rate changes of motion-sensitive transmitters attached to black bears
were recorded with a digitized data processor, receiver (TDP-2, TR-2; Telonics,
Inc., Mesa AZ), and chart recorder (Mod. 2W288, Gulton Co., Manchester NH).
Stations were established within 100 m of dens or as close to active bears as
possible without influencing their behavior. Radio transmitters (Mods. 315, 500,
505, Telonics, Inc.) were equipped with motion-sensitive switches and variable
pulse rates: about 70 pulses per minute head up, and about 60 pulses per minute
head down. Activity rate was defined as the percentage of minutes within each
hour containing a pulse rate change (Maehr et al. 1990b).
Results and Discussion
Between January 1986 and December 1994, 8 adult bobcats (4 females, 4
males), 25 adult panthers (13 females, 12 males), and 30 adult black bears (14
females, 16 males) were monitored with radio-collars in Southwest Florida (Table
5.1). All bobcats were captured as adults, whereas one female black bear, three
female panthers, and four male panthers, were captured as dependent juveniles or
as independent subadults before they were monitored as adults. Ten Florida
panthers were monitored for at least three years (seven females, three males), and
three of these (one male and two females) were monitored for at least eight years.
Annual Comparisons
Home ranges averaged 201.5 km2 for resident adult female panthers (n=13,
range 81.1-501.8 km2, sd=101.9), 431.8 km2 for resident adult male panthers
(n=12, range =208.2-752.3 km2, sd=211.3), 54.2 km2 for resident adult female
black bears (n=14, range 10.6-205.6 km2, sd=52.4), 283.7 km2 for resident adult
male black bears (n=15, range 125.5-647.7 km2, sd=159.8), 14.0 km2 for resident
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
adult female bobcats (n=4, range 7.0-18.9 km2, sd=5.3), and 37.5 km2 for resident
adult male bobcats (n=4, range 16.6-66.9 km2, sd=24.6). Panther home range
sizes were comparable to figures reported by Maehr et al. (1991a) for the same
area, black bear home ranges were larger than those reported for Central Florida
(Wooding and Hardisky 1988), and bobcat home ranges were nearly identical to
those reported for Southcentral Florida (Wassmer et al. 1988). Measurements of
home range size fell within the extremes reported for all three species (Anderson
1983; Hopkins 1989; Wassmer 1988; Carlock et al. 1983; Beck 1991). Statistical
comparisons indicated significant differences (F=13.1, p<0.0001, df=5) among
annual home range sizes within species/gender groups. However, because black
bears exhibit such variable food habits and the diet changes seasonally, this
comparison may be misleading if Florida black bears follow the stereotypical
pattern of adjusting their movements and home range sizes relative to food
availability and denning.
Seasonal Effects
Seasonal comparisons showed that significant differences in home range size
among species/gender groups also existed (F=46.2, df=17, p<0.0001). According
to this analysis, however, male and female black bears were the only groups that
exhibited significant seasonal changes in home range size (Table 5.2). Black bears
of both sexes had the smallest home range sizes during winter when some
individuals were in maternal dens or in solitary winter dens. Winter ranges were
not significantly different from summer ranges, however, because many bears
remained active during winter (Table 5.3). Female bears that established natal
dens had smaller winter ranges (1.3 km2, n=8, sd=1.9) than those females that
remained active during the winter (13.2 km2, n=12, sd=8.0) (t=4.1, df=18,
p=0.0003) (Table 5.4). Some males also established dens, but most remained
active throughout the winter despite utilizing a much reduced area. The mean
winter home range size for males that denned was 46.6 km2 (n=5, sd=30.6),
whereas a random sample of males that remained active throughout the winter had
a mean home range size of 59.2 km2 (n=10, sd=50.2); this difference was not
significant (-=0.51, p=0.62, df=13). Although males such as M08 built elaborate
ground nests out of matted saw grass and swamp ferns or, like M20, inhabited
small areas within isolated saw palmetto thickets, movement data as well as signs
of feeding on herbaceous matter and fresh feces at the edges of these dens indicated
that denning males occasionally left their winter refugia to feed. If the foods
available to black bears during winter were of sufficient quality to maintain body
mass, as was indicated for several South Florida plant species (see dietary overlap
chapter), this would help to explain winter activity and the more rapid growth rates
versus black bears in more northern latitudes or in colder climates (Maehr et al. in
press). What is inexplicable is the absence of movements among denning females
despite warm temperatures and the availability of foods, some of which are highly
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
digestible (palm heart fibers) and high in fat content (Brazilian pepper seeds).
Apparently, the evolutionary roots of the black bear's reproductive cycle that may
date to a cold Pleistocene climate are sufficiently strong to have prevented winter
activity among denning females, even though an energetic advantage may be
obtained from occasional winter feeding. Nonetheless, home range shifts caused
by food availability changes, reproductive behavior, and possibly hibernation,
suggested that season must be taken into account when comparing home ranges of
sympatric carnivores in South Florida.
