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innuuumiuw
of the
FLORIDA
MUSEUM OF
NATURAL HISTORY
NATURAL HISTORY OF THE
KATHARINE ORDWAY PRESERVE-
SWISHER MEMORIAL SANCTUARY,
PUTNAM COUNTY, FLORIDA
John F. Eisenberg and Richard Franz
Volume Editors
Volume 38, Pts. I & II, Nos. 1-9, pp. 1-260 1995
UNIVERSITY OF FLORIDA
GAINESVILLE
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Publication date: October 17, 1995
NATURAL HISTORY OF THE
KATHARINE ORDWAY PRESERVE-
SWISHER MEMORIAL SANCTUARY,
PUTNAM COUNTY, FLORIDA
John F. Eisenberg and Richard Franz
Volume Editors
Volume 38, Pts. I & II, Nos. 1-9, pp. 1-260 1995
FOREWORD
John F. Eisenberg' and Richard Franz2
The Katharine Ordway Preserve-Carl Swisher Memorial Sanctuary is
located in western Putnam County, Florida, roughly north latitude 29041' and west
longitude 820. The entire area includes approximately 3800 ha. Approximately 30
percent of the area, including the Mill Creek drainage, Ashley Prairie, and Putnam
Prairie, was donated to The Nature Conservancy by the Swisher-Wilcox family as a
memorial to Carl S. Swisher. The remaining tract, including uplands and sandhill
lakes, was purchased by the University of Florida Foundation from the Swisher-
Wilcox family by means of a donation from the Goodhill Foundation. Smaller
areas have been added since 1980 (Fig. 1). In the year 1980, The Nature
Conservancy and the University of Florida Foundation agreed to jointly manage the
tract as a single unit.
Amer-Indians clearly utilized this site for a very long period of time. Two
Indian mounds are identifiable. The presence of chert, worked into various
projectile points, suggests long-term seasonal occupancy, and the working of
materials transported through trade or other means are from Georgia. The
presence of dugout canoes dating to pre-Columbian times again attests to long-
term human occupancy. Settlement by immigrants began on a large scale after the
Armed Settlement Act of 1848, when people of European origin moved in and
began to develop agriculture. Mixed farming was practiced, and initially, cotton
was grown as a cash crop. Soil depletion was rapid, and the cotton boom was
SThe senior author holds the Katharine Ordway Chair of Ecosystem Conservation through the Florida Museum of Natural History and the
School of Forest Resources and Conservation, University of Florida, P. O. Box 117800, Gainesville FL 32611-7800, U.S.A.
2 The junior author is a Research Associate at the Ordway Preserve, Florida Museum of Natural History, University of Florida, P. O. Box
117800, Gainesville FL 32611-7800, U.S.A.
EISENBERG, J. F. and R. FRANZ. 1995. Forward. Pp. i-v in The Katharine Ordway-Carl Swisher
Memorial Sanctuary Volume: Herpetology and Mammalogy. Bull. Florida Mus. Nat. Hist. 38:00-00.
Mason
Figure 1. Wetlands and lakes of the Ordway-Swisher Preserve. The black outline delineates the preserve.
Lakes Barco, Rowan, Suggs, Anderson Cue, McCloud, Ross, Goose, Enslow and Brantley retained some
water throughout the drought
KEY TO THE LAKES AND PONDS OF THE KATHARINE ORDWAY PRESERVE
Recess Pond
South Fence Ponds
Hidden Pond
Lake Rowan
South Branch
Lake Barco
Rowan-Suggs Marsh
West Ford Field Pond
North Ford Field Pond
Suggs Lake
Fox Pond
One Shot Pond
Berry (or UF) Pond
Anderson Cue Lakes
Mill Pond
North Branch
North Mill Creek Pond
Two Mile Pond
Overflow
Small Pond
Mill Creek Ford
Lake McCloud
22. McCloud Sinkhole
Ponds
23. Ross Southside Pond
24. Ross-Goose Lakes
Canal
25. Blue Pond
26. Harry Prairie Sink-hole
Pond
27. Harry Prairie Pond
28. Big Clay Pit Pond
29. Ashley Hole
30. Porter's Hole
31. Timmon's Creek
32. Tucker's Neck Ponds
33. Tucker's Pond
34. Wall Lake
35. Hooks Pond
36. New Barn Ponds
37. Clear Pond
38. Gopher Ponds
39. Smith Lake Ponds
40. Smith Lake Lakes
41. Goose-Smith Lakes
Canal
42. Smith-Enslow Lakes
Canal
43. Piney Lodge Pond
44. Breezeway Pond
45. Breezeway Sandhill
Pond
46. Enslow-Brantley Lakes
Canal
47. Surprise Ponds
48. Brantley Pond
(also Fish Cove)
49. Depression Pond
50. Pole Cat Flats
51. Brantley North Ponds
52. Brantley Lake #1
(or Brantley Dark)
53. Brantley Lake #2
(or Brantley Clear)
54. Brantley Lake #4
55. Brantley Lake #3
essentially finished at about the time of the Civil War. Subsequent to that era,
small subsistence farming was carried on, but above all, exploitation of the longleaf
pine (Pinus palustris) commenced. This involved the collection of turpenes,
logging for saw timber, and the extraction of tree roots for rendering into "naval
stores." This was a very typical pattern for land exploitation in the coastal plain of
the southeast and not unique to north central Florida.
In the 1930s, the late Carl S. Swisher assembled a large tract of land,
including about 100 km2 of which the present preserve was a part. This land was
used in a recreational sense for fishing, but some attempts at agriculture also were
made, although not on a large scale. The pine uplands were burned on an irregular
schedule, as was customary to reduce fuel loads, thereby mitigating the affects of
lightning-induced wild fires. In 1980, The Nature Conservancy and the University
of Florida Foundation entered into a joint agreement for land management. The
main responsibility for management practices fell to the School of Forest Resources
and Conservation and the Florida Museum of Natural History.
Although some ecological research was initiated on the Preserve as early
as 1981, a concentrated effort at research and management was initiated in 1983.
At this time, a rotational burn schedule was developed whereby selected tracts on
the uplands, ranging in size from 120 to 200 acres, were burned on a three-year
rotation. Vegetational measurements allowed us to ascertain the extent to which
the survivorship of longleaf pine seedlings was favored over that of turkey oak
(Quercus laevis) seedlings. The burning schedule was aimed at enhancing the
growth of longleaf pine to restore the upland tracts to a longleaf pine/wire grass
(Aristida sp.) savannah. After 10 years, it is clear that the burn treatment has
indeed enhanced the growth of longleaf pine, and in the uplands, we are gradually
observing a dominance of longleaf pine at the expense of the turkey oak.
During the interval 1982-1992, numerous research projects were
conducted on vertebrates and invertebrates resident within the boundaries of the
Preserve. In this part of Florida, one is accustomed to annual variation in total
rainfall, but by 1987 it was clear that we were in an interval of rainfall deficit (Fig.
2). The drainage from Lake Melrose into the preserve derives from a wet prairie to
the west (Levi Prairie), and within the preserve, meanders in a northeasterly arc
via Mill Creek to exit at the northeast corner of the preserve from Putnam Prairie
to Goodson Prairie, and thence via the Etonia Creek system to the St. Johns River
(Fig. 1). Rainfall was below average for the years 1984 through 1987. Although
1988 was an excellent year, 1989 and 1990 were below average so that even the
rains of 1991 did not restore the lakes (Fig. 2). The smaller sandhill lakes not
connected with the major drainage system became dry by 1988. The larger lakes
within the major drainage system at the west end of the preserve (Rowan, Suggs,
Ross and Goose lakes) held water. Since many of the larger bodies of water, Lake
Ashley and Wall Lake, are shallow, the final drying of lakes once they had
achieved a critical level, was rather rapid.
(cm) (in)
175 70-
150 60-
S125 50-
100 40-
75 30-
50 20-
25 10-
82 83 84 85 86 87 88 89 90 91 92 93
Year
Figure 2. Annual rainfall as measured at Gainesville, Florida. The horizontal line represents the 70-year
average for the area.
In 1983, we had documented the existence of 53 bodies of water
(exclusive of canals). By 1992, only 9 basins held water, and these were all rather
large. As some of the shallow bodies dried out, vegetational succession was rapid,
and by 1992, small saplings of various lake fringe tree species were appearing
among stands of grass and dog fennel (Senecio sp.). Some of our major study sites
were profoundly affected by the drought. Smith Lake, and the associated Smith
Lake Sandhill, is such a case. Breezeway Pond disappeared as well. Sampling
areas for small mammals, including Ross Lake and Ashley Transect, showed no
major vegetational changes, although Lake Ashley went dry, and vegetational
succession on the lake bed has occurred. The upland Anderson-Cue study area was
very little affected.
The drying of the lakes has created locally catastrophic situations.
However, the sandhill communities exhibit a very different picture. Most
vertebrate populations that were not dependent on temporary ponds have exhibited
persistence and shown resilience under these adverse conditions. The north
Florida xeric-adapted species, including the gopher tortoise (Gopherus
polyphemus), spade-foot toad (Scaphiopus holbrooki), and the Florida mouse
(Podomysfloridanus), exhibit persistence even in the face of a prolonged drought.
This does not imply that these vertebrates are unaffected, but does reinforce the
notion that the xeric-adapted community has been under an extraordinarily long
period of selection to face such fluctuations in precipitation. Vertebrate species
dependent on lacustrine habitats are obviously at a disadvantage and during the
drought declined in numbers and, in some cases, became locally extinct. Aspects
of the biology of vertebrates on the Preserve will be explored within this volume
with case-by-case discussion of the effects of the drought.
TABLE OF CONTENTS
No. Title Page
PART I
An introduction to the amphibians and reptiles of the Katharine Ordway
Preserve-Swisher Memorial Sanctuary, Putnam County, Florida
R F ran z ..................................................................................................... 1
1 The ecology of a sandhills population of the eastern narrow-mouthed
toad, Gastrophryne carolinensis, during a drought
C .K D odd, Jr. ..................................................................................... 11
2 Seasonal abundance and habitat use of snakes in xeric and mesic
communities of north-central Florida
C.K D odd, Jr., & R Franz.....................................................................43
3 Vegetation of selected upland ponds in north and north-central Florida
L. LaClaire.......................................... .................. ........................... 69
4 Nesting ecology, female home range and activity, and population
size-class structure of the gopher tortoise, Gopherus polyphemus,
on the Katharine Ordway Preserve, Putnam County, Florida
L L Sm ith ......................................................................................... 97
5 Home range, habitat use, and behavior of the eastern diamondback
rattlesnake (Crotalus adamanteus) on the Ordway Preserve
W W Timm erm an.............................................. .......... 127
PART H
An introduction to the mammalian species of Katharine Ordway
Preserve-Swisher Memorial Sanctuary
J.F. Eisenberg....................................................................................... 165
6 Activity, movement, and home range of Virginia opossums
(Didelphis virginiana) in Florida
J.T R yser ....................................................................................... . 177
7 Habitat use and home ranges of Podomysfloridanus on the
Ordway Preserve
C Jones.......................................................................................... . 195
8 Neotomafloridanafloridana:: Natural history, ecology, and
movements in north-central Florida
L. H aySm ith ..........................................................................................211
9 Habitat use by raccoons (Procyon lotor) in a sandhill/wetland mosaic
of north-central Florida
S. W alker ................................ ............................ 245
AN INTRODUCTION TO THE AMPHIBIANS AND REPTILES
OF THE KATHARINE ORDWAY PRESERVE-SWISHER
MEMORIAL SANCTUARY, PUTNAM COUNTY, FLORIDA
Richard Franz'
The five accompanying papers present information from several recent
studies on amphibians and reptiles conducted on the Katharine Ordway Preserve-
Swisher Memorial Sanctuary (=Preserve), located about 5 km SE of Melrose,
Putnam County, Florida. Three of these papers represent theses that were
originally submitted to the University of Florida's Department of Wildlife and
Range Sciences (LaClaire 1992; Smith 1992; Timmerman 1989). The results of
initial efforts at the Preserve are contained in 31 reports and published papers,
which provide baseline herpetological information for future studies (Table 1).
The herpetological list, developed over a 10-year period (1983-1993),
includes 27 amphibians and 46 reptiles (Appendix 1). Its formulation represents
the efforts of many colleagues, including Ray E. Ashton, Jr., Michael Blouin,
Russell Burke, Bert Charest, C. Kenneth Dodd, Jr., Douglas Eifler, Kevin Enge,
Linda V. LaClaire, Paul E. Moler, Scott Pitts, Jan Ryser, Lora L. Smith, Karl
Studenroth, James Stuart, John Thorbjarnarson, Kent Vliet, and Walter W.
Timmerman. Amphibians and reptiles, scavenged from roads or accidentally
killed in pitfall or funnel traps, were preserved as vouchers and placed in the
herpetological collections of the Florida Museum of Natural History and the
National Museum of Natural History, Smithsonian Institution. The common and
scientific names used in this text follow Conant and Collins (1991).
The list was developed from direct observations and from animals found
during specific studies or caught in pitfall, wire funnel, and Iverson turtle traps.
Traps, set in terrestrial habitats, usually were in association with constructed drift
fences or set along natural barriers such as fallen trees. Traps produced more than
20,000 captures of 57 species caught over 150,000 trap days (one trap=one trap set
SThe author is an Associate in Ecology at the Florida Museum of Natural History, University of Florida, P.O. Box I17800, Gainesville FL
32611-7800, U.SA.
FRANZ, R. 1995. An introduction to the amphibians and reptiles of the Katharine Ordway Preserve-
Swisher Memorial Sanctuary, Putnam County, Florida. Bull. Florida Mus. Nat. Hist 38, Pt. 1:1-10.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I
Table 1. List of reports and published papers concerning amphibians and reptiles of the Preserve.
Topic References
General survey
Ephemeral ponds
Trapping
Frog surveys
Bufo (quercicus)
Bufo terrestriss)
Cemophora
Cnemidophorus
Crotalis
Drymarchon
Elaphe
Gastrophryne
Gopherus
Notophthalmus (perstriatus)
Pituophis
Pseudemys floridanuss)
Seminatrix
Rana (areolata)
Franz 1991a
Moler & Franz 1987; Dodd & Charest 1988; Dodd 1992b; Franz 1991b;
LaClaire & Franz 1991; LaClaire 1992, 1995
Franz 1984, 1986; Humphrey et al. 1985; Dodd & Charest 1988;
Franz 1988; Franz et al. 1989; Dodd 1991, 1992b, 1993a, 1995;
Dodd& Franz 1995
Moler & Franz 1987; LaClaire & Franz 1991
Dodd 1994
Dodd 1994
Stuart & Dodd 1985
Dodd 1992a, 1993b
Timmerman 1989, 1990, 1995
Dodd 1988
Franz 1988
Dodd 1995
Eisenberg 1984; Franz 1984, 1986a; Ultsch & Anderson 1986;
Jones & Franz 1990; Smith 1992, 1995; Dodd 1993a
Dodd 1993a
Franz 1984, 1992
Franz 1986b
Dodd 1993c
Franz 1984, 1986a; Franz et al. 1988
for one 24-hr period).
The frog trapping data base was
supplemented by
vocalization surveys, which were conducted weekly between March 1983 and
March 1985 and irregularly in March and April 1993.
The habitats on the Preserve include high pine sandhills, xeric oak
hammocks, mesic hardwood hammocks, sandhill ponds and lakes, swamp forests,
and dark water ponds, lakes, and marshes (Franz and Hall 1991). About 15-20%
of the Preserve has been severely altered by agriculture. Mesic hardwood
hammocks, swamp forests, and darkwater habitats are restricted to the Mill Creek
valley. The Mill Creek originates in Lake Melrose (west of the Preserve) and flows
across the Preserve in an easterly direction (Fig. 1). This intermittent creek is an
upper tributary of the Etoniah-Rice Creek drainage, an important tributary of the
lower St. Johns River. Sandhill lakes are generally isolated with respect to one
another and to the darkwater flow-through system. There are no flatwoods and
permanent streams or springs on the property.
The Preserve includes a modest herpetofauna of mostly upland and aquatic
species (Appendix 1). The composition of this fauna reflects the Preserve's
geographical position on a N-S trending series of sand ridges that lie along the
FRANZ: INTRODUCTION TO ORDWAY HERPETOLOGY
Table 2. List of 24 species of amphibians and reptiles that are known to occur in the area contiguous with
the Preserve, but are not recorded from the property.
Putnam Inappropriate Possible
Species County Rare habitat additions
Ambystoma cingulatum + +
Ambystoma talpoideum +
Ambystoma tigrinum + +
Desmognathus auriculatus + +
Pseudobranchus striatus ? +
Pseudotriton montanus + + +
Pseudacris nigrita + +
Pseudacris ornata + +
Clemmys guttata + + +
Sternotherus minor + +
Eumecesfasciata + + +
Ophisaurus compressus + + +
Farancia erytrogramma + + +
Heterodon simus + +
Lampropeltis getula + +
Lampropeltis triangulum + ? +
Regina rigida + +
Rhadinaeaflavilata + +
Stilosoma extenuatum + +
Storeria dekayi +
Storeria occipitomaculata + +
Virginia striatula 7 +
Virginia valeriae +
Crotalus horridus + +
Total Species 16 10 13 13
eastern margins of the the old Northern Highlands. Six species of amphibians
dwell in upland terrestrial habitats and use ephemeral ponds as breeding sites,
while 13 of the reptiles are primarily associated with upland habitats, particularly
long pine sandhills. Most of the aquatic amphibians and reptiles occur in lentic
habitats, particularly in weedy lake conditions. Two species (Eleutherodactylus
planirostris and Hemidactylus garnotii) are exotic in Florida.
Most amphibians and reptiles on the Preserve are common in appropriate
habitats, although three amphibians and five reptiles are known from fewer than
five sightings: Notophthalmus viridescens 1; Pseudobranchus axanthus 1; Hyla
chrysoscelis 1; Terrapene carolina 1, Trachemys script 1, Ophisaurus attenuatus
2, Drymarchon corais 2, and Agkistrodon piscivorous 4. The reasons for this
apparent rarity are unknown. Four regionally rare or depleted species maintain
viable populations on the Preserve: Notophthalmus perstriatus, Rana capitol,
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I
Gopherus polyphemus, and Pituophis melanoleucus. A fifth species, Drymarchon
corias, is both rare on the Preserve and rare in the region. The Preserve serves as
an important refugium for rare or declining species and may play an important role
in any future recovery efforts for them.
At least 96 species are known from the immediate area surrounding the
Preserve (Alachua, Bradford, Clay, and Putnam counties). Of these species, 25
remain unreported from the Preserve; 10 are regionally rare; 11 are associated with
habitats not present on the property; and 13 could potentially occur on the Preserve
(Table 2), although the chances of their presence are remote because sampling
efforts have been intense in the last 10 years.
The Preserve is a dynamic ecological system that lends itself to both short-
and long-term herpetological studies. As the list of papers suggests, there are
many opportunities for further studies on individual species, as well as on
herpetological communities. The Preserve welcomes researchers to submit
proposals to the Ordway Board and to participate in the establishment of a
herpetological research tradition on this property.
REFERENCES2
Ashton, R. E., Jr., and P. S. Ashton. 1981. Handbook of reptiles and amphibians of Florida. Part One. The
Snakes. Windward Publishing, Inc., Miami. 176 pp.
and 1985. Handbook of reptiles and amphibians of Florida. Part Two. Lizards, turtles ,
and crocodilians. Windward Publishing, Inc., Miami. 199 pp.
and 1988. Handbook of reptiles and amphibians of Florida. Part Three. The amphibians.
Windward Publishing, Inc., Miami. 191 pp.
Conant, R., and J. T. Collins. 1991. Reptiles and amphibians. Eastern/Central North America. Houghton
Mifflin Co., Boston. 450 pp.
Dodd, C. K., Jr. 1988. Drymarchon corais coupern (eastern indigo snake). Ecdysis. Herp. Rev. 19(4):84.
__ 1991. Drift fence-associated sampling bias of amphibians at a Florida sandhills temporary pond. J.
Herp. 25(3):296-301.
S1992a. Fluorescent powder is only partially successful in tracking movements of the six-lined
racerunner (Cnemidophorus sexlineatus). Florida Field Nat. 20:8-14.
1992b. Biological diversity of a temporary pond herpetofauna in north Florida sandhills. Biodiv.
Cons. 1:125-142.
S1993a. Cost of living in an unpredictable environment: The ecology of striped newts
Notophthalmusperstriatus during a prolonged drought Copeia 1993(3):605-614.
1993b. The effects of toeclipping on sprint performance of the lizard Cnemidophorus sexlineatus.
J. Herp. 27(2):209-213.
1993c. Population structure, body mass, activity, and orientation of an aquatic snake (Seminatrix
pygaea) during a drought J. Zool. 71:1281-1288.
1994. The effects of drought on population structure, activity, and orientation of toads (Bufo
quercicus and B. terrestris) at a temporary pond. Ethol. Ecol. Evol. 6:331-349.
1995. The ecology of a sandhills population of the eastern narrow-mouthed toad, Gastrophryne
carolinensis, during a drought Bull. Florida Mus. Nat. Hist. 38, PtI(1):11-41.
2 Not rferenreces re cited in text, but are offered here s a basis for future research.
FRANZ: INTRODUCTION TO ORDWAY HERPETOLOGY
__, and B. G. Charest. 1988. The herpetofaunal community of temporary ponds in North Florida
sandhills: Species composition, temporal use, and management implications. Pp. 87-97 in R. C.
Szaro, K. E. Severson, and D. R. Patton, eds. Management of amphibians, reptiles, and small
mammals in North America. Proc. Symp.,U. S. Forest Service, Tech. Rept. R-166.
_ and R. Franz. 1995. Seasonal abundance and habitat use of snakes in xeric and mesic communities
of north-central Florida. Bull. Florida Mus. Nat. Hist. 38, Pt. I(2):43-68.
Eisenberg, J. F. 1984. The gopher tortoise as a keystone species. Pp. 1-4 in R. J. Bryant and R. Franz, eds.
Proc. 4th Ann. Mtg. Gopher Tortoise Council.
Franz, R. 1984. The Florida gopher frog and Florida pine snake as burrow associates of the gopher tortoise
in northern Florida. Pp. 16-20 in D. R. Jackson and R. J. Bryant, eds. The gopher tortoise and its
community. Proc. 5th Ann. Mtg. Gopher Tortoise Council.
1986a. Gopheruspolyphemus (gopher tortoise). Burrow commensals. Herp. Rev. 17:64.
1986b. Pseudemysfloridana peninsularis (Peninsula cooter). Egg predation. Herp. Rev. 17:64.
1988. Habitat use, movements, and home range in two species of ratsnakes (genus Elaphe) in a
north Florida sandhill. Final Rept, Florida Game and Fresh Water Fish Comm., Nongame program.
61 pp.
1991a. Annotated list of vertebrates of the Katharine Ordway-Swisher Memorial Sanctuary,
Putnam County, Florida. Ordway Preserve Res. Ser., Rept 2, 50 pp.
1991b. Remember the drought? Florida Wildl., Nov.-Dec. (1991):10-12.
1992. Pituophis melanoleucus mugitus, Florida pine snake. Pp. 254-258 in P. E. Moler, ed. Rare
and endangered biota of Florida. Vol. III. Amphibians and Reptiles. Univ. Presses Florida,
Gainesville.
R. E. Ashton, Jr., and W. Timmerman. 1989. Behavior and movements of certain small sandhill
amphibians and reptiles in response to drift fences. Final Rept., Florida Game and Fresh Water Fish
Comm., Nongame program. 75 pp.
C. K. Dodd, Jr., and C. Jones. 1988. Rana areolata aesopus (Florida gopher frog). Movement.
Herp. Rev. 19:33.
_ and D. W. Hall. 1991. Vegetative communities and annotated plant lists for the Katharine Ordway
Preserve-Swisher Memorial Sanctuary, Putnam County, Florida. Ordway Preserve Ser., Rept. 3, 65
pp.