Male panthers exhibited larger home ranges in every season than any other
species/gender groups (Table 5.2). During winter, female panthers had larger
home ranges than black bears and bobcats, which were not significantly different
from each other. In summer, home ranges of female panthers, male black bears,
and male bobcats were not distinguishable from each other, but female panther and
male black bear home ranges were larger than home ranges of female black bears
and female bobcats. The home range sizes of the latter two species/gender groups
were indistinguishable from those of male bobcats. During fall, male black bear
home ranges were larger than those of female black bears and bobcats but were not
distinguishable from female panther home range sizes. In general, home range
dynamics in black bears explain the complicated pattern of seasonal variation in
home range size differences among all three large South Florida carnivores.
Home range size relationships remained constant between male and female
panthers, likely due to prey distributions that did not change seasonally (Land et al.
1993) and due to the nearly continuous constraints placed on female panther
movements by their kittens (Maehr et al. 1989a, 1991a). Maehr et al. (1991a)
found that non-reproductive but otherwise healthy adult female panther #18
exhibited a home range that was comparable in size to some resident males. In
contrast, although bobcats did not exhibit significant seasonal changes in home
range size, there were no gender-related differences in home range size during any
season (Table 5.2). Anderson (1987) indicated that bobcats exhibit pronounced
sexual dimorphism; however, bobcat mass measurements in this study (Table 5.1)
suggested that such differences were slight Mass measurements in Foster (1992)
indicate that males were 27 percent larger than females in the same study area
(t=9.5, p<0.0001, df=16), a difference which is at the low end of the spectrum for
sex-related mass differences in this species. Relatively similar body sizes may help
explain similar patterns in use of the landscape, particularly those resulting in use
of similar habitat and prey resources by male and female bobcats. It is interesting
that the only season in which male bobcat home range size approached
significance over smaller female means was during summer (Table 5.2). This
season overlaps with periods of female fertility in other areas (Crowe 1975; Mehrer
1975), thus larger home ranges may have resulted from increased movements of
males in search of mates. Unfortunately, there is insufficient information on
bobcat reproductive characteristics (Anderson 1987), and even less on bobcat
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
reproduction in Florida, to rule out any other factors that may explain this pattern,
such as variation in food resources.
Because of its tropical influence, low latitude, and its limited altitudinal
variation, seasonal effects such as day length and temperature are dampened or
moderated in South Florida. Further, a high level of habitat interspersion provide
year-round food resources for herbivorous prey species. Land et al. (1993) found
that white-tailed deer in Southwest Florida responded to changes in food
availability but did not exhibit disjunct use areas. The abandonment by some
western ungulates of summer ranges compels sympatric cougars to display
altitudinal home range dynamics (Rasmussen 1941; Seidensticker et al. 1973).
Florida panthers can maintain consistent use of home ranges, because prey
densities and distributions remain relatively constant throughout the year (Figs.5.1-
5.5). Some changes in the distribution of radio-location frequency within home
ranges of female panthers can be attributed to denning and kitten rearing (Machr et
al. 1989a) (Figs. 5.1,5.2). In the case of adult male #13, his southward shift and
home range contraction in 1987 (Fig. 5.4) was in response to maturing female
panther kittens and possibly, attempts to avoid the resident adult males in the area
(Maehr et al. 1989a, 1991a).
Rodents and lagomorphs maintain small areas of activity throughout the year
(Holler 1992; Chapman et al. 1982) and do not appear to shift home ranges
seasonally. Further, in Florida most bobcat prey species remain active year-round
and provide bobcats with geographically stable food supplies. Bobcats in
Southwest Florida exhibited the consistent annual home range patterns (Fig. 5.6)
predicted by a constant food supply and common to other studies of the species in
the southeast (Wassmer et al. 1988). Only during winter is there a potential for
measurable and predictable changes in food availability as avian migrants, such as
gray catbirds (Dumetella carolinensis), descend upon South Florida's forests.
Maehr and Brady (1986) measured an increase in bird consumption by Florida
bobcats that coincided with the peak in land bird abundance in this part of the state
(Robertson and Kushlan 1974). This apparent response by bobcats to an annual
increase in food supply occurs without the spatial shifts that most black bears
exhibit to fall food distribution. If bobcats alter their prey search images during
such times of superabundant avian prey, then as Maehr and Brady (1986) found,
migrants as well as resident, non-migratory breeders should be expected to increase
in bobcat diets during winter. With the return of neotropical migrants to northern
breeding grounds, the diets of South Florida bobcats return to a predominantly
rodent and lagomorph fare without causing significant effects on home range size.
Black bears in South Florida follow patterns of home range dynamics that are
generally similar to those of the species throughout its range (Figs. 5.7-5.10). For
both males and females, home range size was smallest during winter, however, the
amount of variation among individuals during this time of year made differences
between summer home range sizes insignificant (Table 5.3). Fall home ranges of
male and female black bears were significantly larger than during other seasons.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Female Black Bear Denning.- Among all sex and age classes, only
pregnant black bears consistently ceased movements during winter and denned.