Humphrey, S. R., J. F. Eisenberg, and R. Franz. 1985. Possibilities for restoring wildlife of a longleaf pine
savanna in an abandoned citrus grove. Wildl. Soc. Bull. 13:487-496.
Jones, C. A., and R. Franz. 1990. Use of gopher tortoise burrows by Florida mice (Podomysfloridanus) in
Putnam County, Florida. Florida Field Nat. 18(3):45-48.
LaClaire, L. V. 1992. Ecology of temporary ponds in north-central Florida. M.S. Thesis, Univ. Florida,
Gainesville. 174 pp.
S1995. Vegetation of selected upland ponds in north and north-central Florida. Bull. Florida Mus.
Nat. Hist. 38, Pt. I(3):69-96.
_ and R. Franz. 1991. Importance of isolated wetlands in upland landscapes. Pp. 9-15 in M. Kelly,
ed. Proc. 2nd Ann. Mtg., Florida Lake Management Soc., Winter Haven.
Moler, P. E., and R. Franz. 1987. Wildlife values of small, isolated wetlands in the southeastern coastal
plain. Pp. 234-241 in R. R. Odum, K. A. Riddleberger, and J. C. Ozier, eds. Proc. 3rd Southeastern
Nongame and Endangered Wildl. Symp., Georgia Dept Nat. Res., Atlanta.
Smith, L. L. 1992. Nesting ecology, female home range and activity patterns, and hatchling survivorship in
the gopher tortoise (Gopherus polyphemus). M.S. Thesis, Univ. Florida, Gainesville. 104 pp.
1995. Nesting ecology, female home range and activity, and population size-class structure on the
Katharine Ordway Preserve, Putnam County, Florida. Bull. Florida Mus. Nat. Hist. 38, Pt I(4):97-
126.
Stuart, J. N., and C. K. Dodd, Jr. 1985. Life history notes: Cemophora coccinea copei (northern scarlet
snake). Coloration. Herp. Rev. 16:78.
Timmerman, W. W. 1989. Home range, habitat use and behavior of the eastern diamondback rattlesnake.
M.S. Thesis, Univ. Florida, Gainesville. 80 pp.
S1990. Radio-telemetry of the eastern diamondback rattlesnake in north Florida sandhills-a
preliminary report. Pp. 22-26 in C. K. Dodd, Jr., R. E. Ashton, Jr., R. Franz, and E. Wester, eds.
Proc. 8th Ann. Mtg. Gopher Tortoise Council.
1995. Home range, habitat use, and behavior of the eastern diamondback rattlesnake (Crotalus
adamanteus) on the Ordway Preserve. Bull. Florida Mus. Nat. Hist. 38, Pt. 1(5):127-158.
6 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I
Ultsch, G. R., and J. F. Anderson. 1986. The respiratory microenvironment in the burrows of gopher
tortoises (Gopherus polyphemus). Copeia 1987:787-795.
FRANZ: INTRODUCTION TO ORDWAY HERPETOLOGY
APPENDIX 1
Annotated list of amphibians and reptiles known to occur on the Katharine Ordway
Preserve-Swisher Memorial Sanctuary, Putnam County, Florida.
Habitat classification follows Franz and Hall (1991).
AMPHIBIANS
FAMILY Sirenidae
Pseudobranchus axanthus Netting and Goin, NARROW-STRIPED DWARF SIREN. Rare. Known only
from a darkwater lake (Tucker Pond).
Siren intermedia LeConte, LESSER SIREN. Probably common. Darkwater lakes and Mill Creek Swamp.
Siren lacertina Linnaeus, GREATER SIREN. Probably common. Darkwater lakes and marshes.
FAMILY Salamandridae
Notophthalmus perstriatus (Bishop), STRIPED NEWT. Uncommon. High pine sandhills. Breeds in
certain isolated sandhill ponds.
Notophthalmus viridescens piaropicola (Schwartz and Duellman), PENINSULA NEWT. Rare. Known
from two darkwater lakes (Hooks and Tucker ponds).
FAMILY Plethodontidae
Eurycea quadridigitata (Holbrook), DWARF SALAMANDER. Common. Xeric oak and mesic hardwood
hammocks, swamp forests, and occasionally high pine sandhills. Breeds in ponds, darkwater lakes,
and possibly Mill Creek.
Plethodon grobmani Neill, SLIMY SALAMANDER. Probably common. Mesic hardwood hammocks and
swamp forests.
FAMILY Amphiumidae
Amphiuma means Garden, TWO-TOED AMPHIUMA. Common. Darkwater lakes.
FAMILY Pelobatidae
Scaphiopus holbrooki holbrooki (Harlan), EASTERN SPADEFOOT. Abundant High pine sandhill, xeric
oak and mesic hardwood hammocks. Breeds in temporary pools.
FAMILY Bufonidae
Bufo quercicus Holbrook, OAK TOAD. Abundant High pine sandhills and xeric oak hammocks. Breeds
in darkwater and sandhill ponds.
Bufo terrestris (Bonnaterre), SOUTHERN TOAD. Abundant Xeric oak and mesic hardwood hammocks,
swamp forests, and ruderal habitats. Breeds in lakes, ponds, marshes, and Mill Creek.
FAMILY Leptodactylidae
Eleutherodactylus planirostris planirostris (Cope), GREENHOUSE FROG. Common. (Naturalized).
Most terrestrial habitats.
FAMILY Hylidae
Acris gryllus dorsalis (Harlan), FLORIDA CRICKET FROG. Abundant Margins of darkwater and
sandhill habitats. Occasionally found on upland sites.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I
Hyla chrysoscelis Cope, COPE'S GRAY TREEFROG. Rare. Known from one immature specimen caught
at a sandhill pond (Breezeway Pond).
Hyla cinerea (Schneider), GREEN TREEFROG. Abundant Primarily darkwater lakes and ponds.
Hyla gratiosa Leconte, BARKING TREEFROG. Common. Breeds in ponds that lack fish populations.
Hylafemoralis Sonnini and Laterille, PINE WOODS TREEFROG. Common. Breeds in darkwater and
sandhill ponds, and occasionally sandhill lakes.
Hyla squirella Bosc, SQUIRREL TREEFROG. Common. Breeds primarily in darkwater ponds and
marshes.
Pseudacris crucifer bartramiana Harper, SOUTHERN SPRING PEEPER. Common. Breeds primarily
along margins of darkwater ponds and lakes.
Pseudacris ocularis (Bose and Daudin), LITTLE GRASS FROG. Common. Breeds primarily along
margins of sandhill lakes and ponds.
FAMILY Microhylidae
Gastrophryne carolinensis (Holbrook), EASTERN NARROWMOUTH TOAD. Abundant Breeds along
the margins of darkwater and sandhill ponds and lakes.
FAMILY Ranidae
Rana capitol aesopus Cope, FLORIDA GOPHER FROG. Common. High pine sandhills. Breeds in ponds
that lack fish populations.
Rana catesbeiana Shaw, BULLFROG. Uncommon. Breeds primarily in small sandhill ponds.
Rana clamitans clamitans Latreille, BRONZE FROG. Common. Margins of darkwater lakes and in the
Mill Creek Swamp.
Rana heckscheri Wright, RIVER FROG. Uncommon. Darkwater lakes and in the Mill Creek Swamp.
Rana grylio Stejneger, PIG FROG. Common. Primarily in darkwater lakes and ponds, and to a lesser
extent in sandhill lakes and ponds.
Rana utricularia sphenocephala Cope, FLORIDA LEOPARD FROG. Abundant Breeds in most water
bodies on the property. Occasionally found on upland sites.
REPTILES
FAMILY Alligatoridae
Alligator mississippiensis (Daudin), AMERICAN ALLIGATOR. Common. Primarily in darkwater lakes,
and occasionally in sandhill lakes and ponds.
FAMILY Chelydridae
Chelydra serpentina osceola Stejneder, FLORIDA SNAPPING TURTLE. Probably uncommon.
Darkwater lakes.
FAMILY Kinosteridae
Kinosternon baurii palmarum Stejneger, STRIPED MUD TURTLE. Common. Primarily in darkwater
ponds and lakes.
Kinosternon subrubrum steindachneri Siebenrock, FLORIDA MUD TURTLE. Common. Primarily in
sandhill ponds and lakes and darkwater marshes.
Sternotherus odoratus (Latreille), COMMON MUSK TURTLE. Common. Darkwater and sandhill ponds
and lakes.
FAMILY Emydidae
Deirochelys reticularia chrysea Schwartz, FLORIDA CHICKEN TURTLE. Uncommon. Darkwater and
sandhill ponds and marshes.
Pseudemysfloridana peninsularis Carr, PENINSULA COOTER. Common. Primarily in sandhill ponds
and lakes, less common in darkwater habitats.
Pseudemys nelsoni Carr, FLORIDA REDBELLY TURTLE. Common. Primarily in darkwater ponds,
lakes and marshes.
FRANZ: INTRODUCTION TO ORDWAY HERPETOLOGY
Terrapene carolina bauri W.E. Taylor, FLORIDA BOX TURTLE. Rare. Known from one capture in the
lower Mill Creek Swamp.
Trachemys scripta scripta (Schoepff), YELLOWBELLY SLIDER. Rare. Known from one specimen
caught at Tucker Pond.
FAMILY Testudinidae
Gopherus polyphemus (Daudin), GOPHER TORTOISE. Common. High pine sandhill, old fields, and
occasionally xeric oak hammocks.
FAMILY Trionychidae
Apaloneferox (Schneider), FLORIDA SOFTSHELL Common. Darkwater and sandhill ponds and lakes.
FAMILY Gekkonidae
Hemidactylus garnotii Dum. and Bibr., INDO-PACIFIC GECKO. Rare. (Introduced). Known from one
specimen caught at Pole Barn.
FAMILY Polychridae
Anolis carolinensis carolinensis Voigt, GREEN ANOLE. Common. High pine sandhills, xeric oak and
mesic hardwood hammocks, and some ruderal sites.
FAMILY Phrynosomatidae
Sceloporus undulatus undulatus (Latreille), SOUTHERN FENCE LIZARD. Common. High pine
sandhills and xeric oak hammocks.
FAMILY Teidae
Cnemidophorus sexlineatus sexlineatus (Linnaeus), SIX-LINED RACERUNNER. Abundant Associated
with open sandy areas in most terrestrial habitats.
FAMILY Scincidae
Eumeces egregius onocrepis (Cope), PENINSULA MOLE SKINK. Common. High pine sandhills, xeric
oak hammock, and margins ofsandhill ponds.
Eumeces inexpectatus Taylor, SOUTHEASTERN FIVE-LINED SKINK. Common. High pine sandhills
and xeric oak hammocks.
Eumeces laticeps (Schneider), BROADHEAD SKINK. Common. Mesic hardwood hammocks, swamp
forests, and occasionally xeric oak hammocks.
Scincella lateralis (Say), GROUND SKINK. Abundant High pine sandhills and xeric oak and mesic
hardwood hammocks.
FAMILY Anguidae
Ophisaurus attenuatus longicaudus McConkey, EASTERN SLENDER GLASS LIZARD. Rare. Known
from two sightings in ruderal areas along Entrance Road.
Ophisaurus ventralis (Linnaeus), EASTERN GLASS LIZARD. Uncommon. Xeric oak hammocks and
margins of darkwater and sandhill ponds.
FAMILY Amphisbaenidae
Rhineura floridana (Baird), FLORIDA WORM LIZARD. Probably common. High pine sandhills and
xeric oak hammocks.
FAMILY Colubridae
Cemophora coccinea coccinea (Blumenbach), FLORIDA SCARLET SNAKE. Uncommon. High pine
sandhills, xeric oak hammocks, and margins of sandhill ponds and lakes.
Coluber constrictorpriapus Dunn and Wood, SOUTHERN BLACK RACER. Common. Most habitats.
Diadophis punctatus punctatus (Linnaeus), SOUTHERN RINGNECK SNAKE. Uncommon. Xeric oak
hammocks, and margins ofsandhill ponds.
Drymarchon corais couperi (Holbrook), EASTERN INDIGO SNAKE. Rare. Known from two
individuals.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I
Elapheguttata guttata (Linnaeus), CORN SNAKE. Uncommon. High pine sandhills, xeric oak and mesic
hardwood hammocks, pine plantations, old fields, and around buildings.
Elaphe obsoleta quadrivittata (Holbrook), YELLOW RAT SNAKE. Probably common. Xeric oak and
mesic hardwood hammocks, swamp forests, wet prairies, and ruderal habitats.
Farancia abacura abacura (Holbrook), EASTERN MUD SNAKE. Uncommon. Darkwater lakes and
marshes.
Heterodon platyrhinus Latreille, EASTERN HOGNOSE SNAKE. Uncommon. High pine sandhills, xeric
oak hammocks, and old fields.
Masticophis flagellum flagellum (Shaw), EASTERN COACHWHIP. Common. High pine sandhills, xeric
oak hammocks, and old fields.
Nerodia floridana (Goff), FLORIDA GREEN WATER SNAKE. Uncommon. Darkwater lakes and
marshes.
Nerodia fasciata pictiventris (Cope), FLORIDA WATER SNAKE. Common. Darkwater and sandhill
lakes and ponds.
Nerodia taxispilota (Holbrook), BROWN WATER SNAKE. Uncommon. Darkwater lakes and Mill
Creek.
Opheodrys aestivus (Linnaeus), ROUGH GREEN SNAKE. Uncommon. Xeric oak and mesic hardwood
hammocks and ruderal habitats.
Pituophis melanoleucus mugitus Barbour, FLORIDA PINE SNAKE. Common. High pine sandhills and
ruderal habitats.
Regina alleni (Garman), STRIPED CRAYFISH SNAKE. Uncommon. Darkwater and sandhill lakes and
ponds.
Seminatrix pygaea pygaea (Cope), NORTH FLORIDA SWAMP SNAKE. Common. Darkwater and
sandhill ponds and lakes.
Tantilla relicta neilli Telford, NEILL'S CROWN SNAKE. Common. High pine sandhills, xeric oak
hammocks, and occasionally mesic hardwood hammocks.
Thamnophis sauritus sackenii (Kennicott), PENINSULA RIBBON SNAKE. Uncommon. Margins of
darkwater and sandhill ponds and lakes.
Thamnophis sirtalis sirtalis (Linnaeus), EASTERN GARTER SNAKE. Uncommon. High pine sandhills,
xeric oak and mesic hardwood hammocks, and margins of sandhill lakes.
FAMILY Elapidae
Micrurus fulvus fulvius (Linnaeus), EASTERN CORAL SNAKE. Common. High pine sandhills and
xeric oak and mesic hardwood hammocks.
FAMILY Crotalidae
Agkistrodon piscivorus conanti Gloyd, FLORIDA COTTONMOUTH. Rare. Known from four specimens
from the darkwater system.
Crotalus adamanteus Beauvois, EASTERN DIAMONDBACK RATTLESNAKE. Common. Xeric oak
and mesic hardwood hammocks and occasionally high sandhills.
Sistrurus miliarius barbouri Gloyd, DUSKY PIGMY RATTLESNAKE. Common. High pine sandhills,
xeric oak hammocks, and margins of darkwater and sandhill ponds and lakes.
THE ECOLOGY OF A SANDHILLS POPULATION
OF THE EASTERN NARROW-MOUTHED TOAD,
GASTROPHRYNE CAROLINENSIS,
DURING A DROUGHT
C. Kenneth Dodd, Jr.'
ABSTRACT
The eastern narrow-mouthed toad, Gastrophryne carolinensis, is a common inhabitant of sandhill
uplands in north-central Florida. From 1986 through 1990, I monitored a population of this species at a
0.16 ha wetland on the Katharine Ordway Preserve-Swisher Memorial Sanctuary, Putnam County, Florida.
The pond held water only 14 mo during the 60-mo study. A drift fence-pitfall trap system encircled the pond
basin to capture eastern narrow-mouthed toads as they entered and exited. A total of 5740 eastern narrow-
mouthed toads (including recaptures) were captured despite a severe drought during the latter years of the
study. In 1986 and 1988, approximately 900 eastern narrow-mouthed toads entered the pond, but the
numbers fluctuated substantially in the other years. Few multi-year recaptures were recorded, although two
eastern narrow-mouthed toads were captured four years after initial marking. Although eastern narrow-
mouthed toads were active during all months of the year, peak activity occurred from June through
September. Reproduction was successful only during the summer of 1985, and juveniles exited the pond
basin through the spring of 1986. The adult population size-class structure remained consistent throughout
the study, although the population size decreased. The adult sex ratio was male-biased in all years except
1990. Males were smaller than females in both snout-urostyle length (SUL) and weight, and differences
were significant among years and between sexes. Drought eliminated reproduction for five years and seemed
to reduce overall population size, but direct correlations between drought effects and natural stochastic
variation are not yet possible. My data suggest that G. carolinensis survives long-term droughts by
maintaining large populations scattered across a variety of habitats and because at least some individuals are
opportunistic, rather than philopatric, in their choice of breeding sites. Long-term studies and manipulative
field experiments will assist in answering some of the many questions raised by these results.
SThe author is a Research Zoologist, National Biological Service, Biological Science Center, 7920 NW 71st Street, Gainesville FL 32653,
U.S.A., and Curator (Courtesy) of the Florida Museum of Natural History, and an Associate Professor (Courtesy) with the Department of
Wildlife Ecology and Conservation, University of Florida.
DODD, C.K., JR. 1995. The ecology of a sandhills population of the eastern narrow-mouthed toad,
Gastrophryne carolinensis, during a drought. Bull. Florida Mus. Nat Hist., Biol. Sci. 38, Pt I(1):11-41.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
RESUME
El sapo de boca angosta del Este, Gastrophryne carolinensis, es un habitante comun de las tierras
altas arenosas del centro note de Florida. Yo monitored una poblaci6n de esta especie entire 1986 y hasta
1990 en un humedal de 0.16 ha en la Catherine Orway Preserve- Swisher Memorial Sanctuary, en el
Condado de Putnam, Florida. EL estanque contuvo agua durante s6lo 14 de los 60 meses de studio. Un
sistema de reja-trampa en la cual los sapos caian, se ubic6 rodeando todo el estanque con el objeto de
capturar sapos de boca angosta del Este, a media que estos entraban o salian del estanque. A pesar de una
several sequoia que ocurri6 durante los 1ltimos ainos de studio, se capture un total de 5740 sapos de boca
angosta del Este (incluyendo recapturas). En 1986 y 1988, aproximadamente 900 sapos de boca angosta del
Este entraron en el estanque, pero estos ndmeros fluctuaron substancialmente en los otros anfos. Aun cuando
dos sapos de boca angosta del Este fueron capturados durante cuatro anios despu6s del marcaje inicial, se
registraron escasas recapturas multianuales. Aunque los sapos de boca angosta del Este estuvieron activos
durante todos los meses del aino, el maximo de actividades ocurri6 entire junior y septiembre. La reproducci6n
fue exitosa s6lo durante el verano de 1985, abandonando los juveniles la cuenca del estanque a lo largo de la
primavera de 1986. La estructura etaria de la poblaci6n adult permaneci6 constant a lo largo del studio,
adn cuando el tamailo poblacional disminuy6. La raz6n de sexos estuvo sesgada hacia los machos en todos
los asios except 1990. Los machos fueron mis pequeflos que las hembras en longitud naso-urostilar y peso,
existiendo diferencias significativas entire ailos y sexos. La sequoia elimin6 la reproducci6n por cinco afos, y
pareci6 reducir el tamaflo general de la poblaci6n. Correlaciones directs entire los efectos de la sequoia y
variaci6n natural estocistica no son posibles todavia. Mis datos sugieren que G. carolinensis sobrevive
prolongadas sequoias a trav6z de la mantenci6n de grandes poblaciones repartidas a lo largo de una variedad
de habitats y ademas al menos algunos individuos son oprtunistas en vez de filopitricos en la elecci6n de sus
sitios reproductivos. Estudios a largo plazo y experiments manipulativos de campo permitiran responder
algunas de las muchas preguntas que surgeon de estos resultados.
INTRODUCTION
Droughts are common in Florida (Winsberg 1990), and have been an
important natural agent in selecting xeric-adapted plant species that comprise the
vegetation of many Florida ecosystems, including the sandhills community of
central and north-central Florida (Myers 1990). Although tree ring records are not
published for Florida, core samples from cypress trees (Taxodium distichum) in
other parts of the southeast suggest that droughts occur in cycles that alternate with
mesic or wet periods of varying duration (Stahle et al. 1988). Many Florida
animals, particularly amphibians and reptiles, were derived from xeric-adapted
western forms that migrated to the Southeast prior to the mid-Pleistocene
(Auffenberg and Milstead 1965; Meylan 1982; Webb 1990).
Although droughts occur on a regular basis, there are no quantitative data on
the responses of Florida's amphibian communities to prolonged drought. In other
areas, drought suppresses reproduction in amphibians (Fitch 1956), results in the
death of eggs or larvae prior to metamorphosis (Wright 1932; Tevis 1966; Heyer
1973; Shoop 1974; Seale 1982; Semlitsch 1983, 1987), and can lead to the decline
or extinction of local populations (Blair 1957; Corn and Fogelman 1984; Osborne
1989). For temporary pond-breeding amphibians, drought may play an important
role in population dynamics (e.g. Dodd 1993; Healy 1974; Harris et al. 1988;
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 13
Semlitsch and Wilbur 1989). Drought also has been suggested as a contributing
factor in the apparent worldwide decline in amphibians, particularly anurans.
Temporary ponds are dispersed throughout Florida's xeric uplands. These
ponds form in shallow clay-lined basins and typically fill during winter, spring, or
summer rains (LaClaire and Franz 1990). Summer thunderstorms are frequent but
scattered, and the often torrential rains help to maintain hydroperiod (i.e. the
amount of time standing water is in a wetland). As summer progresses, sandhill
ponds usually dry and remain without water through the autumn, unless rain from
a tropical depression or hurricane refills them. The wet-dry cycles are not regular,
however, and long periods with or without water are common.
Many ponds in sandhill habitats lack fishes because they are not connected
with other wetlands. In addition, an unpredictable and locally variable
hydroperiod results in variability in invertebrate populations, such that predacious
species may or may not colonize particular ponds. The composition and
population sizes of invertebrate species are not consistent within a geographic
region because of variation in local wetland hydroperiod coupled with variation in
predators' abilities to colonize spatially fragmented habitats. The absence of fishes
and the potential for reduced levels of invertebrate predation allow amphibians,
particularly those species that do not have well developed antipredator defenses
(Kats et al. 1988), to reproduce in temporary ponds (Pechmann et al. 1989;
Bristow 1991; Dodd 1993).
The importance of temporary ponds to a wide variety of wildlife is only
beginning to be appreciated (Moler and Franz 1988; LaClaire and Franz 1990). In
Florida sandhill communities, several species (e.g. Notophthalmus perstriatus,
Rana capitol aesopus) are obligate temporary pond breeders. Many other
amphibians, however, also breed in temporary ponds. From March 1983 through
February 1985, 13 anuran species bred in 10 temporary, isolated, clearwater,
sandhill ponds averaging 0.1-0.3 ha on the Katharine Ordway Preserve/Swisher
Memorial Sanctuary in Putnam Co., Florida (Moler and Franz 1988). Of 22
anuran species breeding in small isolated wetlands on the southeastern Coastal
Plain, 10 use temporary ponds as their principal or exclusive breeding habitat
(Moler and Franz 1988).
In 1985, I began a 5-year study of a temporary wetland in the "high pine"
uplands of north-central Florida. The objectives of the project were to measure the
species richness, diversity, and dominance of the community (Dodd 1992) and to
gather basic information on the population biology of species that use the pond and
adjacent uplands. However, a prolonged drought during the study provided the
opportunity to examine the effects of drought on the amphibian community.
In this paper, I report the results from data gathered on the eastern narrow-
mouthed toad, Gastrophryne carolinensis, the most abundant amphibian that
visited the pond. This toad is found from the Delmarva Peninsula south
throughout Florida and west to Missouri and Texas (Conant and Collins 1991).
The species is largely subterranean and secretive in habits, and its diet consists
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
almost entirely of ants and termites (Holman and Campbell 1958; Ashton and
Ashton 1985). Breeding occurs in a wide variety of temporary water habitats,
including ponds, ditches, and pools. Although commonly found in the Florida
sandhills (Campbell and Christman 1982; Mushinsky 1985), Gastrophryne occurs
in many other habitat types (Carr 1940; Anderson 1954).
Despite its large range and conspicuous nature during the breeding season,
there have been few studies of its ecology (Wright 1932; Anderson 1954) or even
of the timing of various activities, including reproductive phenophase (sensu
Mitchell 1979; Trauth et al. 1990). In other parts of the Southeast, data consist
mostly of observations on numbers at breeding ponds taken incidentally to other
studies (e.g. Gibbons and Bennett 1974; Gibbons and Semlitsch 1982, 1991) or of
anecdotal information on distribution, calling, coloration and feeding (Hecht and
Matalas 1946; Duellman and Schwartz 1958; Nelson 1972; Dalrymple 1988).
This paper presents data on the ecology of a Florida sandhills eastern narrow-
mouthed toad population and its response to a prolonged drought. These results
will form the baseline data for monitoring this population as part of a planned
long-term assessment of amphibian status.
ACKNOWLEDGMENTS
I thank R. Altig, M. Crump, D. Forester, R. Franz, J. Palis and J.H.K. Pechmann for reviewing drafts
of the manuscript and offering helpful suggestions. B. Charest, K. Enge, J. Stuart, M. Blouin, K. Studenroth,
and R. Burke assisted in data collection. I especially thank R. Franz for advice and shared information over
the years and L. LaClaire and L Smith for information on the vegetation and physical structure of
Breezeway Pond.
STUDY AREA AND METHODS
Field data were collected at Breezeway Pond, a 0.16 ha depression marsh
(Florida Natural Areas Inventory 1990) located in a shallow 1.3 ha basin on the
Katharine Ordway Preserve/ Swisher Memorial Sanctuary, Putnam Co., Florida.
The pond is surrounded by a "high pine" community dominated by longleaf pine
(Pinus palustris), turkey oak (Quercus laevis), and wiregrass (Aristida stricta) to
the south and west, a maidencane (Panicum hemitomon) meadow to the east, and a
xeric oak hammock dominated by sand live oak (Q. geminata) and laurel oak (Q.
hemisphaerica) to the north. Breezeway Pond is formed in a shallow sinkhole
depression and is not part of a flow-through drainage system. Water enters the
pond solely from rainfall and groundwater recharge. The hydroperiod is thus
dependent upon the level of the water table in the nearby surrounding uplands.
Water percolates downhill into the basin where it is trapped by stratified organic
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 15
soil layers beneath the soil surface (LaClaire and Franz 1990). The pond
continuously held water for two years prior to the initiation of my study, but its soil
profile suggests that periodic droughts are common (LaClaire and Smith unpubl.).
The pond area was enclosed by a 230-m drift fence made of galvanized metal
flashing (36 cm above ground, 10-15 cm below the surface). No vegetation
overhung the fence, and the fence and pond area were exposed to direct sunlight.
Vegetation was kept cut and away from the fence exposing bare white sand for
about 40 cm from the base of the fence in either direction. The distance from the
drift fence to the nearest forest cover is generally 20 m, but extends to about 50-60
m behind the Panicum meadow. Within the enclosure, herbaceous hydrophytic
vegetation dominated the basin although a few shrubs, including buttonbush
(Cephalanthus occidentalis), myrtle holly (Ilex myrtifolia), and wax myrtle
(Myrica cerifera), were present. Several sapling longleaf and slash pines (P.
elliottii) grew within the enclosure. Maidencane and carpetgrass (Axonopus
furcatus) comprised 76 percent of the ground cover on vegetation transects
(LaClaire and Smith unpubl.).
Pitfalls (19-1 black plastic buckets) were placed on opposite sides of the fence
at 10-m intervals following the procedures outlined by Gibbons and Semlitsch
(1982). In order to minimize the effects of direct sun, the buckets were partially
shaded with pegboard slanted over the openings in such a manner that there was
plenty of room for transit beneath the boards. Each board was laid flat across the
bucket opening on days when the pitfalls were not to be checked in order to prevent
desiccation of captured animals. Eastern narrow-mouthed toads were captured
even when the boards covered the bucket openings because the seals were not
complete.
The pitfalls were checked 5 days per week between 0700 h and 0900 h,
depending on season, from October 1985 through September 1990 (1,273 days;
83,950 bucket nights). A year was defined as extending from October of one year
through September of the following year (e.g. "1986" covers October 1985 through
September 1986) for purposes of analysis. This yearly partition corresponds better
than the calendar year with amphibian activity patterns in north-central Florida.
Frogs were measured in the field with a clear plastic ruler (snout-urostyle
length [SUL], defined as the tip of snout to the posterior portion of the urostyle)
and weighed to the nearest 0.1 g using a Pesola hand-held spring scale. Males
have a clearly visible black chin that is present in varying levels of intensity year-
round (Anderson 1954). In females the chin is mottled, light, and the same color
as the belly (Wright 1932). Females also occasionally contained eggs visible
through the ventral body wall. The sex was classified as "unknown" if there was
any question about the sex of the animal. Animals smaller than 21 mm SUL
generally were considered juveniles (Wright 1932; Anderson, 1954), although the
sex of some individuals was difficult to determine at 22-24 mm SUL (also see
Hecht and Matalas 1946). Anderson (1954) noted that G. carolinensis show adult
secondary sex characteristics across a range of sizes and that determining gonadal
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
activity solely from external characters is impossible. I marked frogs by clipping
toes using a year-specific cohort sequence; no more than one toe was clipped per
foot. I carefully examined all captured animals for regenerated toes. Frogs were
released on the opposite side of the fence from where they were captured.
In addition to biological data, I recorded maximum and minimum air and
water temperature and rainfall since the pitfalls were last checked, current weather
conditions, and the occurrence of cyclic weather patterns (e.g. cold fronts, severe
storms, etc.).
Eastern narrow-mouthed toads marked in one year and recaptured in another
year presented special data analysis problems, because I could not determine
whether an individual had been caught more than once during the second year.
Either combining or excluding counts of previously marked frogs with first-caught
frogs will give an imprecise picture of population structure and sex ratio of the
breeding population. In the results and discussion below, I arbitrarily chose to
exclude multi-year recaptures; descriptive statistics relate to previously unmarked
animals caught within a year cohort. Multi-year recaptures are treated separately
in the paper.
RESULTS
Hydroperiod and Rainfall
From 1985 to 1990, generally small amounts of rain falling in the vicinity of
Breezeway Pond resulted in short hydroperiods at various times of the year (Dodd
1992). Large lakes also dried as the water table dropped > 2.5 m throughout
north-central and northeastern Florida from 1988 to 1990. Although the
maximum recorded water depth at Breezeway Pond was 75 cm, the pond held
water for only 14 mo from January 1985 through September 1990 (Fig. 1). The
water table was located 60 cm below the ground surface of the bottom of the pond
in October 1989 (LaClaire and Smith unpubl.). By February 1991, the water table
had dropped to 2.5 m below the ground surface and the central pond area was
colonized by a thick growth of Panicum.
The driest months at Breezeway Pond were April and October, whereas the
wettest months generally were in the summer, except in 1987 and 1988 (Fig. 1).
Less than 300 mm of rain fell in any one month except in September 1988, when a
tropical depression brought 270 mm of rain in four days. Rainfall was sporadic,
however, and very dry months occurred at all times of the year, especially from
October 1988 through September 1990.
In the summer (mid-May through mid-September), thunderstorms provided
most of the rainfall in the vicinity of Breezeway Pond. However, rainfall from
thunderstorms was localized and, during the latter years of the study, was
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNECAROLINENSIS 17
500
ex
400
E
< 300 ex
-J
I-
< 200
100 x x
0
O J A J 0 J A J 0 J A J
851 86 I 87 1 88
500
400
E
300
e e
x
2 200
Ir
100
0 J A J 0 J A J
88 89 90
Fig. 1. Monthly rainfall totals at Breezeway Pond, Putnam Co., Florida, October 1985-September 1990. The
stippled bars at the top of the figure illustrate the duration of the hydroperiod. No water was present in the
pond at other times of the year. The stars indicate months with substantial movements of Gastrophryne
carolinensis into (e) or away from (x) the pond.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
insufficient to replenish groundwater depleted by regional drought. North-central
Florida experienced a record drought during the latter half of the study based on
hydrological data kept by the St. Johns River Water Management District. Other
than the 1988 tropical depression, no weather patterns during that period resulted
in substantial rainfall at Breezeway Pond.
Daily and Seasonal Activity
A total of 5740 eastern narrow-mouthed toads, including recaptures, were
captured between 1985 and 1990 (Table 1). Most were captured during the first
four years of the study, and captures declined dramatically in 1990 as the drought
progressed. Eastern narrow-mouthed toads were captured during all months of the
year (Table 2), although they were not captured in all months of any one year (Fig.
2). Juveniles were caught more often than adults during the winter months of
December through February.
Adult males and females entered and exited the pond at all times of the year
(Table 2). However, 98% of all adult captures occurred from May through
September from 1986 through 1990. During the 1986, 1988, and 1990 field
seasons, most activity occurred from June through September (Fig. 2). Juveniles
exited the pond basin in the autumn of 1985 and during the spring of 1986, but
entered the pond from September through early November 1988.
Adult males and females were active not only during the same months of the
year (Fig. 2), but also on the same days. A visual examination of capture records
from 1986 through 1990 for the months of June, July, and August revealed no
temporal differences in the daily capture of males and females. A representative
example of the daily capture data for males and females is shown for June 1989
(Fig. 3). Neither sex was active consistently before or after the other sex.
Although individuals might be active during very dry periods, rainfall
triggered an immediate response. When rain fell from May through September,
frogs became active and were encountered at the drift fence. For example,
Gastrophryne moved in large numbers on only 10 occasions in June from 1986
through 1990. On eight of these occasions, rainfall totaled 29 mm or greater
(Table 3). On the remaining two occasions, the rainfall occurred after long periods
without rain. Most eastern narrow-mouthed toads were captured when most of the
monthly rainfall was recorded (Table 3). Large numbers of toads moved to
Breezeway Pond only in the presence of some rainfall.
The presence of standing water within the pond basin had no effect on eastern
narrow-mouthed toad movements, i.e. animals went to the pond in mid-summer
whether water was present or not (Fig. 1). Frogs entering Breezeway Pond
encountered standing water only twice from 1985 through 1990, and in one of
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 19
Table 1. Captures of unmarked (first number) and marked (second number) Gastrophryne carolinensis at
Breezeway Pond, Putnam County, Florida, 1986-1990. If the sex of an animal could not be determined, it
was classified as "Unknown."
Year Males Females Juveniles Unknowns Total
1986 193/76 142/48 371 482/102 854/226
1987 180/164 189/107 1/0 9/3 379/274
1988 507/195 351/130 8/0 31/2 897/327
1989 219/122 181/120 240/35 640/277
1990 55/24 66/36 1/0 1/5 123/65
Total 1154/581 929/441 287/35 523/112 2893/1169
I An additional 1678 recently metamorphosed juveniles were not marked in 1986.
N = 2758
E Unknowns
D Juveniles
1 Females
[ Males
N = 1224
N = 917
N = 653
N = 188
ODFAJAODFAJAAJFAJAODFAJAODFAJA
1985 1986
1987
1988
1989
1990
Fig. 2. Monthly and annual variation in activity patterns of adult and juvenile Gastrophryne carolinensis at
Breezeway Pond, Putnam Co., Florida. Data combined for all captures (N=5740), entering and exiting.
1
LL 1
_I
S1
>
2
LL
O
Urr
Z
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
Table 2. Capture of Gastrophryne carolinensis entering and exiting Breezeway Pond, Putnam County,
Florida, by month, 1986-1990. The total includes animals for which the sex was not determined. N = 5740.
Total Adults Exit Adults Enter Juveniles
Month Exit Enter M F M F Enter Exit
Jan 1 10 0 0 1 0 9 1
Feb 6 8 2 0 0 1 7 3
Mar 12 25 1 3 4 5 14 7
Apr 0 86 0 0 7 4 72 0
May 195 285 11 10 64 43 164 170
Jun 1130 1018 190 125 364 318 125 737
Jul 507 254 235 138 96 71 7 40
Aug 358 456 192 117 218 187 1 11
Sep 470 230 242 200 83 128 8 3
Oct 361 141 8 8 8 6 115 341
Nov 75 91 6 4 3 2 79 65
Dec 6 15 0 0 0 0 15 6
Total 3121 2619 887 605 848 765 616 1384
100%
80%
60%
40% -
20%
0% .'
1 5 7 9 13 15 19 21 23 27 29
DATE
SI Males (197) M Females (129)
Fig. 3. Proportional capture of male and female Gastrphryne carolinensis at Breezeway Pond, Putnam Co.,
Florida, in June, 1989. Males comprised 60% of the sample. Both sexes always were captured on the same
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS
Table 3. Relationship between the number of adult Gastrophryne carolinensis captured and daily rainfall
during the month of June 1986-1990.
Rainfall Number % of Monthly
Year Date (in mm) Captured Capture Rain
1986 18-22 147 156 75.4 85.5
1987 15-18 2 96
22-26 42 60 68.7 75.9
1988 6-10 29 79
28 2 27 78.5 100
1989 5-14 51 139
20-23 108 89
26-28 67 53 86.1 96.1
1990 7-12 108 45
25-27 136 31 74.5 98.4
those years (1987), the pond dried in June. A cumulative high monthly rainfall
total also was not associated with movement to or away from the pond (Fig. 1).
The sole exception was associated with a September 1988 tropical depression that
drenched north-central Florida. Individual frogs probably went back and forth
between the pond basin and upland retreat sites, depending on weather conditions,
throughout the breeding season.
Most of the eastern narrow-mouthed toads that were captured at the
beginning of the activity season in May or June were unmarked (Figs. 4, 5).
However, the relative proportion of unmarked to marked animals neither remained
constant nor decreased, except in 1990. Instead, a second influx of unmarked
animals appeared in August and September. The proportion of unmarked to
marked animals changed from one year to the next as the activity season
progressed, but the within-year patterns were similar between the sexes (Figs. 4,
5).
Population Structure
The overall sex ratio of unmarked adult (> 23 mm SUL) eastern narrow-
mouthed toads was one female for every 1.30 males. A male bias in the sex ratio
was present in all years except for 1990 (Table 4). The sex ratio of unmarked
animals differed significantly from 1:1 in 1986 (y2=9.95, df=l, p =
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
1987 (98%)
100%
75% -
50%
25s '
0%
J FM AM J J A S N D
O]Males U (181) IMales R (74)
1988(97%)
100%
75%q
50%
25% -
JF M A M J J A S O N D
E-Males U (492) SMales R (186)
1990(87%)
75%
50%
J FMAM JJAS ND
]Males U (172) ]Males R (163)
1989(96%)
100%
75%
50%
25%-
I
0% I
JF M AM J J A S ON D
DMales U (214) EMales R (111)
Total 1986-1 990 (98%)
J F M A M J J A S N
lMales U (47) EMMales R (22)
J F M A M J J A S O N D
OMales U (1030) MMales R (516)
Fig. 4. Proportional capture of unmarked (U) to recaptured (R) male Gastrophryne carolinensis during the
principle activity season at Breezeway Pond, Putnam Co., Florida, 1986 1990. The number in parentheses
after the year is the percentage of the total number of males captured within that year.
0.0016), 1988 (X2=30.57, df=l, p < 0.0001), and in the overall sex ratio from 1986
through 1990 (X2=28.76, df=l, p < 0.0001). In 1990, the ratio was nearly
significant (X2=3.61, df=-, p = 0.0574). For recaptured animals, the adult sex ratio
was one female for every 1.29 males and was male-biased in all years except 1990.
1986(95%)
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS
1986(96%)
100%
75%
50%
25%
J F M A M J J A S O N D
E3Females U (1 39) OFemales R (431
1988(96%)
100%
75%
50%9,
25%
JF M AM J J A S O N D
FIFemales U (338) [Females R (125)
1990(97%)
100%
75%
50%
25%
0% -
J F M A M J J A S O N D
Female U (63) Females R (35)
jFemales U (63) MFemales R (35)
1987 (98%)
100%
75%
50%-
25%
J F M A M J J A S O N D
E Females U (183) E Females R (107)
1989(96%)
100% .
75%
25%
V I.
J F M A M J J A S O N D
DFemales U (175) 0Females R (112)
Total 1986-1 990 (98%)
100%
75%-
50% -
25%
J F M AM J J A S O N D
FFemales U (831) EFemales R (411)
Fig. 5. Proportional capture of unmarked (U) to recaptured (R) female Gastrophryne carolinensis during
the principle activity season at Breezeway Pond, Putnam Co., Florida, 1986 1990. The number in
parentheses after the year is the percentage of the total number of females captured within that year.
There was no trend toward a 1:1 sex ratio as the season progressed in any year
(Table 4).
Population size structure varied somewhat among years (Fig. 6). In 1987,
1988, and 1990, the population structure was unimodal with few or no juveniles
and very large animals among the unmarked toads. In 1986 and 1988, the
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
Table 4. Summary of sex ratio data within and among years for all Gastrophryne carolinensis captured at
Breezeway Pond, Putnam County, Florida, during the months of June, July, and August The tabulation
includes all adults captured within that month.
June July August
Year M F Ratio M F Ratio M F Ratio
1986 117 90 1.3:1 94 55 1.7:1 44 37 1.2:1
1987 110 117 0.9:1 91 35 2.6:1 88 82 1.1:1
1988 85 50 1.7:1 84 63 1.3:1 247 133 1.9:1
1989 197 129 1.5:1 41 27 1.5:1 27 40 0.7:1
1990 45 57 0.8:1 21 29 0.7:1 4 12 0.3:1
Table 5. Analysis of variance of differences in snout-urostyle length (SUL) and weight among years
between the sexes of unmarked adult Gastrophryne carolinensis, 1986-1990. No weight data were
available for 1987. Values are for Type II sums of squares.
Variable Year Sex Year*Sex
SUL F= 115.24 F= 186.53 F= 16.56
p=0.0001 p=0.0001 p=0.0001
4 df 1df 4 df
Weight F=46.85 F=329.52 F=1.43
p=0.0001 p=0.0001 p=0.2316
3 df Idf 3 df
population structure was bimodal with the appearance of recently metamorphosed
young from the 1985 breeding season (exiting Breezeway Pond in 1986) and from
immigrants from some other location in 1988 (entering Breezeway Pond in
September, October, and November). Despite the lack of reproduction at
Breezeway Pond from 1986 through 1990, the population structure did not shift
appreciably toward large adults as the study progressed. In 1990, a small number
of eastern narrow-mouthed toads came to the pond, but the adult size structure did
not differ from previous years.
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLNENSIS
Table 6. Descriptive statistics for snout-urostyle length showing number, range, mean, and standard
deviation (in mm) of unmarked Gastrophryne carolinensis caught at Breezeway Pond, Putnam County,
Florida, 1986-1990.
Year Males Females Juveniles Unknowns
1986
N
Range
Mean
S.D.
1987
N
Range
Mean
S.D.
1988
N
Range
Mean
S.D.
1989
N
Range
Mean
S.D.
1990
N
Range
Mean
S.D.
137
(22-33)
27.8
1.52
180
(22-34)
26.4
1.50
376
(24-31)
27.5
1.31
219
(24-32)
28.1
1.43
55
(24-30)
27.1
1.26
89
(23-35)
28.8
2.36
189
(21-34)
26.5
2.60
239
(24-34)
29.1
0.38
181
(24-35)
30.1
1.99
66
(25-33)
29.0
1.68
36
(14-19)
18.1
1.18
326
(20-33)
22.8
1.78
5
(21-26)
22.8
1.92
8
(11-14)
12.9
1.13
222
(11-24)
15.9
2.37
Significant differences in SUL and weights occurred among years and
between sexes (Table 5), except for the year*sex interaction in weight. Differences
among mean adult SULs and weights were generally small (Tables 6, 7). Adult
males were shorter and weighed less than adult females in all years, although the
difference was slight in 1987. The largest mean SUL for both males and females
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
Table 7. Descriptive statistics for weight showing number, range, mean, and standard deviation (in
mm) of unmarked Gastrophryne carolinensis caught at Breezeway Pond, Putnam County, Florida,
1986-1990. Weights were not recorded in 1987.
Year Males Females Juveniles Unknowns
N
Range
Mean
S.D.
988
N
Range
Mean
S.D.
N
Range
Mean
S.D.
1990
N
Range
Mean
S.D.
137
(1.0-2.9)
1.93
0.30
301
(0.6-2.5)
1.62
0.20
206
(1.1-2.8)
1.75
0.24
54
(1.2-2.7)
1.93
0.29
89
(0.8-4.8)
2.29
0.66
177
(1.2-3.0)
2.04
0.38
176
(0.9-3.2)
2.23
0.44
66
(1.5-3.4)
2.42
0.43
33
(0.2-0.7)
0.52
0.11
8
(0.1-0.3)
0.19
0.06
198
(0.1-1.0)
0.35
0.16
318
(0.5-2.5)
1.10
0.30
was in 1989, whereas the smallest mean SUL for both was in 1987. The largest
male was 32 mm SUL, whereas the largest female was 35 mm SUL. Adult females
weighed more than adult males in all years. Weights were greatest for adult males
in 1986 and 1990, and for females in 1990.
Multi-Year Recaptures
Most recaptured eastern narrow-mouthed toads were caught within the
same year they were marked (Table 1), but 134 multi-year recaptures were
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 27
A loo
o 1986 1987
137 M 180M
S 80 89F 189F
a-
36J 5U
R 60 326 U
r 40
z
14 18 22 26 30 34 21 25 29 33
SUL (mm) SUL (mm)
SMales EFemales OJuveniles MUnknowns
B 200
1988
374 M
1 50 239 F
1989
8J
219M 1990
) 100 181 55 M
222 J 66
LU 66 F
1 J
1 U
z 50
11 15 19 23 27 31 11 15 19 23 27 31 35 23 27 31
SUL (mm) SUL (mm) SUL (mm)
HMales N Females E Juveniles E Unknowns
Figure 6. Annual variation in size-class structure of Gastrophryne carolinensis at Breezeway Pond, Putnam
Co., Florida. A. 1986 -1987. B. 1988-1990. An additional 1679 juveniles < 15 mm SUL were captured in
1986. Note the difference in scale.
recorded (Table 8). Most multi-year recaptures were marked in one year and
observed during the following year. Multi-year recaptures included both
immigrants to and emigrants from the pond throughout the activity season, and
made it impossible to determine how often they were caught within a season.
The size-class distribution of toads captured after one year spanned nearly the
entire range of size classes captured during the study (Fig. 7). However, the size-
class distributions of eastern narrow-mouthed toads captured after two and three
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
20
Cr 15
uL
z 10
2 yr
3 yr
0 4 yr
21 22 23 24 25 26 27 28 29 30 31 32 33
SNOUT-UROSTYLE LENGTH (mm)
Figure 7. Size-class structure of multi-year recaptured Gastrophryne carolinensis at Breezeway Pond,
Putnam Co., Florida, 1986 1990. Recaptures occurred after 1 year (N = 88), 2 years (N = 12), 3 years (N
= 11), or 4 years (N = 2).
years were quite similar to one another and included only larger adults. Only two
toads were captured four years after marking.
For the three years with the most multi-year recaptures, recaptured males
were larger than unmarked males in 1987 (mean=26.6 mm, N=13) but smaller
than unmarked males in 1988 (mean=27.3 mm, N=27) and 1989 (mean=27.8 mm,
N=30). Lengths for multi-year recaptured females were larger in 1987 (mean=26.9
mm, N=10) and 1989 (mean=30.6 mm, N=17) but slightly smaller in 1988
(mean=29.0 mm, N=20) than unmarked females. The weights of multi-year
recaptured males were nearly identical with unmarked males in 1988 (mean=1.6 g,
N=11), but multi-year recaptured females were substantially heavier (mean=2.3 g,
N=6) than unmarked females. In 1989, female weight was nearly identical
between marked and unmarked (mean=2.2 g, N=17) animals, whereas unmarked
males weighed more than multi-year recaptured males (mean=1.6 g, N=30). The
sex ratio of multi-year recaptured animals in 1987 was one female per 1.3 males;
in 1988, one female per 1.35 males; and in 1989, one female per 1.76 males.