Den entrance and emergence dates averaged 29 January and 18 April, respectively.
Sizes of neonates handled in dens suggested that parturition in South Florida black
bears occurs on about 1 March. Four adult females are known to have abandoned
den sites. F04 and F11 abandoned dens in open wetlands after their solitary cubs
were handled by researchers in 1992 and 1993, respectively. F07 apparently
abandoned a site located in a mangrove swamp after an unusually high tide and
unusually high rainfall inundated her den during March 1993. F17 abandoned a
natal den after the saw palmetto thicket in which it was located was burned by a
prescribed fire on the Florida Panther National Wildlife Refuge on 28 February
1994.
Solitary adult females and adult females with dependent cubs from the
previous year remained active during winter. The only exception was an adult
female with three 9-month-old cubs that was hit by a car, sustaining breaks in her
humerus and mandible on 12 December 1993. After F21 was taken 100 m from
the highway, she remained stationary for the remainder of the winter in a
hardwood hammock. The three cubs were seen periodically after the accident
feeding on live oak acorns and are presumed to have survived. F21 made small
movements (<200 m) around this site until 6 April 1994 when she resumed normal
movement patterns that were indistinguishable from other female black bears.
Comparable healing abilities were observed in an adult female black bear in Ocala
National Forest in 1985 (Maehr pers. observ.). After breaking an ulna and radius
in a snare, the adult female was recaptured 30 days later in a culvert trap with both
bones fully healed and exhibiting a weight gain of 6.8 kg. Black bears throughout
their range tolerate a wide range of limb injuries (i.e., Stone et al. 1975; Anderson
1989) that would likely be fatal to wild felids.
Male Black Bear Denning.- Some adult males maintained winter dens, but
denning bouts were occasionally interrupted by short movements away from the
den. Average den entrance and emergence dates for male black bears were 10
February and 24 March, respectively, and did not appear to be age-related (n=8,
range of 2-10 years of age). Duration of den attendance by male black bears
ranged from 13 to 50 days and averaged 33.3 days (n=9, sd=12.1). Male M33
during 1993 exhibited two denning periods between January and April 1993 that
totaled 70 days.
Expanding summer ranges of black bears coincided with increasing
temperatures, plant regrowth, and the breeding season. Encounters between adult
males and females, based on coincident radio-locations, were recorded mostly from
April through September. Other evidence of a mating season included vaginal
swelling, fresh puncture wounds, and lacerations that may have resulted from
breeding or fighting for breeding rights (Table 5.5). Coincident radio-locations
and other evidence of sexual interactions peaked between May and August. In
addition, the only family group (consisting of adult female F03 and three radio-
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
collared male cubs) monitored in this study dissolved during the month of August
(Fig. 5.11). F03 left her 17-month-old cubs in their 1992 summer range before
moving 5 km to an area of abundant oaks and saw palmettos. She subsequently
denned the following winter in a hollow cypress stump and gave birth to at least
two cubs. For most adult bears, summer ranges were usually expansions of winter
ranges with considerable overlap between the two areas (Figs. 5.7-5.10).
Florida panthers do not have a distinct breeding season, but mating activities
influence panther movements. Although panthers are physiologically capable of
reproducing throughout the year, most births follow an increased period of sexual
activity during the winter and early spring (Maehr et al. 1991a). This tendency
toward higher winter activity may explain the pattern of kitten independence
whereby 89 percent of nine documented family break-ups occurred between
November and May (Table 5.6). In several instances, an adult male was in the
company of a female panther with kittens immediately before the family bond
dissolved. The average age of kitten independence was 13.8 months (n=9,
sd=2.72) and ranged from 10 to 18 months. At least one instance of family break-
up was probably caused by the capture of male kitten #54 at 10 months of age.
Although female #40 and her kitten (#54) were not found together after the kitten's
capture in February 1993, he survived this early independence and was a resident
adult at the time of this writing. In most cases, subadults dispersed from their
mothers' ranges immediately after obtaining independence (Figs. 5.12-5.14).
However, male #30 remained in his mother's home range for at least six months
before dispersing, and kitten #54 localized his activity in the area where female
#40 abandoned him.