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNECAROLINENSIS
Table 8. Multi-year recapture data for Gastrophryne carolinensis at Breezeway Pond, Putnam
County, Florida, 1986-1990.
Year
Initially Total Year Recaptured
Marked Marked 1986 1987 1988 1989 1990
1986 847 23 20 11 2
1987 379 42 2 0
1988 893 34 0
1989 640 0
Reproduction and Size at Metamorphosis
Breezeway Pond held water only from 7 June through 13 December 1985
(189 day hydroperiod) and from 24 February through 19 June 1987 (139 day
hydroperiod) during the reproductive season of G. carolinensis. Juvenile eastern
narrow-mouthed toads left the pond in October and November 1985 and from
April through June 1986. These animals were derived from the 1985 juvenile
cohort. Eastern narrow-mouthed toads did not reproduce successfully in 1987,
because the pond dried before metamorphosis could be completed. The other times
that the pond held water (Fig. 1) were outside the breeding season of G.
carolinensis and no reproduction occurred from 1986 through 1990.
From September through November 1988, 146 unmarked juvenile eastern
narrow-mouthed toads were recorded at Breezeway Pond. Of these, 105 (72%)
were captured as they entered the pond. Because of their small size and the lack of
water for the previous 13 months, it is unlikely that the remaining 41 animals
originated from within the enclosed pond. I suggest instead that they probably
trespassed the fence (Dodd 1991). The movement of this large group of juveniles
occurred after a tropical depression in September 1988. All originated from other
breeding sites and were not part of any reproduction at Breezeway Pond during the
summer of 1988.
All of the juveniles captured in the autumn of 1985 as they left Breezeway
Pond were < 14 mm SUL. The long hydroperiod during the summer of 1985
allowed larvae to complete metamorphosis without the threat of desiccation, and
toadlets probably foraged in the pond basin for several weeks or months prior to
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
Table 9. Trap mortality of Gastrophryne carolinensis at Breezeway Pond, 1986-1990.
Year Male Female Juvenile Unknown Total
1986 0/269 0/190 178/1715 22/584 200/2758
7.25%
1987 0/344 3/296 1/1 7/12 11/653
1.68%
1988 2/702 3/381 0/8 20/33 25/1224
2.04%
1989 4/341 1/301 20/275 25/917
2.73%
1990 2/79 1/102 0/1 5/6 8/188
4.25%
Total 8/1735 8/1270 199/2000 54/635 269/5740
% 0.46 0.63 9.95 4.69
exiting. Thus, the size of the juveniles exiting the pond from the 1985 cohort
probably exceeded their size at metamorphosis. The smallest eastern narrow-
mouthed toad measured at Breezeway Pond was 11 mm SUL. If this size can be
taken as the minimum size at metamorphosis at Breezeway Pond, then the
juveniles that were captured in the spring of 1986 grew from 3-8 mm prior to
exiting the pond.
Mortality
Relatively few adult G. carolinensis died in bucket traps from 1986 through
1990 (Table 9). Most mortality occurred in the juvenile size class, particularly in
1986 as large numbers of juveniles left the pond basin. The chief cause of
mortality seemed to be from desiccation despite the presence of moist sponges in
the bucket. In the hot summer, particularly during periods of drought, sponges
often dried within 20 h of hydration. After desiccation, the principal mortality
source was predation by ants, spiders (Geolycosa sp.), and carabid beetles
(Pasimachus strenuus, P. subsulcatus, Dicaelus sp.). In most instances, it was not
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 31
possible to determine whether the invertebrate killed the toad or the predator
scavenged a carcass.
DISCUSSION
Life-history of Gastrophryne carolinensis
Population Size.-There are no comparable studies on the eastern narrow-
mouthed toad in Florida with which to compare the results of this study. At least
900 adult G. carolinensis visited the pond basin (unmarked animals with
allowances for a few animals presumed to trespass the fence; Dodd 1991) in each
of two of the five years that the fence was checked. The number of animals visiting
the pond in 1987 is inexplicably low in relation to 1986, 1988, and 1989. This
could be due to a natural population fluctuation, but it makes the interpretation of
the 1990 collection data difficult. The most parsimonious explanation for the low
pond visitation in 1990 is that the effects of the long-term drought were becoming
apparent. Alternatively, the low numbers in 1990 could represent a natural
fluctuation. The numbers of breeding adults and juveniles that complete
metamorphosis of pond-breeding amphibians are known to fluctuate widely (Shoop
1974; Gibbons and Bennett 1974; Semlitsch 1987; Pechmann et al. 1989;
Raymond and Hardy 1990; Pechmann et al. 1991).
Recaptures.-Relatively few G. carolinensis were recaptured. Most
recaptured individuals were captured in the same season as originally marked,
presumably as the toads crossed back and forth between the core of the pond basin
and refugia in the surrounding uplands. Other studies on Gastrophryne also report
low recapture rates (Anderson 1954; Fitch 1956; Franz et al. 1989). Freiburg
(1951) recaptured 33.5% of marked G. olivacea in his 1-year study but only
12.7% more than once. Fitch (1956) marked 1215 G. olivacea between 1949 and
1954, but only 13 "yielded series of records, well spaced, in two or more different
years." Of 69 tattooed G. carolinensis trapped in April and May in Louisiana, only
five were recaptured (Anderson 1954).
Gastrophryne carolinensis may regenerate clipped toes rapidly, become trap-
shy or otherwise learn to avoid recapture, move to breeding ponds only once or
twice within a 5-year period thus minimizing the chances of recapture, or have
very high mortality rates. Rates of toe regrowth are unknown, but little evidence of
regrowth was apparent in this study or in studies of G. olivacea (Freiburg 1951).
Unpublished data on movements based on cobalt tagging suggest that G.
carolinensis may be sedentary and trap-shy (Franz et al. 1989). G. carolinensis
also easily crawl vertically upwards (Wright 1932) and cross drift fences (Dodd
1991). Alternative forms of marking and long-term studies are needed to evaluate
capture efficiency and individual recognition.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
Low recapture rates in amphibian studies have led some authors to conclude
that mortality rates are very high from one year to the next (e.g. Given 1988).
Although G. carolinensis possesses noxious skin secretions (Garton and
Mushinsky 1979), many vertebrates and invertebrates probably prey on this
abundant resource. This species also seems particularly sensitive to desiccation
(Anderson 1954; Wygoda 1984). Mortality at the pond or in refugia certainly
occurs, but whether it accounts for the low multi-year recapture percentages cannot
be ascertained.
Seasonal Activity.-Some G. carolinensis were active throughout the year at
Breezeway Pond, although adult activity was greatly reduced from October through
April. Juveniles were active in all months, especially in the autumn, presumably as
they dispersed. Peak population activity occurred from June through September as
adults moved toward and away from Breezeway Pond. This period is similar to
that reported elsewhere for this species (Wright 1932), although the breeding
season extends from April through September in the southern parts of the range
(Anderson 1954; Mount 1975; Dundee and Rossman 1989). April and May were
very dry months at Breezeway Pond from 1986 through 1990, perhaps accounting
for the lack of activity in these months.
Activity of Gastrophryne is definitely influenced by rainfall (Deckert 1914;
Wright 1932; Freiburg 1951; Anderson 1954; Fitch 1954). Heavy rains from June
through September stimulated adult animals to move to breeding sites. Movement
occurred during the rainy period, and there was no evidence of a lag effect. The
amount of rain needed to trigger movement varied with previous weather
conditions. If rainfall was regular, high amounts of rain were required to stimulate
movement. However, during droughts, rainfall of as little as 2 mm stimulated
substantial numbers of toads to move toward or away from the pond.
Although small amounts of rainfall can trigger movements to breeding ponds
by amphibians (e.g. Semlitsch 1985; Dodd and Charest 1988; Sexton et al. 1990),
most G. carolinensis move to ponds only after heavy rains, except after prolonged
periods without rain. Rainfall in April and May was never greater than 20 mm on
any one day from 1986 through 1990 at Breezeway Pond. Amounts were generally
1-10 mm. Few G. carolinensis moved during these months, although eastern
narrow-mouthed toads breed in April and May elsewhere in Florida (Carr 1940;
Duellman and Schwartz 1958) and nearby southern Georgia (Wright 1932).
Presumably, movement and reproductive behavior would have commenced in April
or May at Breezeway Pond if heavy rainfall had occurred.
Two peaks of immigration by unmarked animals of both sexes were evident
annually from 1986 through 1989. The first occurred in June, and the second
occurred in August. Two hypotheses are possible. The first is that two temporally
segregated groups of toads breed in Breezeway Pond. Alternatively, the August
pulse of unmarked animals represents toads that bred elsewhere and were moving
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 33
through the area on their way to terrestrial refugia. No August peak was observed
in 1990, but its absence might have been a consequence of drought.
One way to test these hypotheses would be to mark animals with different
two-week cohort marks and resample the pond from June through September. If
the August toads remain in the pond for the same amount of time that June toads
remain, the first explanation is reasonable. However, if the August toads exit the
pond rapidly after initial capture, the second explanation is more appropriate.
Neither explanation seems better than the other in the absence of sequential
capture data, but the large movement of juvenile toads through Breezeway Pond in
the autumn of 1988 suggests that migration through the area by transitory animals
is possible.
Reproduction.-Gastrophryne carolinensis successfully reproduced in only
one year from 1985 through 1990. Except in 1987, reproduction was unsuccessful
because of the lack of standing water. In 1987, water was present in Breezeway
Pond from February 24 through June 19. Given that the larval period for the
eastern narrow-mouthed toad varies from 20 to 70 days (Wright and Wright 1949),
eggs deposited in April, May, or even early June might have had enough time to
hatch and for larvae to complete metamorphosis. However, little rain fell from
April through June, few G. carolinensis migrated to the pond, and environmental
conditions in the pond became more and more unfavorable for larval survival
(shallow water, with maximum water temperature reaching 400C which is only
slightly below the average critical thermal maximum for larval eastern narrow-
mouthed toads (Cupp 1980). If reproduction occurred, it was unsuccessful.
Population Size-Class Structure.-It is difficult to make statements about the
significance in the general lack of annual variation in population size-class
structure of G. carolinensis at Breezeway Pond. Little is known about the
population structure of G. carolinensis at other breeding or non-breeding sites.
Also, the composition of the population at a breeding site is biased at any point in
time because it is only a sample of the population in surrounding habitats (Crump
1982).
However, among-year differences have two explanations. First, the
population structure at a breeding site could be influenced by differences in annual
and seasonal variation in activity, reproductive behavior, and movements between
the sexes and among size classes. Second, environmental conditions may stimulate
or inhibit activity at the breeding pond. Although differences were not found, it is
hard to believe that these factors had no influence on the population structure of
eastern narrow-mouthed toads from 1986 through 1990 at Breezeway Pond.
If the 1985 cohort had been followed in subsequent years, it might have been
possible to monitor age-class changes in the population structure. However, the
population structure remained nearly identical from 1986 through 1990 despite the
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
effects of drought and lack of recruitment. If the 1985 cohort had any effect on the
population's size-class or age structure, it was not apparent.
Sex Ratio.-Skewed sex ratios have been observed in other Gastrophryne
populations. Anderson (1954) also reported a male bias of eastern narrow-
mouthed toads trapped in Louisiana, but he captured the sexes in a 1:1 ratio by
hand. Freiburg (1951) captured more females than males in three of the four
months that he sampled.
Male frogs are generally more abundant at breeding sites than females
(Crump 1982; Woodward 1984 and references therein) and remain for longer
periods of time. However, a drift fence should capture all animals irrespective of
the length of time that they remain at the breeding site. Thus, in the absence of a
priori reasons to suspect that the sex ratio is different from 1:1 in the local
population of eastern narrow-mouthed toads, a skewed sex ratio over the course of
a breeding season was not expected. The preponderance of females caught after
August 1989 also is difficult to explain. I suggest several hypotheses that might
account for the observed skewed sex ratios.
First, the actual sex ratios really may be skewed, and the capture data mirror
the population's sex ratio, although sex ratio theory suggests that this is not
typically the case for iteroparous species (Fisher 1930). Alternatively, males may
move more often and remain at the breeding site longer than females. However, if
males move more often than females, they should be exposed to greater risks of
predation and desiccation. If they continued to do so during the early stages of a
severe multi-year drought, male mortality might be greater than female mortality
and lead to skewed sex ratios as the drought progressed. Finally, there may be
different tendencies between the sexes in their propensity to move to breeding sites,
especially during an environmental stress. For example, males might be less likely
than gravid females to leave secure refugia and move to breeding sites during
drought conditions. Also, individuals may not breed every year (Bull and Shine
1979; Gill 1985). One of the cobalt tagged adult females followed by Franz et al.
(1989) for more than one year lived 20 m from Breezeway Pond but never went to
the pond or made any other long-distance movements. Unfortunately, available
data are not sufficient to select among these hypotheses.
Individual Size.-Breezeway Pond G. carolinensis are within the SUL range
reported elsewhere in the literature for this species (Hecht and Matalas 1946;
Wright and Wright 1949; Anderson 1954; Duellman and Schwartz 1958).
Anderson (1954) reported a maximum size of 32.2 mm for males and 34.3 mm for
females in Louisiana. Weights have never previously been reported, except for five
G. carolinensis used in experiments on evaporative water loss (Wygoda 1984).
Sexual dimorphism is common in anurans, with males usually smaller than
females (Shine 1979; Duellman and Trueb 1986).
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 35
Gray (1989) suggested that the mean body size of numerically dominant
species should be reduced during an environmental perturbation. G. carolinensis
is clearly the dominant species in the amphibian community at Breezeway Pond
(Dodd 1992). However, the mean body size (both SUL and weight) did not change
significantly during the study. In fact, the greatest weights occurred in 1990, the
year of the most severe drought effects, although the population size declined.
These results mirror those obtained for the striped newt at the same site (Dodd
1993). Hence, my data do not substantiate Gray's (1989) predictions.
Longevity.-The oldest wild-caught G. carolinensis at Breezeway Pond were
at least in their fourth year, the same age that Fitch (1956) reported for G.
olivacea in Kansas. Eastern narrow-mouthed toads captured after four years were
probably in their first or second year when initially caught. Fitch (1956) suggested
that the plains narrow-mouthed toad might live a few years beyond four, and that
most of the breeding population consisted of 3-year olds. A similar scenario seems
reasonable for G. carolinensis at Breezeway Pond.
Mortality.-Trap mortality resulted primarily from desiccation. G.
carolinensis seem particularly prone to desiccation despite attempts to minimize its
impact. Smaller animals are more susceptible than larger animals. Anderson
(1954) noted similar results and suggested that desiccation made the toads more
vulnerable to predation by the ant Iridomyrmex humilis. Such a hypothesis seems
reasonable inasmuch as dehydration reduces locomotor capacity in frogs (Moore
and Gatten 1989). Invertebrate predation undoubtedly occurs in the confines of a
bucket, but its effects are unknown in wild populations.
Response to Drought
Drought, especially long-term drought, may have serious consequences for
amphibians that breed in isolated temporary ponds in sandhill habitats (Dodd
1993). This is because most Nearctic amphibians, including Gastrophryne, usually
lack special reproductive adaptations to resist or avoid drought conditions.
Because they are bound to water, a severe reproductive cost will be realized when
environmental conditions are not favorable for reproduction. Yet, drought occurs
regularly in the southeastern United States and is quite common in the Upper
Etonia Creek Basin that contains the Ordway Preserve (Motz et al. 1991).
Dodd (1993) suggested that drought might have three effects on populations
of striped newts, Notophthalmus perstriatus, sympatric with G. carolinensis in
upland sandhill habitats. Localized newt populations might be extirpated, newts
could move to other nearby breeding sites if available, or newts could outlast the
drought in favorable refugia and take advantage of predator-free habitats once the
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
drought ended. In this regard, striped newts exemplify a version of the "storage
effect" whereby reproduction is maximized during favorable periods and curtailed
at other times (Warner and Chesson 1985). Newts may outlast a drought in
reduced population size because interdemic migration is rare and newts
presumably have a long life span (Gill 1985). Local extinctions undoubtedly occur
during very severe droughts, but it is rarely possible to prove this is responsible for
the absence of newts from what seem to human observers to be appropriate
breeding sites. Below, I examine whether G. carolinensis populations in dry
sandhill habitats might respond in a similar manner to droughts.
Localized Extinction.-Casual observations suggest that most aquatic
habitats that might be expected a priori to contain breeding adult G. carolinensis
usually do so under favorable conditions. Eastern narrow-mouthed toads were
found on other parts of the Ordway Preserve during the drought and still visited
Breezeway Pond 5 years after they last successfully reproduced in the pond. Still,
during severe droughts extending more than several breeding seasons, localized
extinction of eastern narrow-mouthed toad populations might occur. However, no
data on localized extinctions of this species are available. The extent to which the
eastern narrow-mouthed toads using Breezeway Pond constitute a reproductively
closed population is unknown, so the definition of what might constitute a
population-level local extinction is unclear.
If localized extinctions occur but breeding ponds are quickly recolonized, the
temporary loss of a portion of a breeding population, or even the entire breeding
population, might be overlooked without long-term monitoring. Environmental
perturbations or predation preclude successful amphibian reproduction in some
years (this study; Pechmann et al. 1989; Pechmann et al. 1991; Dodd 1993), but it
is unknown how long a population might persist without reproducing. The
average life span of G. carolinensis under natural conditions remains unknown.
Interdemic Migration.-Nothing is known of the potential for interdemic
migration of eastern narrow-mouthed toads. Individual Gastrophryne occasionally
may travel long distances (300-600 m in Fitch 1956; Franz et al. 1989). However,
G. carolinensis (N = 353) captured at drift fence arrays 40-290 m from Breezeway
Pond were never captured at the pond from 1987 to 1989, nor were toads marked
at Breezeway Pond captured at the arrays. Thus, even relatively short distance
movements were not demonstrated.
Non-reproductive movements of both G. carolinensis and G. olivacea seem
to be quite localized (Freiburg 1951; Fitch 1956; Franz et al. 1989). Fitch (1956)
estimated the home range of G. olivacea to be about 46 m in diameter whereas
two cobalt-tagged G. carolinensis near Breezeway Pond had home ranges
averaging only 273 m2. Presumably, breeding adults faced with a dry pond are
capable of traveling elsewhere, if appropriate habitats are nearby, but whether they
actually do so is unknown.
DODD: ECOLOGY OF SANDHILLS POPULATION OF GASTROPHRYNE CAROLINENSIS 37
Although many amphibians show site fidelity to a particular breeding pond
(Martof 1953; Shoop 1965; Gill 1978, 1985; Semlitsch 1981; Duellman and Trueb
1986; Smith 1987), this had not been demonstrated previously for G. carolinensis.
Anderson (1954) reported that a population of eastern narrow-mouthed toads in
Louisiana attempted to breed at the site of a pond bulldozed the previous year. In
the present study, multi-year recaptures suggest some degree of site fidelity in
breeding site choice. If site fidelity is strong, interdemic migration probably is not
significant. Even if most of the population never moves to another breeding site,
however, a few toads might do so. Only a few wandering reproductive toads could
recolonize a new or former breeding site.
Refugia.-Gastrophryne carolinensis could stay in terrestrial refugia until
drought conditions end, if they can live long enough to outlast the drought. The
two toads captured four years after initial marking are the longest lived individuals
reported from a free-ranging population of this species. Fitch (1956) also captured
several G. olivacea known to be in their fourth year and speculated that some
individuals can live a few more years. Droughts that result in the loss of breeding
sites more than four years in a row might begin seriously to deplete a local
population. If this is the case, the study at Breezeway Pond ended at a critical
juncture.
CONCLUSIONS
To understand how an amphibian population is affected by drought, it is
necessary to recognize that the frogs that visit a pond represent a fraction of the
total population (Crump 1982). The population of eastern narrow-mouthed toads
that inhabits the Breezeway Pond region includes juveniles, non-reproductive
adults, and breeding adults. The reproductive population of G. carolinensis
probably contains a large number of individuals dispersed at substantial distances
from a breeding site. The population is widely distributed, with toads dispersing
evenly toward the various environments surrounding the pond (sandhills, xeric
hammock, meadow) (Dodd unpubl.). Eastern narrow-mouthed toads have been
seen in sandhills more than 500 m from the nearest potential breeding location
(pers. obs.).
Amphibians living in unpredictable environments should be flexible in life
history traits (Wilbur 1972; Crump 1982). Unlike the sympatric striped newt
(Dodd 1993), I suggest that the eastern narrow-mouthed toad probably does not
survive a drought through a combination of long life span and opportunistic timing
of reproduction. Subterranean habits, the abundance of ants and termites for food,
a short larval period, and the ability to use a wide variety of temporary wetlands for
breeding probably allows G. carolinensis to colonize the otherwise harsh sandhills
BULLETIN FLORIDA MUSEUM NATURAL HISTORY 38(1)
of northern and central Florida. I further suggest that G. carolinensis survives
long-term droughts because of its large population size and use of a broad range of
habitats, and because at least some individuals are opportunistic, rather than
philopatric, in their choice of breeding sites. I predict that localized extinctions
occur during severe droughts at certain breeding sites, although this remains to be
proven.
Although the trend in amphibian community studies has been toward
controlled manipulative experiments (Jaeger and Walls 1989; Morin 1989; Wilbur
1989), the value of long-term ecological monitoring is increasingly recognized
(Franklin 1989; Taylor 1989). Franklin (1989) noted that long-term studies are
needed to examine ecological processes that are slow, rare, episodic, or which
contain high degrees of variability, or involve subtle and complex phenomena, or
to test and formulate theory. The response of the population of G. carolinensis at
Breezeway Pond and its surrounding uplands to episodic drought is certainly
complex, subtle, and probably extends over time. Population parameters (e.g. sex
ratio, age and size-class structure, larval duration, and survivorship) are certainly
variable, even without environmental uncertainty. Although lasting five years, this
study could not answer many important questions about this and other amphibian
species' responses to environmental perturbations.
Until monitoring encompasses longer time periods, the long-term effects of
environmental perturbations on a species or community must remain speculative.
If prolonged drought severely stresses amphibian communities, the response
probably lasts many years, and the effects probably vary locally and species-
specifically. On the other hand, short-term droughts may have no lasting effects
(Cypert 1961). Population recovery will depend on a drought's duration, the
presence of refugia, a species' colonization abilities and life history plasticity, and
its habitat requirements and their availability. These considerations are important
for determining the long-term effects of drought-induced declines in amphibian
populations. Separating natural fluctuations in community composition and
structure from human-caused or environmentally related declines will not be
possible without long-term monitoring studies. The baseline data gathered in the
present study provide an example of the information that will be needed.
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Winsberg, M. D. 1990. Florida Weather. Univ. Central Florida Press, Orlando.
Woodward, B. D. 1984. Arrival to and location ofBufo woodhousei in the breeding pond: Effect on the
operational sex ratio. Oecologia 62:240-244.
Wright, A. H. 1932. Life-histories of the Frogs of Okefinokee Swamp, Georgia. MacMillan Co., New
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and A. A. Wright 1949. Handbook of Frogs and Toads. Comell Univ. Press, Ithaca, New York.