For black bears of both sexes, increased movements during fall resulted in
home ranges that often encompassed, the areas used during the previous two
seasons, or that were larger and disjunct from them. Telemetry locations during
these months were often near or in vegetation communities containing common
fruit-producing plants, such as saw palmetto, cabbage palm, and live oak. This
pattern of fall vagrancy has been observed in many black bear populations
(Garshelis and Pelton 1981; Villarubia 1982; Rogers 1987a), and is related to the
availability of high-energy food sources that often are clumped and disjunct from
winter and summer ranges (Eagle and Pelton 1983). Some bears, however, did not
always exhibit consistent patterns of inflated fall home ranges such as M08, and
M13 during 1992 and 1993. This may be attributable to annual variation in food
abundance despite my observation that staple foods, such as fruits of saw palmetto
and cabbage palm, may vary among individual plants but locally appear to produce
annually stable supplies. Further, neither bear inhabited an area where commercial
saw palmetto fruit-collectors decimated food supplies in order to provide the raw
material for pharmaceutical products (Maehr and Layne 1996). In South Florida,
adult black bear home ranges were not only larger during fall, but they could be
separated by more than 20 km from summer ranges. In several cases, particularly
adult male M06, the shift from a summer to fall range occurred quickly (i.e., <3
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
days). In this case, the bear left a summer range dominated by mixed swamp
vegetation in favor of pine flatwoods containing extensive thickets of saw palmetto.
Bear scats collected in this area confirmed that fruit of saw palmetto was consumed
nearly to the exclusion of other foods. The rapid movements of M06 to his disjunct
fall range suggest that he was previously familiar with this clumped food supply.
Such learning may be important to maximizing mass growth and in building fat
supplies, factors of particular importance to pregnant females that den by late
January, give birth in late winter, and emerge with cubs in mid-April following a
2-3 month fast
Home Range Fidelity and Replacement
While seasonal patterns in home range size were examined for all three
species, only panthers were monitored adequately to examine the process of
resident senescence and home range replacement Maehr et al. (1991a) observed
that through 10 years of radio tracking, the permanent abandonment of a home
range was rare. Adult female #09 left a home range in the southern Golden Gate
Estates and colonized the vacated home range created by the removal of non-
reproductive female #08 in 1987 (Fig. 5.15). Her subsequent litter consisted of two
kittens, twice the number of kittens produced by her in each of two previous litters.
Since her two male kittens were removed for captive breeding in 1991, #09
continues to occupy the same home range but has not reproduced (possibly as the
result of reproductive senescence at 10-11 years of age). Thus, like the tenure of
female #08 in the same location, successful reproduction is not a key element for
maintaining a resident home range even though the quality of that home range
may enhance the reproductive fitness of a younger female. Adult female #19 raised
her first litter in her mother's home range before dispersing and establishing a new
breeding territory adjacent to her natal range (Maehr et al. 1989b). Male panther
#26, although considered an adult when captured in 1988, was not documented as
a breeder until he filled a home range vacancy created by the death of male #17 in
1990 (Fig. 5.16). The turnover of this home range to a new resident occurred amid
a complex arrangement of subadult males and non-resident adults that lived at the
periphery of occupied panther range in eastern Collier County (Fig. 5.17). It is
possible that the failing health of male #17 was recognized by as many as four
other males and may explain the temporarily high density of males in this area
from 1991 through 1992. The pattern for most adults, however, was to maintain
home ranges with stable home range centers over many years (Figs 5.18-5.20).
Resident male home ranges appear to occupy the same space regardless of the
occupant. The shapes of such traditional home ranges are likely a function of the
distribution of dense forested cover and the distribution of females. However, adult
male #16 continued using Everglades National Park for five years after all
documented females in that subpopulation died (O.L.Bass pers. comm.), suggesting
that familiarity with a home range may encourage fidelity to it Telemetry data
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
collected from the Fakahatchee Strand exemplify the concept of the traditional
home range, because at least five adult males have occupied this distinct vegetative
system from 1981 through 1994, with little variation in the shapes and arithmetic
mean centers of their home ranges (Fig. 5.21). Whether the deaths were caused by
highway collision or intraspecific aggression, a replacement for the lost resident
appeared quickly, and no interruptions to local reproduction were observed.
Resident male #12 demonstrated site fidelity for over eight years, and
interacted with at least six adult females during this time span. His home range
boundaries expanded and contracted occasionally, but his center of activity
remained relatively stable (Fig. 5.22). Contractions coincided with the presence of
other adult males such as males #37 and #51. After #37's death from highway
collision, #12's home range expanded to recolonize the area previously ceded to
#37. The appearance of male #51 in 1992 preceded another home range
withdrawal by #12 from the southern Fakahatchee Strand. He was subsequently
killed by adult male #46 in an area that #12 had not used during eight previous
years of study. In this case, I suspect that failing health reduced the ability of #12
to adequately patrol the entirety of his long-standing home range and became
vulnerable to the aggression of competing males that he previously had
successfully repelled or killed.