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SEASONAL ABUNDANCE AND HABITAT USE OF
SELECTED SNAKES TRAPPED IN XERIC AND MESIC
COMMUNITIES OF NORTH-CENTRAL FLORIDA
C. Kenneth Dodd, Jr.,' and Richard Franz2
ABSTRACT
We studied the upland snake community on the Katharine Ordway Preserve-Swisher Memorial
Sanctuary during the years 1989 and 1990. A total of 220 wire-mesh funnel traps were deployed at seven
xeric and three mesic habitats for a total of 39,162 trap nights. Habitats were sampled from March or April
to September or November, depending on year and location. Fourteen species (276 individuals plus 53
recaptures) of snakes were captured, nearly all in traps, of which the five most abundant were Cemophora
coccinea, Coluber constrictor, Masticophis flagellum, Micrurus fulvius, and Sistrurus miliarius. The
high-pine snake-community was slightly more diverse and evenly distributed than that of the other xeric or
mesic habitats. Snakes were active throughout the sampling period but showed complex rather than strictly
modal patterns of activity. In general, there appears to be little seasonal or macro-level habitat partitioning
among the five most commonly trapped snakes. Neither monthly rainfall nor temperature appeared to
influence capture. The black racer (Coluber constrictor) was the most commonly trapped species in all
habitat types, with larger racers caught in more structurally diverse habitats. Sampling biases may account
for the lack of capture of certain species or the underrepresentation of species known to be more common
than capture data indicate. Funnel traps should be used in conjunction with other techniques to remove
sampling biases when inventorying and monitoring snake communities.
RESUME
Estudiamos la comunidad de culebras, habitante de las tierras altas en la Katharine Ordway Preserve-
Swisher Memorial Sanctuary, durante 1989 y 1990. Se install un total de 220 trampas de alambre
1
The senior author is a Research Zoologist, National Biological Service, Biological Science Center, 7920 NW 71st Street, Gainesville FL
32653, U.S.A., and and Courtesy Curator of Herpetology, Florida Museum of Natural History, University of Florida, P. O. Box 117800,
Gainesville FL 32611-7800, U.S.A.
2
The junior author is an Associate in Ecology, Florida Museum of Natural History, University of Florida, P. O. Box 117800, Gainesville
FL 32611-7800, U.S.A.
DODD, C. K., JR., and R. FRANZ. 1995. Seasonal abundance and habitat use of selected snakes trapped
in xeric and mesic communities of north-central Florida. Bull. Florida Mus. Nat. Hist. 38, Pt. I(2):43-67.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
tubulares en site habitats x6ricos y tres habitats m6sicos, por un total de 39.162 trampas-noche. Los
habitats fueron muestrados de marzo o abril, a septiembre o noviembre, dependiendo del aio y la localidad.
Se capturaron 14 species (276 individuos, ademis de 53 recapturas) casi todas en trampas, siendo las cinco
species mas abundantes Cemophora coccinea, Coluber constrictor, Masticophis flagellum, Micrurus
fulvius y Sistrurus miliarius. La comunidad de culebras de sitios altos con pinos, fue levemente mis diverse
y mas homog6neamente distribuida que las comunidades de otros habitats x6ricos o m6sicos. Las culebras
estuvieron activas a lo largo del period de muestreo, aunque mostraron patrons de actividad mas
complejos que estrictamente modales. En general, parece haber poca partici6n de habitat estacional o a un
nivel macro, entire las cinco culebras mas comunmente capturadas. Las captures no parecieron star
influenciadas por pluviosidad mensual ni temperature. La corredora negra (Coluber constrictor) fue la
especie mis comunmente atrapada en todos los tipos de habitats, siendo las corredoras mis grades
capturadas en habitats mas estructuralmente diversos. La ausencia de capture de algunas species o la
subrepresentaci6n de otras species conocidas como mis comunes que lo que indican los datos de capture,
puede deberse a sesgos de muestreo. Las trampas tubulares debieran ser usadas en conjunto con otras
t6cnicas con el objeto de remover sesgos de muestreo cuando se inventorean y monitorean comunidades de
culebras.
INTRODUCTION
Relatively few studies have focused on snake community ecology, especially
because of sampling difficulties (Vitt 1987). In order to fully appreciate the
importance of snakes in community organization, however, species richness,
abundance, and annual and seasonal variation in activity patterns must be
determined. Sampling a variety of habitats using standardized techniques helps
record variation in habitat use that is then subject to investigation using
experimental procedures.
At one time, the longleaf pine (Pinus palustris)-turkey oak (Quercus laevis)-
wiregrass (Aristida stricta) community stretched along the Atlantic and Gulf
coastal plain from Virginia south to Florida, including a major portion of the
Florida peninsula (Myers 1990), and westward to Texas. The community
comprised approximately 28.3 million hectares, of which less than 10 percent
remains (Croker 1979; Means and Grow 1985; Noss 1989). Interspersed within the
longleaf pine forests are other communities, such as hardwood and swamp forests
and xeric and mesic hammocks (Myers and Ewel 1990), which developed in
response to local soil, fire, and hydrological conditions or resulted from past
anthropogenic causes. All these communities are collectively termed uplands.
Many species of vertebrate and invertebrate animals occur in these botanically rich
communities. Little is known, however, concerning the life history and habitat use
of most of the snakes that reside within upland communities.
The Katharine Ordway Preserve-Swisher Memorial Sanctuary includes a
variety of upland habitats. From 1983 through 1988, RF conducted a general
inventory of resident vertebrates, including snakes. From 1985 through 1990, CKD
monitored the herpetofaunal community inhabiting a temporary pond located
between a longleaf pine and xeric oak hammock (Dodd 1992). As a result of our
efforts, 23 snake species now are known from the Ordway Preserve (Franz this
vol.). The present study was undertaken to provide a more systematic inventory of
the snakes inhabiting upland communities on the Ordway Preserve, and to examine
DODD & FRANZ: UPLAND SNAKES
factors that might influence sampling results. Throughout this paper, we use the
term community as defined by Begon et al. (1986), i.e. "an assemblage of species
populations which occur together in space and time."
ACKNOWLEDGMENTS
We thank Bert Charest, Shelley Franz, and Lora Smith for checking traps, handling snakes, recording
data, and general dedication to the project. Robert Reynolds, Gordon Rodda, and Norm Scott provided
helpful comments on the manuscript
STUDY AREA
The Katharine Ordway Preserve-Swisher Memorial Sanctuary (hereinafter
referred to as the Ordway Preserve) is a 3750 ha tract located approximately 5 km
SE of Melrose, Putnam County, Florida. This upland sandhill region lies within
the Interlachen Karstic Highland at the southern flank of Trail Ridge. The area
represents a portion of a dune complex that probably formed in association with
active beach development during periods of higher sea levels. The dunes have been
secondarily modified by solutioning activities in the underlying limestones to form
sinkholes and karst basins. Many of these solution features hold water to form the
ponds, lakes, and wetlands of the Ordway Preserve. Two types of aquatic systems
occur on the Ordway Preserve, a series of isolated clear water ponds and lakes and
Mill Creek. Mill Creek is an extensive creek system that drains the eastern parts of
Trail Ridge and the Interlachen Karstic Highlands. It flows through Etonia and
Rice creeks into the St. Johns River. On the Ordway Preserve, the basin includes
an extensive swamp forest, eight tannin-stained lakes, and four freshwater
marshes. Franz and Hall (1991) provided a detailed discussion of the physical
setting of the Ordway Preserve.
HABITATS
General information and references on Florida communities are in Myers and
Ewel (1990). Franz and Hall (1991) identified eight vegetative communities on the
Ordway Preserve, five of which were sampled during this study. Approximately
66% of the property is composed of upland and ruderal vegetation types, while the
rest consists of open water pond and lakes or wetlands. More than 70 water bodies
existed on the property prior to a severe drought that began in 1985. This number
was reduced to seven at the height of the drought in 1990.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 38 PT. 1(2)
Most communities have been influenced by human disturbance and past fire
histories. Between 15% and 25% of the property is believed to have been cleared
for agriculture and human habitation since 1850. Several of these areas have
regrown through old field succession to xeric sand live oak and mesic hardwood
hammocks. Regular prescribed burning of high pine forests was established in
1983 as a part of the Ordway Preserve's management protocol for the purpose of
reestablishing the native longleaf pine ecosystem and reducing fuel loads.
High Pine Forest.-- Also known as sandhill, this community type is
dominated by longleaf pine (P. palustris), turkey oak (Q. laevis), and wiregrass (A.
stricta). High pine requires frequent fires in order to maintain its open aspect, to
sponsor pine and wiregrass regeneration, and to control invasive weed species.
Located on Candler and Apopka soil types, the community occurs on deep sands
associated with dune ridges.
Sand Live Oak Hammock.-- This community naturally occurs as fringes
around certain wetland types. It also occurs on ruderal sites. Dominated by sand
live oak (Q. geminata) and occasionally by laurel oak (Q. hemisphaerica), sand
live oak hammocks can have dense understories composed of sapling oaks,
blueberries (Vaccinium spp.), myrtle oak (Q. myrtifolia), and other woody plants.
Reindeer lichens (Cladonia spp. and Cladina spp.) and herbaceous species are
more prevalent in open hammocks. Prescribed fires rarely intrude into sand live
oak hammocks because of sparse fuels and higher moisture conditions than
adjacent high pine forest. For purposes of this paper, sand live oak hammocks are
termed open (very little understory) or closed (very dense understory with complex
habitat structure) xeric hammocks.
Mesic Hardwood Hammocks.-- Located on the lower slopes of the Mill
Creek valley, most mesic hardwood hammocks are dominated by mesic species,
particularly sweet gum (Liquidamber styraciflua), pignut hickory (Carya glabra),
wild olive (Osmanthus americanus), water oaks (Q. nigra), and southern magnolia
(Magnolia grandiflora), although more xeric-adapted pines and oaks commonly
occur on some sites. The interior of most mesic hammocks tend to remain open,
except where saw palmettos (Serenoa repens) form dense thickets. Fires rarely
burn into this community, although they historically have invaded the upper Mill
Creek valley as evidenced by fire-scarred slash pines (P. elliotti) in the vicinity of
Mill Creek ford.
Swamp Forest.-- Dominated by red maple (Acer rubrum), sweet bay
(Magnolia virginiana), black gum (Nyssa sylvatica), and dahoon holly (Ilex
cassine), this community type is restricted to the Mill Creek valley bottomland. In
some areas, slash pines and pond cypress (Taxodium ascendens) form important
DODD & FRANZ: UPLAND SNAKES
components. Ericaceous shrubs often are common understory species. Ferns and
sphagnum moss can form an extensive ground cover on wetter sites.
Freshwater Marshes.-- Extensive wet prairies occur in four large solution
depressions associated with the Mill Creek basin. Certain of these marshes are
dominated by semi-woody species, such as swamp loosestrife (Decodon
verticillatus), fetterbushes (Lyonia lucida), Virginia willow (Itea virginica), and
buttonwood (Cephalanthus occidentalis), while others are composed of
maidencane (Panicum hemitomon) and various sedges. Both types of marshes
frequently have small to large localized stands of sawgrass (Cladium jamaicense)
associated with depressions in the peat. Fires probably have played important roles
in these marsh systems in the past, which probably helped to control invasive
woody species. Currently, Ordway Preserve managers are not burning these sites.
METHODS
Xeric Community Sampling
In 1989, 100 individually numbered screen wire mesh double-opening funnel
traps (90 cm long by 18-25 cm diameter; see Fitch 1987) were placed at six upland
sites as follows: 31 traps in closed xeric (sand live oak) hammock (11 at the
Fennell homestead [Ordway Preserve site location 12]; 20 south of Enslow Lake
[Ordway Preserve site location 21]); 59 traps in sandhill (high pine) habitat (9 at
the Fennell homestead; 10 in the vicinity of Polecat Flats [Ordway Preserve site
location 19]; 10 in the vicinity of Dry Pond [Ordway Preserve site location 20]; 30
in the vicinity of Single Shot Pond [Ordway Preserve site location 23]); 10 traps in
open xeric (sand live oak) hammock (all in the vicinity of the McCloud homestead
[Ordway Preserve site location 22]). The locations of the sampling areas are shown
in Figure 1.
In most cases, the traps were set along fallen trees and branches that formed
natural drift fences. At locations 19 and 20, traps were set along drift fences made
of 10 m sections of galvanized metal set in 4-pronged arrays (Campbell and
Christman 1982, fig. 1). The traps were covered with palmetto fronds to prevent
captured animals from overheating in the direct sun and to provide cover. The
traps were checked daily from April 4 through November 17 (23,800 trap nights)
between 0700 and 1200 h.
Trapped snakes were returned to the laboratory. Prior to measurement, they
were cooled for 1-4 h depending on size. The following data were recorded: snout-
vent and tail length (in mm using a ruler), wet mass body weight (in g using a
Pesola spring scale), sex (using standard reptile sex probes to determine the
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
Figure 1. Map showing the locations of the sampling sites on the Katharine Ordway Preserve-Swisher
Memorial Sanctuary. 02 = Breezeway Pond; 12 = Fennell Homestead; 19 = Polecat Flats; 20 = Dry Pond;
21 = Hammock south of Enslow Lake; 22 = McCloud Homestead; 23 = Sandhill northeast of Single Shot
Pond; 31 = Harry Prairie; 32 = Timmons' Creek; 33 = Mill Creek ford. The dots represent xeric sites; the
squares are mesic sites.
presence of hemipenes in males), and whether injuries or unusual scale patterns
were present. Each snake was given a unique identification number by clipping or
branding ventral and subcaudal scales (Lang 1992). Scale clips, injuries, and
unusual scale patterns were drawn on a standardized data form for cross-reference.
Snakes were released the following day in the vicinity of where they were trapped.
In 1990, the same areas were sampled using the same general techniques
except that all sites were not sampled simultaneously. In addition, 30 traps were set
in closed xeric hammock habitat in the vicinity of Breezeway Pond (Ordway
Preserve location site 02, Fig. 1). This protocol resulted in a total sampling period
of 4,490 trap nights. Traps were placed in the exact same position as in 1989. The
dates that the sites were sampled were as follows: Site 02, 5 April-1 June; Site 12,
DODD & FRANZ: UPLAND SNAKES
3 July-1 August; Sites 19 and 20, 2 June-30 June; Sites 21 and 22, 5 September-
27 September; and Site 23, 2 August-31 August.
Mesic Hammock and Swamp Forest Community Sampling
Funnel traps were set along fallen logs and covered with saw palmetto fronds,
similar to the methods described above. Traps were checked daily between 0700
and 1000 h. Snakes captured in funnel traps were handled in the manner described
above except that they were processed at the time of capture without cooling.
Traps were installed on three mesic and wetland sites. Traps at Harry Prairie
(Ordway Preserve site location 31, Fig. 1) sampled the edges of a drying freshwater
marsh. Sampling was discontinued after five days in June 1989 (100 trap nights)
because of frequent trap disturbances by alligators. Traps at Timmons' Creek
(Ordway Preserve site location 32) were set for 34 days in 1989 (June and
September-October) and for 71 days in 1990 (March-August and October) At Mill
Creek ford (Ordway Preserve site location 33), traps were set for 17 days in 1989
(September-October) and for 71 days in 1990 (March-August and October). Total
traps nights in mesic hardwood hammock totalled 10,872. Traps at Timmons'
Creek and Mill Creek ford sampled both mesic hardwood hammock and swamp
forest communities.
Data Analysis
Capture data are reported separately for xeric and mesic sites because of
differences in sampling methods. Analysis of habitat associations and seasonal
abundance concentrated on the data set derived from sampling the high pine and
xeric hammock communities in 1989, because all traps were set and checked daily
throughout the sampling period. We compared the number of individuals trapped
in 1989 and 1990 at the high pine and xeric hammock sites by using data from
identical sampling periods.
We computed the Shannon-Weiner species diversity index using log, (H) and
values for evenness (J) for snakes trapped in high pine, closed xeric hammock,
and mesic hammock (Krebs 1989). H' was not computed for the other habitats
because of small sample size. For all data, we calculated the number of snakes
trapped in each habitat type in relation to sampling effort (with sampling effort
defined as the relative amount of effort expended at each site, referring to the
amount of time sampled, number of traps per site, or a combination thereof); the
number of snakes per funnel trap versus the number of funnel traps, in each habitat
type; and the total number of snakes per individual funnel trap. For the 1989 xeric
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
habitat data, we tabulated the number of individuals trapped during each biweekly
sampling period for the five most commonly trapped species as well as the mean
number of days between captures at each trap for all species combined.
We divided the 1989 xeric sampling season into three general periods: Spring
(biweekly sampling periods 1-4, 4 April-29 May); Summer (periods 5-12, 30 May-
18 September); Autumn (periods 13-17, 19 September-17 November). We
computed Hurlbert's measure of niche overlap (L) (Hurlbert 1978) for the five most
abundant snakes because resource states, i.e. amounts of available habitat and
seasonal activity, varied in abundance during the sampling period (Krebs 1989).
Hurlbert's measure of niche breadth (B) was calculated for the four most abundant
snakes, because it is sensitive to the selectivity of rare resources (Hurlbert 1978;
Krebs 1989). The scarlet snake (Cemophora coccinea) was excluded, because it
was not trapped in open xeric hammock.
A sufficient sample size was available to compare snout-vent lengths of black
racers (Coluber constrictor) among xeric habitat types to determine if size-related
habitat partitioning occurred. The data on snout-vent lengths in different habitats
first were tested for normality. Inasmuch as the data were not normally distributed,
comparisons were made using the nonparametric procedure NPARIWAY which
corresponds to a Kruskal-Wallis test (SAS Institute, Inc. 1988).
The effects of monthly rainfall and monthly maximum, minimum, and
average temperatures on the total number of snakes trapped were examined using
Spearman Rank Correlation. Statistical analyses were performed using the SAS
program for microcomputers (SAS Institute, Inc. 1988), ABSTAT version 4
(Anderson Bell 1987), and ecological programs in Krebs (1988). The level of
significance was set at a. = 0.05.
RESULTS
Habitat Associations
We captured 10 snake species (234 individuals plus 48 recaptures) in xeric
habitats (Fig. 2) and 11 species (42 individuals plus 5 recaptures) in mesic habitats
(Fig. 3). A few snakes were captured by hand (7) while checking traps and data
from these snakes are included in the results that follow, where appropriate. Most
recaptures occurred within a few days at the same or a nearby trap. The most
commonly trapped snake in both habitat types was the black racer. The next most
commonly captured species were trapped primarily in the xeric habitats, including
the coachwhip (Masticophis flagellum), coral snake (Micrurus fulvius), and the
pygmy rattlesnake (Sistrurus miliarius). Small snake species known from the
Ordway Preserve (Diadophis punctatus, Opheodrys aestivus, Regina alleni,
Seminatrix pygaea, Tantilla relicta) (Franz this vol.) were never trapped.
DODD & FRANZ: UPLAND SNAKES
160- 148 28,290 Trap Nights
140-
120-
100
S 100-
80-
z
60-
40 36
40 -
27
20 14
10 1 2 2
Cad Cco Ccp Egu Hpl Mfl Mfu Pmm Smi Tsi Traps
Species
SSandhill ] Open XH Closed XH
Figure 2. Snakes caught in traps by habitat type in xeric habitats. Cad = Crotalus adamanteus; Cco=
Cemophora coccinea; Ccp = Coluber constrictor, Egu = Elaphe guttata; Hpl = Heterodon platyrhinos;
Mfl = Masticophis flagellum; Mfu = Micrurus fulvius; Pmm = Pituophis melanoleucus; Smi = Sistrrurs
miliarius; Tsi = Thamnophis sirtalis. "Traps" refers to the percentage of trap effort in each habitat type.
The high pine snake community was more diverse (H' = 2.31) and evenly
distributed (J' = .729) than the closed xeric hammock community (H' = 1.49; J' =
.531). Mesic hammocks were intermediate in diversity and evenness (H'= 2.02 and
J' = .639). Within the xeric habitats, most species were found in more than one
habitat type, and those species found in only one habitat type were rarely trapped.
In contrast, the mesic hammock accounted for the vast majority of captures in
mesic habitats although trap sampling bias probably accounts for the lack of
representation of more species in other mesic habitats. Habitat niche overlap values
for the five most common species trapped in xeric habitats are in Table 1 and niche
breadth values are in Table 2.
Snakes trapped in both xeric and mesic communities included juveniles and
large adults (Table 3). However, black racers appeared to be larger in more
structured habitats than in open habitats. Mean SVLs in high pine were smaller
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
Table 1. Niche overlap values for season (upper triangular matrix) and habitat (lower triangular matrix) in
the five most abundant snakes trapped in the uplands of the Katharine Ordway Preserve-Swisher Memorial
Sanctuary, Putnam County, Florida.
Species
Cemophora Coluber Masticophis Micrurus Sistrurus
Species coccinea constrictor flagellum fulvius miliarius
Cemophora coccinea 1.153 1.069 1.242 0.897
Coluber constrictor 0.934 1.152 1.197 0.849
Masticophisflagellum 1.300 0.918 1.153 0.861
Micrurusfulvius 0.695 1.096 0.762 0.838
Sistrurus miliarius 1.364 0.856 1.306 0.669 -
10,872 Trap Nights
30
25
25
-0
E 20
Z
15
10
54
5 1 .3 1 1 1 1 1
CcoCcpEgu Eob Fab Mfl Mfu Nfa Nta Smi TsiTraps
Species
SMesic Hammock 0 Swamp Forest 7 Prairie
Figure 3. Snakes caught in traps by habitat type in mesic habitats. Cco = Cemophora coccinea; Ccp =
Coluber constrictor, Egu = Elaphe guttata; Eob = E. obsoleta; Fab = Farancia abacura; Mfl =
Masticophis flagellum; Mfu = Micrurusfulvius; Nfa = Nerodiafasciata; Nta = N. taxispilota; Smi =
Sistrurus miliarius; Tsi = Thamnophis sirtalis. "Traps" refers to the relative percentage of trap effort in
each habitat type.
DODD & FRANZ: UPLAND SNAKES
Table 2. Niche breadth for four most abundant snakes trapped in uplands on the Katharine Ordway Preserve-
Swisher Memorial Sanctuary, Putnam County, Florida.
Species
Coluber Masticophis Micrurus Sistrurus
Parameter constrictor flagellum fulvius miliarius
Habitat 0.934 0.795 0.775 0.657
Season 0.804 0.829 0.742 0.844
(556.6 mm, N=61) than in open xeric hammock (665.9 mm, N=31) and closed
xeric hammock (686.7 mm, N=19). The difference among means is significant
(X2=16.84, df-2, p=0.0002). The mean SVL of Coluber in mesic habitats was
752.4 mm (N=25).
Seasonal Abundance
With the exception of Cemophora, at least one specimen of the five most
common species was caught each month of the study. In 1989, the majority of C.
constrictor was trapped during the first 12 weeks of the survey (i.e. from early
April through mid-June) with later peaks in late August to early September and
again in late October (Fig. 4). Micrurus fulvius were trapped most often in early
May, but capture sharply dropped thereafter, whereas S. miliarius were trapped
throughout the sampling period with a slight peak in the early autumn. No general
patterns of seasonal capture are apparent for the other two most commonly trapped
xeric habitat species. Cemophora coccinea was trapped only during the warmer
months (Fig. 4), and Masticophis flagellum was trapped at low levels nearly
throughout the sampling period. When temporal sampling periods were matched,
more individuals were caught in 1990 than in 1989 for four of the five most
commonly trapped species (Fig. 5). Seasonal values for niche overlap are in Table
1 and niche breadth in Table 2.
Inasmuch as all traps were not open simultaneously throughout the potential
snake activity period in mesic habitats, it is not possible to determine seasonal
activity patterns unless sampling effort is considered. Figure 6 shows total monthly
snake capture in mesic habitats in relation to sampling effort during that month. A
peak of snake activity is apparent in March. From April to August, the number of
snakes trapped was proportional to sampling effort. In September and October, trap
Table 3. Descriptive statistics for snakes trapped in uplands and mesic habitats on the Katharine Ordway Preserve-Swisher Memorial Sanctuary, Putnam Co.,
Florida, in 1989 and 1990. Snout-vent lengths in mm; wet mass body weight in g. SD = standard deviation.