Bears were insufficiently studied to allow the characterization of individual
home range dynamics over time. However, the sample of adult male black bears
was large enough for a comparable range of ages to be contrasted with male
panther #12. An examination of panther #12's annual home range sizes revealed
the fluctuations caused by neighboring individuals and the declines associated with
failing health. A comparable pattern of relatively constant home range size in
male black bears is also apparent from 4 to 11 years of age. This was followed by
older animals with larger home ranges, a distinct contrast to the pattern exhibited
by panther #12. While this comparison is confounded by the variation inherent
among individual bears and the quality of habitat within which their home ranges
are distributed, it does suggest that adult male age results in different spatial
patterns between the two species. Because panthers exhibit a life style that is
continually violent (i.e., prey procurement, territory defense), and individual fitness
is dependent upon the ability to kill large prey and defend territories from
competitors, minor injuries and senility likely have significant influences on the
ability to maintain dominance of a home range. Black bears, on the other hand, do
not require agility or strength to maintain adequate nutrition, and there was no
evidence that male black bears continually defended territories against other males
(fighting seemed to be restricted to the breeding season and may have been related
to the distribution of females, and not the territories of other males). Further,
advancing age in black bears may afford some advantage in that older individuals
may have greater experience with patterns of food distribution, and thus, may be
more efficient in their use of the landscape. The larger home range sizes of older
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
bears may simply be related to a better knowledge of alternate food sources, and
not displacement by younger males.
Overlap Within and Among Species
Patterns of home range overlap among Florida panthers were similar to the
arrangement of resident adults described by Maehr et al. (1991a) (Fig 5.23).
Indeed, 9 of the 13 residents monitored in 1991 were still occupants of the same
areas in 1993. With the exception of the southern Fakahatchee Strand and female
#09, overlap among females was high, whereas males overlapped only at the
peripheries of their home ranges. The greatest difference in panther home range
distribution between 1991 and 1993 was the colonization by female #52 of a part of
the Okaloacoochee Slough on private land where female occupation previously had
not been documented. Florida panthers clearly exhibited the characteristics of the
land tenure system that has been reported for the species throughout its range.
The study period was insufficient to determine definitive patterns in land
tenure among black bears in South Florida and examples of home range
replacement were not documented. However, resident adult females exhibited
home range fidelity from year to year, particularly during winter and summer.
Variation within females between years during fall was likely a product of the
biannual cycle of cub-rearing. Females with large fall home ranges likely were
traveling without cubs. Adult males monitored more than one year exhibited
consistent movement patterns between years, punctuated by annual fall
peregrinations. After the first full year of radio-tracking 14 adult black bears,
home range distribution and overlap suggested a landscape that supported varying
densities of adults with gaps between groups of individuals. With 15 additions to
the adult sample in 1993 (Fig. 5.24), the distribution of home ranges filled in some
of the apparent gaps observed in 1992. Distribution of collared female home
ranges was more a reflection of trap site location than demography. Smaller home
ranges made females less vulnerable to capture, because trap sites were not
concentrated enough to sample all individuals in the study area. Females probably
were as evenly distributed across the landscape as males, but wider movements
increased the likelihood that males would span the distances between trap
locations. Overlap between and within genders ranged from entire to minimal,
with as many as five individuals overlapping each other. In no case was there an
impression that all the bears between trap sites had been captured; thus population
numbers and density were probably higher than indicated by these results. Males
and females exhibited similar amounts of overlap.
Black bears routinely used woodlands close to human population centers,
such as Naples, Marco Island, and Ochopee; areas that panthers typically avoided.
Three dispersal-aged bears (M05, M07, and Mil) were captured in residential
areas within front or back yards of human dwellings in Collier County. In
addition, some black bear home ranges (i.e., F07, F09, M02, M13, and Mi8)
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
included large areas of mangrove forest, a plant community that covers over
171,000 ha in South Florida (Odum and McIvor 1990), and was a habitat type that
neither bobcats nor panthers were found to use. Although black bears and bobcats
were not concurrently monitored, home ranges of most radio-collared bobcats were
overlapped by several black bears in space if not in time. From a strictly spatial
perspective, small winter ranges and denning among many black bears reduced the
potential for interaction with South Florida's native cats. About half of all adult
females each year give birth to litters, so 50 percent of the adult female population
effectively disappears each winter. Thus, based strictly on home range size and
movement patterns, the highest likelihood for interaction between black bears and
sympatric felids is during summer and fall when black bears often move widely in
search of mates and food.
While black bears clearly utilized the same landscape as did panthers,
temporal differences in spatial arrangement between these two species accentuated
the differences caused by the distinct seasonal pulses exhibited only by bears.
Maehr et al. (1990b) found that Florida panthers, whether solitary or tending to
kittens at dens, exhibited a pattern of sinusoidal activity with crepuscular peaks.
They presumed that this pattern coincided with the well-documented activity
tendencies of potential prey. Activity patterns were not determined for bobcats;
however, black bears exhibited a contrast to panthers with higher activity rates
throughout the day with a diurnal peak at midday (Fig. 5.25). This finding
supports the idea that prey behavioral characteristics not only influence the
distribution and abundance of predators (Elton 1942; Chitty 1950; Kale 1965:58)
but the activity of predators as well (Powell 1982:123). As predators of primarily
sessile food sources, black bears do not need to adjust their activities temporally in
order to forage efficiently. Although many of the insects that bears feed on are
highly mobile as individuals, the highest concentrations of energy can be found in
eggs and larvae of termites, ants, wasps, bees and beetles. Adults of many colonial
insects are diurnally active and provide visual and chemical cues to the presence of
their nests which provide high nutritional rewards. These behavioral tendencies
may encourage diurnal activity in black bears.