Snout-vent Length Body Weight
Species N Mean Range SD N Mean Range SD
Uplands Habitats
Cemophora coccinea 10 304.8 (210-364) 46.7 10 9.2 (3.4-14) 3.4
Coluber constrictor 111 609.4 (230-875) 145.2 110 71.4 (3.1-181) 40.3
Crotalus adamanteus 1 457.0 1 56.0
Elaphe guttata 7 548.1 (360-772) 155.6 7 57.1 (14.5-120) 43.2
Heterodon platyrhinos 1 375.0 1 70.0
Masticophisflagellum 37 939.7 (356-1415) 273.1 36 176.8 (8.5-580) 122.2
Micrurusfulvius 33 552.4 (392-715) 65.2 31 31.5 (15-62) 10.9
Pituophis melanoleucus 2 1320 (1300-1340) 28.3 2 770.0 (680-860) 127.3
Sistrurus miliarius 26 339.7 (156-449) 56.6 26 30.0 (5-60) 12.8
Thamnophis sirtalis 2 404.0 (362-446) 59.4 2 24.5 (19-30) 7.8
Mesic Habitats
Coluber constrictor 25 752.3 (412-884) 118.6 25 140.0 (16-241) 53.9
Elapheguttata 2 480.5 (368-593) 159.1 2 31.8 (12-52) 27.9
E. obsoleta 3 553.3 (220-980) 553.3 3 135.1 (18-207) 102.0
Farancia abacura 1 688.0 1 111.8
Masticophisflagellum 2 730.0 (260-1200) 664.7 2 162.7 (6-319) 221.4
Nerodiafasciata 1 350.0 1 57.0
N. taxispilota 1 370.0 1 37.6
Thamnophis sirtalis 1 518.0 1 52.0
DODD & FRANZ: UPLAND SNAKES
Cemophora coccinea
4
1 3 5 7 9 11 13 15 17
BIWEEKLY PERIODS
Masticophis flagellum
a
3 6 7 9 11 13 16 17
BIWEEKLY PERIODS
Coluber constrictor
14
A
1 3 s 7 a 11 1a 16 17
BIWEEKLY PERIODS
Micrurus fuAlius
10. ---
1 '2. \I *M
12
I 1 5 11 1. 16 17
BIWEEKLY PERIODS
Sistrurms miliarius
Figure 4. Biweekly seasonal activity of the five most common species trapped in xeric habitats in 1989.
Cco = Cemophora coccinea; Ccp = Coluber constrictor, Mfl = Masticophis flagellum; Mfu = Micrurus
fulvius; Smi = Sistrurus miliarius. Trapping extended from April 4 to November 17.
effort far exceeded the number of snakes caught, indicating a decline in seasonal
snake activity. Coluber constrictor was the most commonly trapped snake in mesic
habitats, and captures of this species accounted for the large number of snakes
trapped in March. Secondary peaks in number of snakes trapped also occurred in
June and July in mesic hammocks, because many Coluber were trapped, but it is
impossible to separate trap effort from capture effort because of the temporal
sampling protocol in mesic habitats. As with capture in xeric habitats, other
species showed no trends in seasonal activity.
BIWEEKLY PERIODS
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
20
[ 1989
0 [ 1990
LU
Z 15
Q-
rC
" 10
2
5
0N
Cco Ccp Mfl Mfu Smi
SPECIES
Figure 5. Comparison of trap results during identical sampling periods in xeric habitats in 1989 and 1990.
Cco = Cemophora coccinea; Ccp = Coluber constrictor, Mfl = Masticophis flagellum; Mfu = Micrurus
fulvius; Smi = Sistrurus miliarius.
14 20
12
o 15 0)
10 3
0t
110 m
MON)
6 0
E
z
5
2
0 0
Mar Apr May Jun Jul Aug Sep Oct
MONTH
SSnakes M Sampling Effort (%)
Figure 6. Monthly capture of snakes trapped in mesic habitats in 1989 and 1990 in relation to sampling
effort.
DODD & FRANZ: UPLAND SNAKES
711111
.... .... . I _lll l l I . . 11 1 I J I I. I
20 30 40 50 60 70
TRAP NUMBER
80 90 100
5
u 4
I--
uI
m2
O 2
z
1
0
0
N = 60
40 60 1 I00 120
40 60 80 1 00 120
TRAP NUMBER
Figure 7. Total number of snakes captured by individual traps in xeric habitats. (A) 1989; (B) 1990.
Sampling Considerations
Throughout the long 1989 sampling period in xeric habitats, snakes were
caught at least once in 88% of all traps, but only 5% of the traps accounted for six
or more snakes (Fig. 7A). Snakes were caught in only 33.1% of traps in xeric
10r
N= 215
0 10
I III
__
..........
n
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
habitats during the abbreviated sampling period in 1990, and only 2.3% of the
traps caught three or more snakes (Fig. 7B). In mesic habitats, only 25.3% of traps
captured one or more snakes during the 2-year sampling period, and only 1.2% of
traps caught three or more snakes (Fig. 8).
We further examined the effectiveness of certain traps to catch snakes by
calculating the mean number of days between captures, regardless of species
trapped, and plotting this mean against the number of capture intervals (Fig. 9). As
might be expected, increasing the number of intervals between captures resulted in
a decrease in the mean number of days between captures. However, little variation
exists in the mean of the mean number of days between captures when the capture
interval was below four (1 interval mean = 81.9 days; 2 intervals mean = 92.6
days; 3 intervals mean = 97.0 days; 4 intervals mean = 90.8 days).
Habitat appeared to have little effect on the number of snakes caught per
funnel trap. In 1989, most traps in xeric habitats caught one to three snakes,
although the total number of snakes captured per funnel trap in open xeric habitat
was rather uniform (Fig. 10). The number of snakes captured per funnel trap in
1989 is not different from a Poisson distribution both in high pine (X2=3.11, df=4)
and closed xeric hammock (X2=2.87, df=3). Generally fewer snakes were captured
per funnel trap during the abbreviated sampling period in 1990 xeric habitats and
in the mesic habitats in both years. A high percentage of traps captured zero snakes
regardless of habitat type (Figs. 11 and 12).
The average monthly temperatures were similar among years with the
exception of April and May 1990 which were cooler than 1989 (Fig. 13). North-
central Florida experienced a severe drought throughout the study (Dodd 1992
1993). Total rainfall amounts varied considerably among years; 1990 was dryer
than 1989 (Fig. 13). The total number of snakes trapped per month was not
correlated with rainfall (r. = 0.245, p > 0.05), average monthly temperature (r, =
0.248, p > 0.05), maximum monthly temperature (r, = 0.431, p > 0.05), or
minimum monthly temperature (r, = 0.219, p > 0.05).
DISCUSSION
Species Richness and General Habitat Use.- The xeric and mesic habitats
on the Ordway Preserve appear to have similar snake species richness, at least on a
macrohabitat level. Sampling was conducted on a relatively coarse scale, i.e. no
trapping was undertaken in specialized habitats such as fossorial or arboreal
locations within the xeric and mesic habitats. No new records were obtained for the
Preserve, and our subjective impressions of the relative abundance of some species
were substantiated. The Ordway Preserve has similar species richness with
DODD & FRANZ: UPLAND SNAKES
1989 N = 11
1990 N = 42
0O i ie II 1I 1 III I il I In II a II I 1 ai I 1
301 320 340 486 557 611 801 823 941
TRAP NUMBER
Figure 8. Total number of snakes captured by individual traps in mesic habitats, 1989-1990. The dark bars
at the top of the graph show which traps were open in 1989 (top) and 1990 (bottom). N refers to the total
number of snakes captured.
8
21 * . . . *
z
1 *... * *
2
0 50 100 150 200 250
MEAN NUMBER OF DAYS BETWEEN RECAPTURE
Figure 9. The relationship between the number of intervals between snake captures at a trap and the mean
number of days between capture.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
20
Co
S16
Z
u-
12
Lu
0 0
LU
4
z
2
0
Lo
Lu3
z
02
en
02
0 1 2 3 4 5 6 7 8 9
SNAKES PER FUNNEL
0 1 2 3 4
6 7 8 9
6 7 8 9
SNAKES PER FUNNEL
Figure 10. The relationship between the number of traps and the total number of snakes captured per trap in
different xeric habitats in 1989. (A) Sandhills; (B) Closed xeric hammock; (C) Open xeric hammock.
SNAKES PER FUNNEL
DODD & FRANZ: UPLAND SNAKES
40 A
)I
u 30
Z
LL
LL
O 20!
cr
m
Zi 1
0 1 2 0 1 0 1 0 1 2 3 4
SNAKES PER FUNNEL
Figure 11. The relationship between the number of traps and the total number of snakes captured per trap in
different xeric habitats in 1990. (A) Sandhills; (B) Closed xeric hammock; (C) Open xeric hammock; (D).
Sample site surrounding Breezeway Pond.
80 U 1989
Co) M M 1990
A
0 1
0 1
0 1 2 3 4
SNAKES PER FUNNEL
Figure 12. The relationship between the number of traps and the total number of snakes captured per trap in
different mesic habitats in 1989 and 1990. (A) Prairie; (B) Swamp Forest; (C) Mesic hammock.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
Apr 89
May 89
Jun 89
Jul 89
Aug 89
Sep 89
Oct 89
Nov 89
Mar 90
Apr 90
May 90
Jun 90
Jul 90
Aug 90
Cn Qan
-I
I
up II I I
30 25 20 15 10 5 0 5 10 15 20 25 30
Temperature (C) Rainfall (cm)
Figure 13. Average monthly temperature and total rainfall amounts on the Katharine Ordway Preserve-
Swisher Memorial Sanctuary during the 1989 and 1990 sampling period.
comparable sized habitats at the same latitude (Vitt 1987). However, sampling in
other habitat types, particularly the wetlands, may increase the number of species
known to occur on the Preserve.
The black racer was trapped in substantial numbers in all habitat types.
Relatively more black racers were found in mesic hammocks than in xeric habitats,
especially considering differences in sampling effort, but whether this reflects
habitat selection by different size classes or a response to different prey abundance
(Toft 1985; Vitt 1987) is unknown. In xeric habitats, racers were nearly equally
abundant in both high pine and in closed xeric hammock. In all habitats, capture
frequency was proportional to sampling effort. The ubiquitous distribution and
general abundance of Coluber suggests that it is an upland habitat generalist.
The next four most commonly trapped species (Cemophora coccinea,
Masticophis flagellum, Micrurus fulvius, Sistrurus miliarius) were found both in
xeric and mesic habitats, but the numbers trapped seemed to indicate a preference
for the dryer habitats. A narrowing in habitat preference from that shown by C.
constrictor is reflected by the lower niche breadth values for these species. With
the exception ofS. miliarius, considerable niche overlap occurs. In upland habitats,
the pygmy rattlesnake was the most xerophilic of the common snakes trapped
F~z - mmi"
~
-
-
DODD & FRANZ: UPLAND SNAKES
during this study although in other areas they are common in wetlands (e.g.
Hudnall 1979).
The rest of the snakes trapped during the study were caught infrequently.
Based on other observations (see below), several of them (e.g. Crotalus
adamanteus, Pituophis melanoleucus) are known to be common on the Ordway
Preserve (Timmerman 1989; CKD and RF unpubl. data). Others are wetland-
associated species. Only Heterodon platyrhinos appears to be rare on the Ordway
Preserve and was trapped infrequently. Additional sampling, using a variety of
techniques in more habitat types, will be necessary before the habitat associations
of these species on the Ordway Preserve can be discerned.
We suggest that a possible explanation of the similarity of the upland snake
faunas in different habitat types on the Ordway Preserve is that they share a similar
derivation. Approximately 47 percent of the uplands presently are in high pine
vegetation. Xeric hammocks are found surrounding the numerous lakes in formerly
cultivated areas on the property and in the Mill Creek valley. Examination of aerial
photographs taken more than 30 years ago and conversations with elderly residents
familiar with the land confirm that most xeric hammocks were cleared for
agriculture or homesteads at one time, usually 50 to 70 years ago. These hammocks
probably were in high pine vegetation prior to cultivation. Thus, the xeric
hammocks are of relatively recent origin and do not contain species, such as
Storeria occipitomaculata, found in historically undisturbed hammocks.
Seasonal Activity Patterns.- The five most commonly trapped species did
not show similar seasonal activity patterns, and the activity patterns (Fig. 4) often
were different from literature records. For example, Coluber constrictor is reported
to have a bimodal seasonal activity period in Nebraska, based on road kills (Oliver
1955), and a unimodal activity period centered on the late spring to early summer
in South Carolina (Gibbons and Semlitsch 1987) and southern Florida (Dalrymple
et al. 1991b). Micrurus is active year-round in Florida with a bimodal activity
season in spring and autumn (Jackson and Franz 1981; Dalrymple et al. 1991b).
Our observations are similar to literature records for Sistrurus (Hudnall 1979;
Dalrymple et al. 1991b), Masticophis (Ford et al. 1991), and Cemophora (Reynolds
1980; Gibbons and Semlitsch 1987; Dalrymple et al. 1991b).
The four most trapped species were active throughout the sampling period, as
reflected in niche breadth values. Micrurus overlapped seasonally least with the
other species, whereas the warm weather xeric habitat species Cemophora,
Masticophis, and Sistrurus had the greatest seasonal niche overlap. The spring
activity peak in Coluber and the autumn increase in Sistrurus are reflected in their
medial niche overlap values. In general, there does not appear to be much seasonal
partitioning of activity, perhaps because of the generally long activity seasons of
most species.
Gibbons and Semlitsch (1987) suggested that Temperate Zone snakes showed
two general activity patterns, a unimodal pattern centered on warm weather
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
activity and a bimodal pattern centered on spring and autumn activity peaks. On
the Ordway Preserve, such patterns were observed, but the patterns were more
complex with less adherence to a particular modality. Failure to conform to
recognized patterns suggests that sampling may be biased, that 1989 may have
been an unusual year in terms of snake activity, that concepts of modality in
subtropical snake activity patterns need to be refined to incorporate the possibility
of both variation and complex patterns, or that all of these factors may be true. In
areas with year-round activity, snakes seem to keep the general patterns observed
in more northern latitude relatives but retain the plasticity to modify activity in
accordance with local environmental conditions (Dalrymple et al. 1991b).
Sampling considerations.-Funnel traps have been used successfully to obtain
data on both individual snake species and communities (Fitch 1960 1987; Ford et
al. 1991). Clearly, the technique is effective at capturing certain upland species,
such as Coluber, Micrurus, and Sistrurus. Six or more snakes were captured in
only five traps throughout the study, providing little evidence of biased trapping.
Although more traps had zero capture success in xeric habitats in 1990 than in
1989, the sampling effort was only 16% of that in 1989. Likewise, many mesic
habitat traps had zero capture success during the two-year study, but mesic habitats
were sampled for only 28% of the sampling total. Snakes did not shy away from
any cluster of traps in any habitat type.
On the other hand, why did most traps capture few snakes? Several
hypotheses are possible, including insufficient sampling effort, generally poor trap
placement, low snake density, or escape from traps before the observer checked
them. Snakes also may avoid traps in which other snakes had been caught, perhaps
due to chemoreceptive cues left by previous occupants (but see Weldon et al. 1990).
None of these hypotheses can be ruled out, and all may affect capture success.
The 14 species of snakes trapped during the study represent 61 percent of the
snakes known from the Ordway Preserve (Franz this vol.). Other snake species
(Diadophis punctatus, Drymarchon corals, and Tantilla relicta) are known from
upland habitats on the Ordway Preserve but were not trapped. In addition, general
collecting, radio-telemetry studies, and subjective impressions suggest that
additional species, such as Crotalus adamanteus (Timmerman 1989), Elaphe
guttata, E. obsoleta, and Pituophis melanoleucus, were underrepresented in funnel
traps in relation to their probable abundance. Such discrepancies suggest that
funnel trapping alone is inadequate to sample all species of an upland snake
community.
Snake size, habitat specificity, and foraging mode may play an important role
in the effectiveness of funnel traps to sample communities. Those upland species
either not trapped or underrepresented were generally small as adults (Diadophis,
Tantilla) or very large and robust as adults (Crotalus, Drymarchon, Pituophis). On
the other hand, small robust Sistrurus and large slender Masticophis were trapped.
Habitat specificity, such as fossorial (Tantilla) or arboreal (E. guttata, Opheodrys)
DODD & FRANZ: UPLAND SNAKES
habitat preferences, may restrict the effectiveness of funnel trap sampling. Ford et
al. (1991) also were unable to capture Tantilla in funnel traps.
Several species that were trapped, such as Nerodia fasciata and N.
taxispilota, are aquatic species and as such were unexpected in xeric upland
habitats. However, Dodd (1992) found some non-resident aquatic or wetland-
associated species that regularly visited a small isolated temporary pond located in
upland habitat on the Ordway Preserve. Snakes normally associated with wetland
habitats may travel across unfavorable habitat to find foraging areas or to disperse
during unfavorable environmental conditions (Dodd 1993; Seigel et al. ms). On the
Ordway Preserve, six additional wetland-associated species (Farancia abacura,
Nerodia floridana, Opheodrys aestivus, Regina alleni, Seminatrix pygaea,
Thamnophis sauritus) are known to at least occasionally cross upland habitat
(Dodd 1992; unpubl. observe ) but were not trapped during the study. The likelihood
of trapping wetland-associated species as they move across upland habitat would
seem to be small, unless the uplands were located adjacent to wetlands subject to
periodic desiccation. In such locations, seasonal snake activity is influenced by
fluctuations in the water table resulting in increased capture as wetlands dry
(Bernardino and Dalrymple 1992).
Finally, active foragers, such as Masticophis and Coluber, should be more
likely to encounter funnel traps than sit-and-wait predators such as Crotalus.
Active foragers, especially those that take a wide range of prey, also are more likely
than sit-and-wait predators to be drawn to traps through intra- or interspecific
chemical cues or the activity of prey species (lizards, other snakes, or rodents)
caught in the traps.
Based on our results and those of other recent investigators (Fitch 1992;
Grant et al. 1992; Rodda and Fritts 1992), we suggest that funnel traps should not
be employed as the sole method for community sampling. All sampling techniques
have biases and limitations, but certain questions, such as those involving the
determination of activity patterns, often can be addressed using a non-trap biased
approach (Reynolds 1982; Price and LaPointe 1990; Dalrymple et al. 1991a;
Dalrymple et al. 1991b; Bernardino and Dalrymple 1992). Inventory sampling
should use a variety of techniques, such as pitfall traps with drift fences (Gibbons
and Semlitsch 1982), road-cruising (Klauber 1939), coverboards (Grant et al.
1992), and time-constraint sampling (Campbell and Christman 1982), to
supplement funnel trap data (Fitch 1992).
LITERATURE CITED
Anderson Bell. 1987. ABSTAT. Release 4. Parker, Colorado.
Begon, M., J. L Harper, and C. R. Townsend. 1986. Ecology: Individuals, populations and communities.
Blackwell, Oxford.
Bernardino, F. S., Jr., and G. H. Dalrymple. 1992. Seasonal activity and road mortality of the snakes of the
Pa-hay-okee wetlands of Everglades National Park, USA. Biol. Conserve. 62:71-75.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2)
Campbell, H. W. and S. P. Christman. 1982. Field techniques for herpetofaunal community analysis. Pp.
193-200 in N. J. Scott, Jr., ed. Herpetological communities. U.S. Fish Wildl. Serv., Wildl. Res. Rept.
13.
Croker, T. C. 1979. The longleaf pine story. J. For. Hist Jan:32-43.
Dalrymple, G. H., F. S. Bernardino, Jr., T. M. Steiner, and R. J. Nodell. 1991a. Patterns of species diversity
of snake community assemblages, with data on two Everglades snake assemblages. Copeia
1991:517-521.
Dalrymple, G. H., T. M. Steiner, R. J. Nodell, and F. S. Bemardino, Jr. 1991b. Seasonal activity of the
snakes of Long Pine Key, Everglades National Park. Copeia 1991:294-302.
Dodd, C. K., Jr. 1992. Biological diversity of a temporary pond herpetofauna in north Florida sandhills.
Biodiver. Conserv. 1:125-142.
1993. Population structure, body mass, activity, and orientation of an aquatic snake (Seminatrix
pygaea) during a drought Canadian J. Zool. 71:1281-1288.
Fitch, H. S. 1960. Autecology of the copperhead. Univ. Kansas Publ. Mus. Nat. Hist 13:85-288.
1987. Collecting and life-history techniques. Pp. 143-164 in R. A Seigel, J. T. Collins, and S. S.
Novak, eds. Snakes. Ecology and evolutionary biology. MacMillan and Co., New York.
1992. Methods of sampling snake populations and their relative success. Herp. Rev. 23:17-19.
Ford, N. B., V. A. Cobb and J. Stout 1991. Species diversity and seasonal abundance of snakes in a mixed
pine-hardwood forest of eastern Texas. Southwest. Nat 36:171-177.
and D. W. Hall. 1991. Vegetative communities and annotated plant lists for the Katharine Ordway
Preserve-Swisher Memorial Sanctuary, Putnam County, Florida. Ordway Preserve Res. Ser., Rept.
3:1-65.
Gibbons, J. W., and R. D. Semlitsch. 1982. Terrestrial drift fences with pitfall traps: An effective technique
for quantitative sampling of animal populations. Brimleyana 7:1-16.
__ and 1987. Activity patterns. Pp. 396-421 in R. A. Seigel, J. T. Collins, and S. S. Novak,
eds. Snakes. Ecology and evolutionary biology. MacMillan and Co., New York.
Grant, B. W., A. D. Tucker, J. E. Lovich, A. M. Mills, P. M. Dixon, and J. W. Gibbons. 1992. The use of
coverboards in estimating patterns of reptile and amphibian biodiversity. Pp. 379-403 in D. R.
McCullough and R. H. Barrett, eds. Wildlife 2001: Populations. Elsevier Applied Science, London.
Hudnall, J. A. 1979. Surface activity and horizontal movements in a marked population of Sistrurus
miliarius barbouri. Bull. Maryland Herp. Soc. 15:134-138.
Hurlbert, S. H. 1978. The measurement of niche overlap and some relatives. Ecology 59:67-77.
Jackson, D. R., and R. Franz. 1981. Ecology of the eastern coral snake (Micrurusfulvius) in northern
peninsular Florida. Herpetologica 37:213-228.
Klauber, L. M. 1939. Studies of reptile life in the arid southwest. Part 1. Night collecting on the desert
with ecological statistics. Bull. Zool. Soc. San Diego 14:7-64.
Krebs, C. J. 1988. Fortran programs for Ecological Methodology. Univ. British Columbia, Vancouver
(Canada).
1989. Ecological Methodology. Harper & Row Publishing Co., New York.
Lang, M. 1992. A review of techniques for marking snakes. Smithsonian Herp. Inform. Serv. 90:1-19.
Means, D. B., and G. Grow. 1985. The endangered long-leaf pine community. ENFO (Florida
Conservation Foundation) Sept: 1-12.
Myers, R. L 1990. Scrub and high pine. Pp. 150-193 in R. L. Myers and J. J. Ewel, eds. Ecosystems of
Florida. Univ. C. Florida Press, Orlando.
and J. J. Ewel. 1990. Ecosystems of Florida. Univ. C. Florida Press, Orlando.
Noss, R. F. 1989. Longleaf pine and wiregrass: Keystone components of an endangered ecosystem. Nat.
Areas J. 9:211-213.
Oliver, J. A. 1955 The natural history of North American amphibians and reptiles. Van Nostrand Co.,
Princeton, New Jersey.
Price, A. H., and J. L. LaPointe. 1990. Activity patterns of a Chihuahuan Desert snake community. Ann.
Carnegie Mus. 59:15-23.
Reynolds, J. P. 1980. A mark-recapture study of the scarlet snake, Cemophora coccinea, in a coastal plain
sandhill community. M.S. Thesis, North Carolina State Univ., Raleigh.
Reynolds, R. P. 1982. Seasonal incidence of snakes in northeastern Chihuahua, Mexico. Southwest. Nat.
27:161-166.
Rodda, G. H., and T. H. Fritts. 1992. Sampling techniques for an arboreal snake, Boiga irregularis.
Micronesica 25:23-40.