Hourly measurements collected at automated data processing stations
indicated that free-ranging black bears without cubs (n=6; 175 hours) exhibited a
bimodal pattern with peaks in activity around 1100 h and 1900 h (Fig. 5.26). In
addition, denning females (n=4; 339 hours) demonstrated a nearly identical pattern
with activity peaks at 1100 h and 1800 h without leaving their dens. A single adult
male (M08) monitored for 49 consecutive hours at his 1992 winter den showed a
mid-morning activity peak with lesser increases in activity between 1400 h and
2300 h (Fig. 5.26). Comparisons of activity profiles showed that both panthers and
black bears exhibit two peaks during 24 hours; however, their peaks are out of
phase with each other. Panthers are clearly crepuscular (Maehr et al. 1990b),
while black bears are diurnal with a secondary pulse of activity at or shortly after
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
sunset Black bears exhibited reduced activity from about 2100 h through 0800 h,
the time period within which both panther activity peaks occurred.
Telemetry data and observations in the field during panther capture efforts
indicated that black bears were found throughout occupied panther range. Home
ranges of several bears were completely contained within larger panther home
ranges (Figs. 5.27, 5.28, 5.29), whereas other bears, such as those inhabiting the
Fakahatchee Strand abandoned permanently occupied panther range by traveling
east into the Deep Lake Unit of Big Cypress National Preserve to forage on saw
palmetto fruit (Fig. 30). The spatial and temporal use of similar landscapes by
black bear and panther differ so it is likely that direct encounters are minimal
unless one species routinely preys on the other. Contrasts in food habits and non-
overlapping periods of daily activity of these species in South Florida suggest this
is not the case.
The distinctly diurnal activity of South Florida black bears reflects the limited
influence of humans on their behavior and coincides with observations of an adult
female black bear in an area of relatively low human activity in northeastern
Minnesota (Rogers 1987a). Similarly, black bears inhabiting remote areas of Idaho
(Amstrup and Beecham 1976), Great Smoky Mountains National Park (Eubanks
1976), and using natural forage in Sequoia National Park (Ayres et al. 1986)
exhibited diurnal activity patterns that were comparable to those of South Florida
black bears inhabiting remote or access-limited areas such as the Fakahatchee
Strand and Florida Panther National Wildlife Refuge. Among closely related
species, Reid et al. (1991) found that Asiatic black bears in remote areas of China
were primarily diurnal as were giant pandas in similar habitats (Schaller et al.
1989).
High levels of human activity in occupied bear ranges consistently shift bear
activity toward nocturnality, and black bears that used foods of human origin near
campgrounds were relatively inactive during daylight (Ayres et al. 1986).
Individual European brown bears (Ursus arctos) in Italy (Roth 1983) and Spain
(Clevenger et al. 1990) eschewed daytime activity in areas of moderate to high
human activity, but in a remote area of Yugoslavia they exhibited diurnal activity
(Roth and Huber 1986). In North America, nocturnal activity among grizzly bears
in Yellowstone National Park was attributed to visitor recreation (Gunther 1990),
whereas brown bears in remote areas of Denali National Park were mostly diurnal
(Stelmock and Dean 1986). Although activity of South Florida black bears
inhabiting the urban-wilderness interface were not monitored in order to reveal
activity patterns unique to bears at the fringe of occupied range, most complaints
by local residents and beekeepers resulted from the nocturnal activities of
opportunistic individuals. This suggests that South Florida black bears exhibit
plasticity in temporal feeding tendencies, but where human influence is light, they
exhibit the diurnal patterns expected for most undisturbed bear populations. Thus,
the pattern in Florida appears to support the generality for the family Ursidae:
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
With adequate space and appropriate resources, bears will tolerate (and in some
cases take advantage of) anthropogenic dominance of the landscape.
Bobcats maintained relatively small home ranges that did not overlap with
other instrumented same-sex conspecifics. Sporadic trapping efforts, however,
precluded thorough sampling of even a portion of the study area, so actual densities
were likely much higher than these results indicate. The findings of Wassmer et
al. (1988) and Foster (1992) suggest that within forested landscapes, bobcat home
ranges should be continuous with some overlap among residents. If one assumes
that South Florida bobcats in 1986 and 1987 exhibited spatial patterns similar to
those in Southcentral Florida and they were similar to bobcats studied in the same
area five years later, then a single resident male panther should encompass at least
12 adult female bobcat home ranges. Overlap among bobcats and black bears
should vary with season. During 1987 alone, the home range of female panther
#11 overlapped with four radio-collared adult bobcats (Fig. 5.6). Bobcats were
similar to bears in tolerating closer proximity to human habitations than panthers.
Although none of the adults collared in this study lived adjacent to urban areas,
two dispersal-age females were captured in lightly wooded residential or industrial
areas east of Naples, Florida, and field sign encountered during 1987 indicated that
bobcats inhabited coastal habitats surrounded by urban areas such as Pelican Bay
in North Naples.
Within the forested area of Collier County (i.e., east of County Road 951,
north of U.S. Highway 41, west of State Highway 29, south of Immokalee, and
north of Interstate 75, bobcats, black bears, and Florida panthers exhibit
continuous, overlapping distributions. Outside this area black bears inhabiting
mangroves and other plant communities near the coast likely avoid potential
contact with bobcats and panthers. Other zones of allopatry may exist where
Florida panthers appear to occur at low density or are absent such as in the urban
areas of South Florida, the suburbanized Golden Gate Estates (north of Interstate
75), and most of the Big Cypress National Preserve and Everglades National Park
where forest cover is sparse and naturally fragmented (Maehr and Cox 1995).
Table 5.1. Annual home range sizes of adult black bean, bobcats, and panthers in south Florida, 1986-1994. Years in bold type indicate
denning for that individual.
Home
range Age (years) at Adult Home range size
I Sex Capture date year first capture weight (kg) Locations (k)
Bears
F02'
F03'
F04'
F05'
F07'
F08'
F09'
F10'
FIO'
F11'
F12'
F13'
F15'
F17'
F19'
M03'
M06'
MO8'
M12'
M13'
M17"'
MiS'
M20'
M24'
M25'
M28'
M29'
M36'
M39'
M41'
M42'
5/9/91
8/15/91
8/15/91
9/20/91
10/29/91
11/5/91
11/8/91
11/14/91
5/12/92
6/1/92
6/17/92
10/25/92
11/25/92
12/16/92
2/18/91
8/8/91
8/14/91
9/25/91
10/18/91
1/19/92
1/30/92
2/7/92
6/12/92
7/30/92
10/8/92
10/8/92
5/26/93
7/28/93
7/31/93
8/12/93
101
70.3
63.5
58.0
88.4
111.6
77.1
75.7
63.5
77.1
81.6
68.0
90.7
88.4
147.4
138.3
104.3
147.4
154.2
124.7
220.0
112.0
163.3
139.7
97.5
124.7
165.6
147.4
104.3
145.4
40.5
205.6
40.7
37.0
21.9
11.9
17.7
101.9
73.0
23.5
43.2
10.6
98.1
33.3
311.0
147.0
125.5
586.2
159.3
25.0
362.1
181.1
418.8
166.2
647.7
204.4
305.0
166.0
228.6
246.3
Table 5.1. (continued)
Home
range Age (yeas) t Adult Home range ize
ID# Sex Capture date year first capture weight (kg) Locations (km)
Panthers
F
F
F
F
F
F
F
F
F
F
F
F
F
M
M
M
M
M
M
M
M
M
M
M
M
3/25/84
1/26/85
1/21/86
1/22/87
2/9/87
1/12/89
2/3/89
1/27/90
2/26/90
2/28/90
2/24/92
2/25/92
5/5/92
1/28/86
2/27/86
1/20/87
3/10/87
2/16/88
3/1/88
11/29/88
1/3/89
1/8/90
1/30/90
1/30/92
3/26/92
1986
1986
1986
1987
1989
1989
1989
1990
1992
1990
1993
1992
1993
1986
1986
1987
1987
1988
1989
1991
1991
1993
1990
1993
1993
152.0
228.8
171,0
501.8
122.8
196.6
1553
186.7
174.5
264.3
157.5
81.1
227.8
600.9
730.2
408.1
752.3
226.6
332.2
336.7
244.3
208.2
734.2
312.3
296.2
Table 5.1. (continued)
Home
range Age years) at Adult Home range sze
ID# Sex Capture dae year first capture weight (kg) Locations (kI
Bobcats
M01' M 3/1/86 1986 Adult 93 48.9
M02' M 3/2/86 1986 Adult 10.0 95 17.8
MO05 M 9/1/86 1987 Adult 57 16.6
M08' M 3/3/87 1987 Adult 12.7 32 66.9
F03' F 3/17/86 1986 Adult 99 18.9
F06' F 2/27/87 1986 Adult 10.2 34 7.0
F07' F 2/25/87 1987 Adult 9.1 40 17.3
F09' F 3/5/87 1987 Adult 10.4 20 12.7
'Residt adult
2on-rproductiv
'Kiled before frt liter
mnsmitt w ied before fsit iter
'Non- ident adult
'Not ued inl cul ion ofme n
Table 5.2. Analysis of variance and Duncan's multiple range test results for comparisons of south Florida bobcat, black bear, and panther
seasonal home ranges (P=0.05) Means followed by different letters are significantly different from means in the same column.