DODD & FRANZ: UPLAND SNAKES 67
SAS Institute Inc. 1988. SAS/STAT user's guide. Release 6.03 edition. SAS Institute Inc., Cary, North
Carolina.
Timmerman, W. W. 1989. Home range, habitat use and behavior of the eastern diamondback rattlesnake.
M.S. Thesis, Univ. Florida, Gainesville.
Toft, C. A. 1985. Resource partitioning in amphibians and reptiles. Copeia 1985:1-21.
Vitt, L. J. 1987. Communities. Pp. 335-365 in R. A. Seigel, J. T. Collins, and S. S. Novak, eds. Snakes.
Ecology and evolutionary biology. MacMillan and Co., New York.
Weldon, P. J., N. B. Ford, and J. J. Perry-Richardson. 1990. Responses by corn snakes (Elaphe guttata) to
chemicals from heterospecific snakes. J. Chem. Ecol. 16:37-44.
VEGETATION OF SELECTED UPLAND TEMPORARY
PONDS IN NORTH AND NORTH-CENTRAL FLORIDA
Linda V. LaClaire'
ABSTRACT
Vegetation was sampled in 13 temporary ponds located in uplands of north and north-central Florida.
The ponds were selected for study because they represented potential breeding sites for 2 rare amphibians,
the gopher frog, Rana capitol aesopus, and the striped newt, Notophthalmus perstriatus. Vegetation in the
non-forested depression ponds was analyzed in order to determine if a set of characteristic species was
present in each. These date then could be used to identify breeding sites for the two species and to provide
information for use in the development of management plans for the sites. The study ponds generally fill
during winter rains and completely dry down during the summer, but, during the period of this research,
Florida was experiencing a relatively dry period, and some ponds did not fill on an annual basis.
A total of 112 vascular plant species were identified in the pond basins. Panicum hemitomon was the
only species present at each pond. Other common species included Andropogon glomeratus, Rhexia
mariana var. mariana, Eupatorium leptophyllum, Rhynchospora spp., Ilex glabra, Cephalanthus
occidentalis, and members of the family Eriocaulaceae. Similarities between ponds generally resulted from
similarities in hydrologic cycle, defined as the period of time since each had held water, and the proximity of
ponds to each other. The vegetation of each pond reflected a pattern of zonation or banding commonly
described for temporary ponds in other regions. Wetland index values calculated for each pond fit wetland
designation criteria, including a basin that had not formed a pond for 7 years, Dry Pond. Species richness
and diversity were highest in ponds that had recently dried down and lowest in flooded ponds and Dry Pond.
RESUME
Se muestre6 la vegetaci6n de 13 estanques temporaries en las tierras altas del norte y norte-centro de
Florida. Se seleccionaron los estanques que representaban potenciales sitios reproductivos de dos species
raras de anfibios, el sapo excavador de Florida, Rana capitol aesopus, y la salamandra rayada,
Notophthalmus perstriatus. Estos estanques, que ocupan bajos en areas no forestadas, se ajustan a un patr6n
general de Ilenado durante las Iluvias de inviero y de complete vaciamiento durante el verano. Florida
1
The author is a Wildlife Biologist of Herpetology and Avian Ecology at the U. S. Fish and Wildlife Service, 6578 Dogwood View
Parkway, Suite A, Jackson MS 39213, USA.
LACLAIRE, L. V. 1995. Vegetation of selected upland temporary ponds in north and north-central Florida.
Bull. Florida Mus. Nat. Hist. 38, Pt. I(3):69-96.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I (3)
experiment un period relativamente seco durante este studio y por lo tanto, algunos estanques no se
Ilenaron anualmente.
Las comunidades vegetacionales se identificaron en base a informaci6n de transectos y bisquedas de
circuitos en las cuencas de los estanques. Con el objeto de determinar sin un numero de species
caracteristicas pudiera ser utilizado para la identificaci6n de sitios de reproducci6n de las dos species de
anfibios, se realizaron anilisis vegetacionales. Se identific6 un total de 112 plants vasculares provenientes
de cuencas en los estanques. Panicum hemitomon fue la inica especie present en cada estanque. Otras
species comunes fueron Andropogon glomeratus, Rhexia mariana var. mariana, Eupatorium
leptophyllum, Rhynchospora spp., Ilex glabra, Cephalanthus occidentalis y miembros de la familiar
Eriocaulaceae. Las semejanzas vegetativas entire estanques, estuvieron por lo general correlacionadas con
similaridades en el ciclo hidrol6gico (el tiempo transcurrido desde que cada estanque tuvo agua) y la
cercania entire estanques. La vegetaci6n en cada estanque reflej6 un patr6n de zonaci6n comunmente descrito
para estanques temporarios en otras regions. Los valores de indices de humedales calculados para cada
estanque cayeron dentro del rango descrito para humedales, incluyendo una cuenca que no form estanque
durante 7 afios. La riqueza y diversidad de species fueron miximas en estanques secados recientemente (< 1
ailo desde inundaci6n) y minimas en estanques inundados y en estanques secos por various afios.
INTRODUCTION
Vegetation data from upland temporary ponds in north and north-central
Florida were collected as part of a larger project to determine the ecology and
distribution of two rare amphibians, the Florida gopher frog, Rana capitol aesopus,
and the striped newt, Notophthalmus perstriatus (LaClaire 1992; Franz and Smith
1993). Temporary ponds are required breeding habitat for these upland-dwelling
amphibians (Moler and Franz 1987). In order to ensure the survival of these two
species, effective management of their breeding habitat is imperative.
An understanding of the temporary pond plant community is essential to the
development of appropriate management plans for these pond basins. The wetland
vegetation of temporary ponds is an important source of available nutrients for
pond-dwelling plants and animals and of humified organic matter that may be
crucial to the ability of a pond to hold water (LaClaire 1992).
It is especially important that management practices do not alter the existing
hydrology of a temporary pond basin. Alteration of the hydrologic regime may
seriously impact the development of hydric soils, structure of the plant community,
and temporal use by amphibians. Both reduction of the water budget and
stabilization of water levels have figured prominently in the ecological decline of
many undrained Florida wetlands (Lowe 1986). For example, use of temporary
ponds as water retention basins stabilizes the water level and may result in
successional changes toward a community dominated by emergent genera such as
Pontederia sp., Typha sp., or Scirpus sp., rather than the grass/sedge community
(Botts and Cowell 1988) required by many species of amphibians for egg
attachment. The high variability and instability of the hydrologic component of
the temporary pond environment results in a community which is highly
susceptible to other disturbance (Gopal 1986).
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
The objective of this study was to provide information on the vegetative
community of upland temporary ponds in north and north-central Florida. Little
information is available on the species composition and distribution in these
wetlands. Plant community structure was investigated with the goal of formulating
some generalizations about the pond habitat which could be used to identify the
type temporary pond used for breeding by the gopher frog and/or the striped newt.
To fulfill the study objective the following questions were asked:
1) What plant species characterize each pond basin?
2) How similar is the vegetation of each site to each other?
3) Does the vegetation reflect a pattern of structure, association, spatial shift,
or zonation?
4) Since considerable attention has been focused on wetland designation
criteria, does the vegetation of each pond correspond to a wetland index
value indicative of wetland?
5) What is the effect of hydrology on species richness, diversity, and
distribution?
ACKNOWLEDGEMENTS
I thank Kenneth S. Clough, Richard (Dick) Franz, C. Kenneth Dodd, Jr., and Lora Smith for field
assistance; Cary Norquist and Sidney McDaniel for plant identification; Robert L. Jones for computer
assistance; and an anonymous reviewer whose comments significantly improved the manuscript. I am
especially grateful to Dick Franz for encouragement and support. This work was undertaken in partial
fulfillment of the requirements for the degree of Master of Science at the University of Florida.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I (3)
TEMPORARY PONDS
Defining a Temporary Pond
Temporary wetlands can be defined as natural bodies of water which experience
a recurrent dry phase of varying duration (Williams 1987). The hydrologic
emphasis in these wetlands is on the cyclic nature of drying and re-filling as
permanent waterbodies are also capable of drying completely in exceptional years.
In addition, selection has occurred in temporary wetlands for species adapted to
this cyclic drying and filling and results in periodic bursts of productivity that fuel
these systems (Patrick and Khalid 1974; Brinson et al. 1981; Reddy and Graetz
1988).
A temporary pond is a small (generally less than 5 hectares), isolated,
temporary wetland that is depressional in nature. There is considerable confusion
of terms in dealing with these small temporary wetlands, both among regulatory
agencies and in the literature. Terms used to describe them include flatwoods
marshes/ponds, ephemeral ponds/wetlands, highlands marshes, pineland
depressions, depression meadows/marshes, St. John's wort ponds, seasonal
marshes/ponds, intermittent ponds, and vernal pools (Holland 1988; Florida
Natural Areas Inventory and Florida Department of Natural Resources 1990;
Kushlan 1990). Some of these terms allude to the fact that temporary ponds are
difficult to identify as wetlands during their dry cycle (Means 1990).
Hydrology
Hydrology is the major factor influencing and maintaining the community of
wetland plants in the temporary pond basin (Mitsch and Gosselink 1986). External
water inputs transport nutrients into the system and mobilize those bound in
vegetation and soil. Water depth, duration, and frequency of flooding all influence
the formation of hydric soils and the presence of hydrophytes within the pond
(Gosselink and Turner 1978). The hydroperiod of temporary ponds is highly
variable, depending upon elevation, basin characteristics, and rainfall patterns
(Means 1990). Some ponds may fill and dry on an annual basis while others may
contain water only in the wettest years.
When a temporary pond drains, productivity is lowered and aerobic
decomposers begin rapidly breaking down the accumulated organic matter (Cole
and Fisher 1979; Reddy et al. 1986). Temporary ponds are detrital systems, and
most of the organic production decomposes before entering the detrital food chain
(Mitsch and Gosselink 1986). The vegetation of the pond basin is readily and
almost completely decomposed on a cyclic basis (Gopal 1986). The breakdown of
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
organic matter facilitates maintenance of a temporary pond rather than a
permanent one.
Life History Strategies of Wetland Plants
Three key life history traits can be used to characterize wetland species (van
der Valk 1981). These are life span, propagule longevity, and propagule
establishment requirements. Propagules may be seeds or vegetative structures, and
a single species may have both modes of reproduction which function under
different hydrologic regimes.
Wetland plants include both annuals and perennials. Annuals may be found on
exposed soil during drawdowns or may occur as submersed or free-floating
aquatics (van der Valk 1981). Due to the ephemeral nature of annuals, perennials
may serve as better wetland indicators. The most prevalent life history strategy
among temporary pond aquatic species is represented by vegetatively reproducing
perennials (van der Valk 1981).
Plant species may be considered drawdown species, standing water species, or
generalists relative to propagule establishment (van der Valk 1981). The majority
of emergent species germinate primarily on exposed areas free of vegetation. They
require exposure to light and/or alternating extremes of temperature. Vegetative
propagule formation may occur in response to drawdown and accompanying
temperature changes (Gopal 1986). Submersed, free-floating, and floating-leaved
species have seeds that require a flooded substrate for germination. There are also
species that can be considered generalists which germinate in both exposed and
inundated conditions (Gerritsen and Greening 1989). Relative species' abundances
fluctuate due to modes of germination and frequency and duration of wet/dry cycles
in the pond basins. Spatial gradients in seed bank density and viability may be
later expressed in spatial patterns of adult populations and can result in patterns of
zonation (Lowe 1986).
Structure of Vegetation in Temporary Ponds
The distribution of water in time and space is the single most important factor
influencing the occurrence of temporary pond macrophytes. Soil moisture is an
important component. Plants in the temporary pond environment demonstrate a
range of adaptations for tolerating inundation. Their distribution may follow
hydrologic patterns and result in a zonation of vegetation in the pond basin
(Laessle 1942; Lippert and Jameson 1964; van der Valk and Davis 1976;
Abrahamson et al. 1984; Bridges and Orzell 1989; Kushlan 1990). Concentric
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(3)
rings of different species and vegetative types can occur in temporary ponds as
band-like divisions related to hydrology and slope (Lippert and Jameson 1964;
Weller 1979). A typical pattern of zonation in a temporary pond has several
discrete components, depending on soil moisture and the extent of flooding in the
basin. The center of a flooded pond often contains floating-leaved plants. This
inner zone is typically surrounded by vegetation with submerged roots growing in
wet edges. Extending out from this zone, in damp ground surrounding the wet
areas, is a band of tall and short emergents, such as sedges, rushes, and grasses.
Other grasses and composites occur in drier margins of the ponds followed lastly
by water-tolerant shrubs or trees in transitional zones (Lippert and Jameson 1964;
Weller 1979; Kushlan 1990; LaClaire and Franz 1991). The bands of vegetation
move back and forth across the pond basin in a reflection of changing soil moisture
conditions (LaClaire and Franz 1991).
The wetland plants occurring in these basins have evolved adaptations to
alternating wet/dry periods and often require this cycle of inundation/drawdown for
their survival (van der Valk 1981). In other words, periodic water level changes,
including periodic drought, are required for maintenance of the temporary pond
plant community. The magnitude and frequency of the water level changes can be
perceived as gradients of a normal environment along which the different wetland
plants are distributed (Gopal 1986).
Basic information on the vegetation of temporary ponds in south and west-
central Florida is available from several studies (Huffman 1982; Abrahamson et al.
1984; Botts and Cowell 1988), but a detailed description of the vegetation of
temporary ponds in north and north-central Florida previously has been lacking.
An overview of freshwater marshes in Florida was written by Kushlan (1990). He
described zones of vegetation, determined by hydroperiod, elevation, and water
depth, as typical of large highland marshes (central ridge of Florida) and flatwoods
marshes (pine flatwoods). The zonation and species composition within these
marshes have similarities to temporary ponds. Species in common with temporary
ponds are described below. Nymphaea sp. Occurred in deep water centers with
Panicum hemitomon on higher ground, intermixed with Leersia hexandra, Juncus
sp., Polygonum sp., and Lachnanthes caroliniana. Farther upslope, Rhynchospora
inundata, R. tracyi (flatwoods marsh), and Eleocharis sp. occurred. The
uppermost zone of the flatwoods marsh, which completely dried-out each year,
supported a wet prairie association with a variable species composition dominated
by Hypericum fasciculatum, Amphicarpum muhlenbergianum, Panicum abscissum,
and Xyris spp.. Flatwoods marsh terminated abruptly in a border of woody
vegetation containing Serenoa repens, Cephalanthus occidentalis, Salix sp.,
Fraxinus sp., Ilex glabra, Lyonia sp., and slash pine (Pinus elliottii), or dry prairie.
Panicum hemitomon marshes dominated the higher ground on sandy substrates
and typically had a Sphagnum mat. Andropogon spp. and Spartina bakeri were
also mentioned as occurring in some marsh associations.
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
The distribution of vegetation within the temporary pond basin results from a
predictable sequence of events summarized below (LaClaire and Franz 1991).
There is a growth flush of aquatic and marsh vegetation following the rainy season.
As the pond basins begin to dry, the above-ground growth of most species
gradually senesces and decomposes, leaving behind only seeds or below-ground
vegetative propagules and roots. Upon completion of pond drying, another
characteristic plant community appears. Species in this assemblage have short
vegetative cycles and generally disappear before ponds refill. As soil moisture
continues to drop, most plants disappear, and only those with fibrous stalks remain.
In some instances, ruderal species may then move into the basins.
Fire can also be an important element in the distribution of wetland vegetation
in temporary ponds. Fire suppression, for example, may result in fire intolerant
species invading the pond basin and altering the plant community structure.
Panicum hemitomon re-sprouts rapidly after fire and, as a result, can develop dense
monotypic stands. Other plants, such as Hypericumfasciculatum, may be killed by
fire, but their seeds are adapted to germinate after the plant has been burned.
MATERIALS AND METHODS
Description of Study Sites
The four sites selected for this study of temporary wetland vegetation were
chosen because they contained breeding ponds for the Florida gopher frog and the
striped newt. These amphibians occur in xeric conditions found in sandhill and
scrub habitats, except during the breeding season, when they move to temporary
ponds embedded within this landscape. Temporary ponds selected for study were
located in north and north-central Florida and were associated with karst
landscapes overlain by acidic, sandy soils. As a result of acids leaching from the
pinelands through these well-drained soils, the limestone has slumped to form
numerous sinkholes and depressions, some of which have developed into
temporary ponds. Thirteen temporary ponds were chosen for study within the
Apalachicola National Forest (ANF) in Leon County, the Katharine Ordway
Preserve-Carl Swisher Memorial Sanctuary (OSMP) and the Welaka Research and
Education Center (WREC) in Putnam County, and the Ocala National Forest
(ONF) located in Marion and Putnam counties. Of the 13 ponds, 9 were known
breeding sites for either the striped newt or the gopher frog (Table 1).
Unfortunately, due to the effects of drought, it could not be determined with
certainty whether or not the remaining four ponds represented breeding sites for
these species. However, the data obtained may be useful at a later date when
amphibian surveys of these sites are completed. Individual pond names,
designations, and basin descriptions are given below.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(3)
Table 1. Dimensions of all temporary pond basins studied. Amphibian breeding codes are: 0-unknown,
S=Notophthalmus perstriatus, 2=Rana capitol, 3=both species.
Breeding Dimensions of Pond Basins
Pond Code N-S E-W
ANF-1 1 50 m 64m
ANF-3 3 83 m 80 m
ANF-4 3 35m 70 m
GP 2 168 m 205 m
BP 3 95m 95m
OS 3 87m 93m
HP 3 105m 100 m
DP 0 78m 69m
WE-5 0 45 m 93 m
WE-6 0 66m 63 m
WE-11 0 82m 96m
LDP 1 105 m 103 m
RP 3 140m 144m
Vegetation of three ponds was sampled in ANF. The ponds were designated as
ANF-1, ANF-3, and ANF-4 and were sampled in May 1990. In OSMP, the
vegetation of five ponds, Gopher Pond (GP), Breezeway Pond (BP), One Shot Pond
(OS), Harry Prairie Pond (HP), and Dry Pond (DP) was sampled in June and July
1990. Breezeway Pond and GP were also sampled in October and November 1989,
and the results of that survey are included (LaClaire and Smith unpubl. MS).
Vegetation of three ponds in WREC was also sampled in July 1990; pond
designations are WE-5, WE-6, and WE-11. Qualitative plant lists were compiled
for Lake Delancy Pond (LDP) in ONF and Recess Pond (RP) located on private
property adjacent to OSMP. Lake Delancy Pond was sampled January 1990 and
June 1991, and RP was sampled every 10 days May through August 1991 as part of
another study (LaClaire unpubl. data).
The size of the pond basins, estimated from north-south and east-west axes
terminating at the pond/upland boundary, ranged from less than a hectare to
approximately 3 hectares (Table 1). These ponds were dominated by grasses,
sedges, and herbaceous vegetation, and none were forested wetlands. All of the
ponds had historical breeding records for either the Florida gopher frog or the
striped newt with the exception of Dry Pond in OSMP and the ponds located in
WREC. Dry Pond was selected because it had been dry for at least seven years
prior to the study and represented an extreme in length of the dry phase of
temporary ponds. The ponds in WREC were thought to represent potential
breeding ponds for the Florida gopher frog. The gopher frog is known to occur in
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
gopher tortoise burrows on site near the ponds (R. Franz pers. comm) but has not
been studied in its breeding habitat.
The history of pond drying and re-filling at each site was obtained from
knowledgeable sources whenever possible. Unfortunately, hydrologic data were
only partially available for the study ponds. The ANF ponds had the longest
known hydroperiod and the OSMP ponds the shortest. Since the hydroperiod of
each pond could not be compared, inferences about hydrology are based on the only
variable known for each pond, months since the pond had held water when it was
sampled.
Apalachicola National Forest.-- The Apalachicola study area is located in a
region called the Lake Munson Hills on the northwestern portion of the Woodville
Karst Plain and in the extreme northeastern corner of the ANF (USDA 1984). The
study ponds, ANF-1, ANF-3, and ANF-4, have formed on depressions located on
well-drained Ortega sands. These ponds are described in an article by Means
(1990). The surrounding forest is composed of native longleaf pine (Pinus
palustris) with some slash (P. elliotti) and loblolly pine (P. taeda) and is managed
for timber production by the USDA Forest Service. A few scattered oaks surround
the pond basins.
Katharine Ordway Preserve-Carl Swisher Memorial Sanctuary.-- The
OSMP is located on the Interlachen Karst Plain at the southern flank of Trail
Ridge in western Putnam County (Franz and Hall 1991). This is an area of
extensive sandhills underlain by well to excessively drained Candler-Apopka soils.
The vegetation surrounding the five OSMP ponds and the adjacent RP consisted of
longleaf pine/turkey oak (Quercus laevis) forests and xeric oak hammocks that are
typical elements of sandhill communities.
From the Soil Survey of Putnam County (Readle 1990), some discrimination of
soil types can be made in the pond basins. Gopher Pond, BP, and HP were mapped
as Placid fine sand, depressional. This soil is in depressional areas on the uplands
and has a high available water capacity in the surface layer. Gopher Pond and BP
are on the outer fringes of lake basins, and under extreme high water, perhaps a
hundred year flood, they would be contiguous with them (USGS map, circa 1935).
Harry Prairie Pond is at the outer edge of a wet prairie system but separated from it
by a low sand ridge. A connection with the prairie would be possible under
extreme high water. Dry Pond was mapped as Ona fine sand, a poorly drained soil
typical of ponded areas. One Shot Pond was the only pond in which the soil of the
pond basin was not specifically described, because it was improperly mapped as a
perennial pond by the Putnam County soil survey (Readle 1990).
Welaka Research and Education Center.-- The WREC lies to the east of the
St. John's River valley on an isolated ridge of Candler-Apopka soils and sandhill
and scrub vegetation (Readle 1990). The study ponds, WE-5, WE-6, and WE-11,
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1 (3)
differ from those described above in that they are adjacent to or imbedded within
flatwoods (Laessle 1942). Pond WE-5 was located in an area of Placid fine sand,
depressional, downslope from longleaf pine/turkey oak sandhills. Pond WE-6 was
also downslope from longleaf pine/turkey oak sandhills but was bordered on one
side by upland hardwoods such as Chapman's oak (Q. chapmanii) and myrtle oak
(Q. myrtifolia) which are associated with sand pine (P. clausa) scrub habitat. The
soil mapped here was Pomello fine sand, which is a flatwoods soil with an organic
pan below the surface. Pond WE-11 was a flatwoods pond mapped with Pomona
fine sand, a poorly drained sand over a loamy subsoil (Puckett 1982). It was near a
xeric hammock located on deep sands and containing live oak (Q. virginiana) and
longleaf pine.
Ocala National Forest.-- Lake Delancy Pond, located in a section of the ONF
in southern Putnam County, is an area of sand pine scrub managed by the USDA
Forest Service for timber production. It is located on moderately well drained
Pomello sand (T. Bailey pers. comm), and the natural vegetation of the area is sand
pine, slash pine, scrub live oak (Q. geminata), myrtle oak, and saw palmetto
(Serenoa repens). Approximately 2 km to the east is a sand ridge of Astatula soils
that supports forests of longleaf pine and turkey oak. Just prior to the initiation of
this study, the forest surrounding the pond had been clear-cut, bedded and re-
planted with sand pine. A thick layer of muck and algae were present in this pond
and it held water through-out the period of this study without drying.
Climatic conditions.-- Average daily temperatures, annual precipitation, and
weather patterns are similar between the Putnam County study sites and the ANF
in Leon County (USDA, 1984; Readle, 1990). The average daily temperature for
both areas in summer is 270 C and in winter ranges from 11 C (ANF) to 120 C
(Putnam County). Annual precipitation ranges from approximately 142 cm per
year (Putnam County) to 152 cm per year (ANF). Most of the precipitation occurs
in the summer as a result of convective thunderstorms. October and November are
the driest months. Rain occurring in the winter results from frontal depressions
that originate in the northern U.S. and Canada. Water tables in uplands of north
and north-central Florida have seasonal highs in the winter and lows in the
summer.