Species/gender groups Winter (n) Summer (n) Fall (n) Fvalue p
Male panthers 319.3 (23)A 329.1 (24)A 330.6 (22) A 0.06 0.942
Female panthers 105.3 (53)B 91.1 (53)B 89.0 (51) BC 1.29 0.277
Male bear 47.2 (29)C 94.4 (19)B 172.2 (24) B 932 0.0003
Female bears 5.5 (33)C 15.6 (27)C 36.4 (37)C 11.77 <0.0001
Male bobcats 14.9 (5)C 32.5 (3) BC 9.8 (3)C 2.59 0.136
Female bobcats 9.0 (4)C 7.3 4)C 5.1 (3)C 0.697 0.526
Table 5.3. Seasonal home range sizes of male and female black bears in southwest Florida, 1991-1994. Means followed by different
letters are significantly different from other column means (Duncan's multiple range test, P=0.05).
Mean home range size (km)
Season Males Females
Winter 47.2 A 5.4 A
Summer 94.4 AB 15.6 AB
Fall 172.2 C 36.4 C
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
Table 5.4. Winter home range sizes of adult female black bears in Southwest Florida, 1992-1994.
Home range ize k. A)
Bear ID# Year With natal den Without natal den
F02 1992 0.9
F02 1993 20.8
F03 1993 0.03
F03 1994 8.3
F05 1992 27.7
F05 1993 12.8
F05 1994 1.3
F06 1992 2.4
F06 1993 0.5
F07 1992 15.8
F08 1992 1.0
F08 1993 5.9
F09 1992 0.5
F09 1993 2.6
F10 1993 8.0
F12 1994 20.2
F13 1993 0.2
F13 1994 7.9
F17 1993 11.0
F19 1993 21.3
Mean 1.3 (sd=1.9) 13.2 (sd=8.0)
Table 5.5. Frequency of interactions between male and female black bears in south Florida, 1991-1993, based on coincident radio-
locations and other factors.
Month
Age group J F M A M J J A S O N D
Number of coincident radiolocations between males and females
Allages 3 1 6 2 5 2 1 1 1
Adults 1 1 2 5 2 1
Ten Other evidence of a breeding season
Vulval swelling 1 1 1
Male wounds 2 4 1 1 1
Female wounds 1
Total 3 2 7 7 15 6 2 1 1 1
Table 5.6. Characteristics of Florida panther family dissolutions in south Florida, 1986-1993. Independence was defined as the first
month during which the arithmetic home range centers of the mother and kitten were >1 km apart. Ages of kittens are in months.
Family groups Characteristics of litters and separation
Litter Kitten age at Month of Ageat
Adult female ID Kitten ID size Date of capture capture separation separation
09 10 1 1/15/86 5 November 16
11 29 1 1/3/89 6 December 18
19 30 4 1/6/89 9 March 12
31 34 3 1/8/90 10 April 13
19 43 1 5/1/90 9 July 13
11 47 1 2/21/92 6 December 17
36 50 2' 2/4/92 8 May 11
31 48 & 52 2 5/5/92 6 December 14
40 54 22 2/10/93 10 Febnury 10I
'Sibling moved for captive Ireeding wopg at inil- aptie
'Sibling removed for captive breeding pmgnam at n iem rcapQue
dependencee Ipprenty caused by iabndrment afler #54s fnt 1aptm
1992 1993 A name nges W
1 lC2 I duOlt Finom Pnhw #a l, 1
A=Witw
S^ 'B A
I *" .
% ? ." *-
B A A :
****.., *
455 400 415 445 450 455 400 415 445 450 455 410
EW UTM
Figure 5.1. Seasonal home ranges of female panther #09 during 1992, 1993, and 1994.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 40(1)
2,910
"--. " 1992
.-.
2,900o '. A:
. Seasonal Home Ragee do
Adult Female Puather #11
C A-Winler
9-r mar
EW UTM
Figure 5.2. Seasonal home ranges of female panther #11 during 1992, 1993, and 1994.
WO SeaMonal Home Ranges d B, 1987
Male Panther #12 86
..,~ *~ * ..
/ B i "'.r
SIter
. / .' C=Fal .
.* AP *
450 46 470 40 4W0 460 470 40
EWUTM
Figure 5.3. Seasonal home ranges of male panther #12 during 1986 and 1987.
Seasonal Home Ranges of .**"* 1
Adult Male Pantler #1, 1986. 1987
2 A=ilh *
l:
B=SummWer a'
I A
z .
45 470 475 40 4 4 470 475 40 4
EW UTM
Figure 5.4. Seasonal o ranges of al pan #13 during 196 and 1987.
465 470 47 4 40 485 465 47 475 480 186
Figure 5.4. Seasonal home ranges of male panther #13 during 1986 and 1987.
MAEHR: ECOLOGY BOBCAT, BLACK BEAR, PANTHER
wm
2.M
2J00
2400
2892
405 400
EW UTM
Figure 5.5. Seasonal home ranges of female panther #32 during 1992, 1993, and 1994.
SeasonUa Home Rn0gs of
Adult Femle Panrthw #32, 1992
A-WhtW IB
B-ummr I
C-Fall .....-* ...***
/* I *
c.
." .*.
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