Field Methods
Single linear transects were established in each pond by taking a compass
heading of 0 N at the center of each pond and walking perpendicular to the
topographic gradient to the surrounding upland edge. The 1989 sampling of BP
and GP deviated from this compass heading. A random compass direction was
selected for these two transects. Sampling points were begun at the center of each
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
pond and located at 5 m intervals until the upland boundary, as indicated by
vegetation (pines or oak hammock), was reached (Abrahamson et al. 1988). If the
next 5 m sampling point along the transect was completely within upland habitat,
the sampling was terminated at the previous location. Transect lengths varied
from 25 to 80 m depending on the size of the pond basin. At each of the sampling
points, percent ground cover was sampled within quadrats using a rectangular
vegetation sampling frame with dimensions 0.5 m x 2.0 m. To facilitate ocular
estimation of cover, 0.1 m portions of the sampling frame were shaded. Percent
cover was estimated for all plants (< 1 m tall or non-woody) rooted within the
quadrat. Plants were identified to the species level where possible. Bare soil
(classified as unvegetated), dead vegetation, surface water, and non-vascular plants
were also given cover estimates. In one pond (BP, 1989 sampling), a distinction
was made between a ground cover layer and a shrub layer. Shrubs, defined as
woody plants greater than 1 m in height, were sampled using 5 m x 5 m quadrats
located at 5 m intervals along the transect. In all other pond basins, shrubs at the
transect sampling locations were sampled within the same 1 m square quadrat as
the ground cover layer.
During each sampling in 1989 and 1990, a survey of the flora was made after
the transect sampling. Circuits were made around the pond basins from the center
to the upland boundary to opportunistically identify additional species missed on
the transects. This method of sampling was also used to obtain species
presence/absence data for LDP and RP.
Data Analysis
Analyses were chosen to address the research objective and to fit the field
methods used. Plant lists were compiled for each site. Plant species identification
and nomenclature follow Wunderlin (1982) and Clewell (1985). Only those 11
ponds sampled using transects during 1989 and 1990 were used in calculations.
Total species occurrence data in all ponds, including LDP and RP, were used to
make comparisons between sites.
To determine the similarities between the plant community at each pond, a
number of different methods was used. The most common plant species were
determined by finding those present in greater than 60% (7/11) of the ponds. Sixty
percent was an arbitrary limit set as indicative of presence in a high percentage of
samples, and plants found with this frequency were considered "constant" species
(Mueller-Dombois and Ellenberg 1974). The most common plant species were
identified from the 1990 transect data alone, then the 1989 transect data and data
from the circuit searches were added, and the most common plant species were
determined from the combined samples.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1 (3)
Percent cover values were used to calculate the dominant species in each pond
basin and for all ponds combined using the 1989 and 1990 transect data. The top
three species were chosen as co-dominants from a list of total percent cover ranked
from highest to lowest.
The floristic similarity between sites was determined using Sorensen's index of
similarity (SI)(Mueller-Dombois and Ellenberg 1974). This index was calculated
from species presence/absence and transect data from 1989 and 1990. It is
computed as follows:
SI = 2C X 100 A = # species, site 1
A+B B = # species, site 2
C = # species, common
to both sites
The results from the calculation of similarity indices were used to compare
species composition in patterns of zonation previously reported in the literature and
determine if similar patterns were present in the study ponds.
To determine if the vegetation of each pond corresponded to an index value
indicative of wetland, species identified within quadrats were categorized by their
wetland indicator status and given an associated ecological index value (El) (Table
2) (Reed 1988; Wentworth et al. 1988). Ecological index values range from 1, for
obligate wetland species, to 5, for obligate upland species. Plus (+) and minus (-)
designations specify, respectively, the higher (more frequently found in wetlands)
or lower (less frequently found in wetlands) part of the frequency range for a
particular species. When assigning the El, species with a plus received 0.5 less
than the El for that category and species with a minus received 0.5 more than the
El for that category. Plants identified only to genus were assigned the maximum
indicator status category and the maximum El if there were differences within the
genus. A plant community consists of hydrophytic vegetation if visually estimated
percent cover of obligate wetland species (OBL) and facultative wetland species
(FACW) exceeds coverage of facultative upland species (FACU) and obligate
upland species (UPL) or if the El < 3 (USEPA 1989; USEPA 1991).
Wetland index values (WIV) were calculated for each quadrat for each transect
across all ponds and all years using weighted averages of the percent cover data
(Wentworth et al. 1988). To calculate this index, relative abundance (R) of each
species in each quadrat was determined as percent cover of each individual species
divided by the total percent cover of all species in that quadrat. Calculation of the
WIV involved taking the sum of products of the relative abundances and ecological
index values of all species in each quadrat, divided by the sum of all the relative
abundances, as follows:
WIV = Z (RX EI) R = Relative abundance
ER El = Ecological index value
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
Table 2. Wetland Indicator Status and Ecological Index Values (EI) (Reed 1988; Wentworth et al. 1988).
Category Symbol Definition El
Obligate OBL Plants that occur almost always in wetlands under 1
Wetland natural conditions (estimated probability > 99%).
Facultative FACW Plants that usually occur in wetlands (estimated 2
Wetland probability > 67% to 99%) but also occur in non-
wetlands (estimated probability 1% to 33%).
Facultative FAC Plants with a similar likelihood of occurring in both 3
wetlands and nonwetlands(estimated probability
33% to 67%).
Facultative FACU Plants that sometimes occur in wetlands(estimated 4
Upland probability 1% to 33%), occur more often in non-
wetlands (estimated probability > 67% to 99%).
Obligate UPL Plants that occur rarely in wetlands (estimated probability 5
Upland < 1%) but occur almost always in non-wetlands under
natural conditions(estimated probability > 99%).
Percent cover data from each pond transect were used in conjunction with the
wetland indicator status of each species to determine the total percent cover in each
pond basin of OBL, FACW, FAC, FACU, and UPL species. These data were
compared by hydrologic status of each pond as expressed by months since each
pond had held water.
Species richness, Shannon's Index, and evenness were calculated for each set
of pond transect data. These data were also compared by hydrologic status at each
pond as expressed by months since each pond had held water. Species richness is
the total number of species found along each pond transect. Shannon's Index, H',
is a measure of the average degree of "uncertainty" in predicting the species of an
individual chosen at random from a collection of S species and N individuals in a
population (Shannon and Weaver 1949). As diversity increases, Shannon's Index
will also increase. The equation describing Shannon's Index is as follows:
H' = Z (pilnpi)
pi = proportional abundance of each
species; estimated from the
proportion of the number of
individuals of a species to the total
number of individuals in the
sample.
Evenness, E, was calculated as the ratio of H' to the natural log of species richness.
Evenness would be maximum when all species were equally abundant and would
decrease toward zero as the community diverged from evenness.
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(3)
RESULTS
A total of 112 vascular plant species were identified in the 13 ponds across all
3 sampling years. An additional 12 plants were only identifiable to genus. Of the
112 species, 30% were identified in only one of the 11 ponds for which there were
transect data; 64 (57%) were identified from the transect data alone; and the
balance of the species were identified from circuit searches made through the pond
basins. Of the species, 15% were present only in RP and 4% only in LDP. Of the
12 plants identified only to genera, 8 were the same genera as an identified species
and may have been one of those species. In addition to the vascular plants, three
groups of nonvascular plants were identified. Algae, Cladonia sp., and Sphagnum
sp. were present as ground cover in pond basins.
Only two species, Panicum hemitomon and Andropogon glomeratus, were
present in 60% of the ponds for which there were transect data (Table 3).
However, if the data for all ponds are combined, an additional six taxa are present
in at least 60% (8) of the 13 ponds. These include Rhexia mariana var. mariana,
Eupatorium leptophyllum, Rhynchospora spp., Ilex glabra, Cephalanthus
occidentalis, and members of the family Eriocaulaceae. Rhynchospora spp. and
members of the family Eriocaulaceae were lumped together because of the similar
habitat requirements of individual species and their similar zonation within pond
basins.
Co-dominant species in the 11 pond basins (Tables 4, 5) were represented by
21 vascular and 2 nonvascular plants. Panicum hemitomon had the highest total
percent cover in seven of the ponds. It was also a co-dominant in two additional
ponds, resulting in co-dominance in 82% of the ponds with transect data. Of the
co-dominant species, 78% were present in only one pond, 3 species were co-
dominant in two pond basins, and Eupatorium leptophyllum was co-dominant in
three ponds. Two non-vascular plants, Sphagnum sp. and Cladonia sp., were each
co-dominant in one pond. Of the vascular plants determined to be co-dominants,
52% were OBL, 33% were FACW, 10% were FAC, and 5% were FACU species.
No UPL species (Reed 1988) were co-dominants, but Cladonia sp. is an upland
associated species.
Similarity indices indicated that the similarity between ponds was generally
low. There were less than 50% shared species between most pond basins (Table
6). Of the transects sampled in 1990, only five pairwise comparisons of pond
vegetation (9%) had greater than 50% of their species in common. When the data
collected in 1989 from the two transects in BP and GP were compared to each of
the sets of data from the 1990 ponds, only the samples of vegetation from BP and
GP shared greater than 50% of their species. The WREC ponds were the least
similar to other ponds. The lowest SI was calculated when WE-5 and WE-11 were
compared with OS. Similarity indices were highest when the ANF ponds were
compared to each other.
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
Table 3. Plant species present on greater than 60% of 1990 transects (1990) OR in greater than 60 % of all
pond basins (ALL), data combined.
Plant Species 1990 All
Panicum hemitomon 11/11 13/13
Andropogon glomeratus 8/11 13/13
Rhexia mariana var. mariana 11/13
Eupatorium leptophyllum 10/13
Eriocaulaceae 9/13
Rhynchospora sp. 8/13
Ilex glabra 8/13
Cephalanthus occidentalis 8/13
Table 4. Percentage of total vegetated cover for each co-dominant species from transects in Apalachicola
National Forest (ANF) and Welaka Research and Education Center (WE), 1990. WIS=Wetland indicator
status (Reed 1988).
Pond
Species WIS ANF-1 ANF-3 ANF-4 WE-5 WE-6 WE- 1
Sphagnum sp. N/A 6
Dichanthelium erectifolium OBL 32 18
Panicum hemitomon OBL 8 34 65 54
Rhynchospora corniculata OBL 15
Rhynchospora glomerata OBL 20
Eriocaulon sp. OBL 13
Nymphaea odorata OBL 23
Lachnanthes caroliniana OBL 16
Ranunculus sceleratus OBL 18 48
Andropogon glomeratus FACW 11
Fimbristylis schoenoides FACW 18
Eupatorium leptophyllum FAC+ 26
Dichanthelium acuminatum FAC 24
Total % Cover
3 sp. combined 55 69 74 70 89 92
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I (3)
Table 5. Percentage of the total vegetated cover for each co-dominant species from transects in
Ordway/Swisher Memorial Sanctuary, 1989 and 1990. WIS=Wetland indicator status (Reed 1988).
Pond
WIS GP GP BP BP OS HP DP
Species (1989) (1989)
Axonopusfurcatus OBL 19
Leersia hexandra OBL 22 16
Panicum hemitomon OBL 39 12 52 29 22 44 59
Eleocharis rostellata OBL 14
Lachnocaulon anceps OBL 9
Rhexia mariana FACW+ 10
Panicum verrucosum FACW 30 35
Cyperus odoratus FACW 22
Ilexglabra FACW 7
Eupatorium leptophyllum FAC+ 20 14
Pinus palustris FACU+ 13
Cladonia sp. N/A 15
% Total Cover
3 sp. combined 68 58 81 83 58 68 87
Table 6. Sorensen Similarity Indices (SI) calculated from species present along vegetation transects in ponds
sampled October-November 1989 (BP-89 and GP-89) and May-July 1990.
ANF ANF WE WE WE GP BP
3 4 GP BP OS HP DP 5 6 11 89 89
ANF-1 52 53 31 32 24 52 25 23 15 17 33 26
ANF-3 53 30 31 29 43 24 15 15 8 39 44
ANF-4 19 32 18 37 25 15 15 8 27 32
GP 37 44 48 31 14 21 8 50 50
BP 28 36 42 29 10 11 48 54
OS 32 36 7 20 7 24 34
HP 38 17 26 10 37 36
DP 10 10 11 17 22
WE 46 50 23 22
WE 30 8 15
WE 8 16
GP -89 58
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
Table 7. Wetland Index Values calculated from transect vegetation data and Wetland Indicator Values.
All ponds sampled in 1990 except GP and BP as indicated. M-meters from pond center.
ANF ANF ANF GP GP BP BP OS HP DP WE WE WE
M 1 3 4 90 89 90 89 5 6 11
0 1.03 1.00 1.00 1.20 1.04 1.90 1.90 2.02 1.33 1.04 1.00 1.35 1.00
5 1.25 1.00 1.11 1.09 1.31 1.71 2.08 1.68 1.09 1.59 1.00 1.06 1.00
10 1.22 1.52 1.14 1.09 1.39 2.45 1.36 2.75 2.61 1.05 1.00 1.42 1.00
15 1.72 1.71 1.00 1.17 1.22 1.43 1.76 1.49 1.12 1.33 1.20 1.36 1.00
20 2.74 1.46 1.00 1.00 1.56 1.00 1.18 1.00 1.21 2.72 1.00 1.02 1.00
25 1.50 1.70 1.30 1.00 1.85 1.04 1.04 1.31 1.93 3.03 3.75 3.33 1.00
30 1.97 1.41 1.00 1.55 1.08 1.00 1.70 1.79 3.71 1.00
35 1.63 1.00 1.70 1.02 1.00 1.81 1.26 3.41 1.05
40 2.14 1.00 1.44 1.47 1.00 3.00 1.59 3.66 1.05
45 1.00 2.00 1.00 3.53 1.88 2.15
50 1.15 ---- -----
55 -- 1.00 ------------
60 1.15 ---------
65 -- 1.80 --------
70 1.77 -- --------
75 2.04 -----
80 2.57 --------
MEAN 1.58 1.57 1.14 1.30 1.51 1.46 1.33 2.03 1.58 2.39 1.49 1.59 1.13
Table 8. Percent Cover by Wetland Indicator Status, 1990 transects. 0 months since water indicates a pond
was flooded when sampled.
Total Percent Cover
Months
Since
Pond Water OBL FACW FAC FACU UPL
ANF-1 1 51 22 26 < 1 0
ANF-3 0 48 23 29 0 < 1
ANF-4 0 90 5 5 1 0
GP 12 72 23 2 2 1
BP 19 62 18 20 0 0
OS 4 41 45 9 3 2
HP 16 46 34 14 6 0
DP 84 69 3 1 27 < 1
WE-5 0 81 4 3 13 0
WE-6 0 72 26 0 2 0
WE-11 0 96 3 0 1 0
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(3)
Table 9. Species richness (S), Shannon's Diversity Index (H'), and Evenness (E) calculated from the 1989
and 1990 transect data. 0 months since water indicates that ponds were flooded when sampled.
Months
Since
Pond Water S H' E
ANF-1 1 15 2.07 0.76
ANF-3 0 16 1.91 0.69
ANF-4 0 15 1.71 0.63
GP (90) 12 17 1.92 0.68
GP (89) 4 15 2.14 0.79
BP (90) 19 10 1.42 0.61
BP(89) 11 13 1.66 0.65
OS 4 19 2.28 0.77
HP 16 12 1.81 0.73
DP 84 9 1.30 0.59
WE-5 0 11 1.76 0.74
WE-6 0 11 1.17 0.49
WE-11 0 9 1.29 0.59
Wetland index values were calculated for each quadrat for each vegetation
transect in 1989 and 1990, and a mean was calculated for each pond (Table 7).
The lowest mean value was 1.13 in WE-11, and the highest mean value was 2.39
in DP. These results are to be expected since, at the time of sampling, all Welaka
ponds were flooded, and DP had been dry longer than any other study pond.
Calculation of the total percent cover along the transects in each pond basin for
each category of wetland indicator class revealed that all ponds except OS had
OBL species as the largest component of total percent cover (Table 8). In OS,
there was only a slightly higher percent cover of FACW when compared to OBL
(4%). Even DP, which had been dry for at least 84 months, maintained a total
percent cover of OBL of 69%.
Species richness (Table 9) ranged from a low of nine species in DP and WE-
11 to a high of 19 species in OS. The ponds in ANF had the highest average
species richness, and the WREC ponds had the lowest. Species richness in ONF
ponds was similar to that in the ANF ponds. Among the ANF ponds and among
the WREC ponds, species richness was similar, but OSMP ponds varied from the
lowest to the highest number of species. Species richness was very high in RP, but,
this result was expected since the number of vegetation samples obtained from this
site were much higher than any other pond basin.
Calculation of Shannon's Index (H') resulted in a range of values from 1.17 in
WE-6 to 2.28 in OS (Table 6). Evenness (E) ranged from 0.49 in WE-6 to 0.79 in
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
GP(1989) (Table 9). The amount of time since each pond had held water when
sampled is also presented in Table 9.
DISCUSSION
Pond Similarities and Differences
The similarities found in plant community composition between ponds was
based primarily on the presence of the eight most commonly found taxa and the
study site within which each pond was located. Both similarities and differences
between ponds were related to differences in each pond's hydrologic cycle, as
measured by the time since each pond had held water. This related directly to soil
moisture conditions (LaClaire 1992). Flooded ponds lacked some of the dry
meadow species but had floating-leaved species that were absent from the dry
ponds. Dry meadow species and plants responding to declines in soil moisture
conditions were more abundant in dry pond basins. This is demonstrated by the
low similarity when WE-5 and WE-11 are compared to OS. The flooded WREC
ponds had greater than 80% total cover of OBL but very low total percent cover of
FACW (4% and 3% respectively). One Shot Pond, which had been dry for 4
months when sampled, had 41% total cover of OBL and 45% FACW. The FACW
species were responding to drawdown and specific moisture conditions for which
they are adapted.
Only four of the study ponds were sampled when drawdown had been recent,
and ruderal or annual/short-lived perennial type species, except for Eupatorium
leptophyllum, were not common in the pond basins. The transects in BP and GP
from 1989 and OS were sampled when drawdown had occurred less than 1 year
previous. One pond, ANF-1, had been dry only for a month when sampled, but
this was too soon for emergent vegetation to respond to the change in the
environment. All the other ponds were either flooded or had been dry a year or
longer. As a result, most of the co-dominant species identified in the ponds were
perennials, as were most of the total species identified across all ponds and all
years. Of course, additional species may have been present as vegetative
propagules or as seeds in the seed bank of ponds. Since annuals have a short life
cycle, frequent sampling would be required for a complete species list.
Differences between the ponds are obvious from the fact that 78% of the co-
dominant species identified in each pond were present in only one pond. However,
many of these co-dominant species, as well as other component species of the
ponds, shared life histories that were in some way adapted for the cyclic changes in
the temporary pond basin. The most obvious similarity was the dominance of
perennial species in the ponds. Other similarities involved adaptations developed
in response to changes in hydrologic cycle. Several species (Dichanthelium
sabulorum, Juncus repens, and Sagittaria graminea) showed a wide range of shoot
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(3)
and leaf growth forms or growth phases depending on soil moisture conditions.
Others (for example, Hypericum fasciculatum) had a needle-like leaf form typical
of many stress tolerant species (Grime 1979). Other species responded in the same
way to a particular stage in the hydrologic cycle. This can be seen in ponds where
drawdown had been recent. Some plants represented species that colonize the bare
mud which becomes available after drawdown. Rapid plant growth was supported
by the nutrient-rich, moist soil present in a temporary pond at this time. The
period available for growth may be relatively short, and, thus, these species were
annuals with a high potential growth-rate or short-lived perennials that were
adapted to exploit this intermittently favorable environment (Grime 1979).
Panicum verrucosum (an annual) is an example of this type of strategy. It had the
highest percent cover on the 1989 transects in BP and GP and had set seed at the
time of sampling. In 1990, the species was not found in either BP or GP. It is
likely that its disappearance reflects the declining level of soil moisture between
sampling events (LaClaire 1992) and that continued drought conditions did not
favor seed germination. Another example of a drawdown species is the annual or
short-lived perennial, Cyperus odoratus. It shared the highest percent cover with
P. hemitomon on transects in OS. It occurred at the lowest elevation in the pond
center and disappeared shortly after it set seed (LaClaire unpubl. data). This result
fits a pattern where the deep area of a pond or marsh changes community
composition seasonally depending on drying conditions (Botts and Cowell 1988).
A perennial species, Eupatorium leptophyllum, was co-dominant in BP (1990), HP,
and ANF-3. This ruderal species is also adapted to exploit the bare soil exposed
after the pond dries. However, it requires less soil moisture, as indicated by its
FAC+ status, and so moves into the pond basin later in the pond drying cycle than
P. verrucosum or C. odoratus. It occurred throughout the pond basins when soil
was exposed and moisture conditions were appropriate.
Some differences between ponds can be explained by differences in the
surrounding habitat. Low similarity between the WREC ponds and other study
ponds can be explained partly by the association of flatwoods vegetation with the
WREC ponds and not the other study sites. Another explanation may relate to the
selection of these ponds for study. None of the ponds at WREC has been verified
as breeding ponds for the Florida gopher frog or the striped newt. If they are not,
in fact, breeding sites, this may relate to differences in the pond plant communities.
The higher similarities that resulted when ponds were compared within study sites
suggests other unknown habitat variables.
Panicum hemitomon was the only species present in every pond sampled. The
distribution of this species was a good indicator of the extent of previous flooding
in the pond basin, and its highest elevation in each pond roughly corresponded to
the average high water mark (Abrahamson et al. 1984; Lowe 1986; LaClaire
unpubl. data). Panicum hemitomon cannot tolerate long-term flooding, and, thus,
its absence in flooded pond centers demonstrated a persistent flooding event. The
above-ground growth of P. hemitomon tends to be fibrous and resistant to
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
decomposition. Its stalks may remain standing even if a pond has not filled for
several years, and it is able to survive many years of dry pond conditions, as
exemplified by the results from DP. Due to its tendency to grow in thick,
monotypic stands, it probably acts to maintain the wetland environment by
inhibiting the growth of upland species and reducing the oxidation of the soil
organic matter that is crucial for nutrient cycling in the pond basin. In this way, P.
hemitomon protects the wetland environment; the hydric soil and seedbank remain
intact until another flooding event.
Pond Zonation
The results of this study and previous work in upland temporary pond basins in
north and north-central Florida (Franz and Hall 1991; LaClaire and Franz 1991;
LaClaire 1992) have revealed a pattern of zonation with similarities to other
descriptions of temporary ponds (Fig. 1). Water-filled ponds often contain
floating-leaved plants and submergents in the deepest areas (Water Lily Zone) and
tall and short emergents at the pond edge (Sedge Prairie Zone). When the ponds
dry, emergent grasses fill these zones in the previously flooded portions of the
basin. Further upslope, a band of Hypericum fasciculatum (Sandweed Zone)
commonly occurs, typically followed by a band of Andropogon spp. (Bluestem
Grass Zone). Continuing upslope, additional bands of vegetation are found in dry
meadows (Dry Meadow Zone) that occur as transitional zones adjacent to the
longleaf pine dominated uplands. In some ponds, a fire shadow is present upslope
of the Dry Meadow Zone which contains fire intolerant evergreen shrubs
(Evergreen Shrub Zone) and oaks (Xeric Hammock Zone).
The two most common plant species found in the study ponds, Panicum
hemitomon and Andropogon glomeratus, created the most obvious zonation in the
pond basins overall. Both of these species are perennials with tall, persistent stems
that are resistant to decomposition. Panicum hemitomon was the dominant species
in the Sedge Prairie Zone and often defined its boundaries. Andropogon
glomeratus defined the Bluestem Grass Zone. In temporary ponds, P. hemitomon
reproduces most commonly vegetatively, but A. glomeratus sets seed that are wind-
dispersed. The result of these differences in reproduction can partially explain
overlapping zones in some of the ponds. Panicum hemitomon occurred generally
as a uniform zone. Andropogon glomeratus was generally present along the outer
edges of the pond, but it was also present in dry pond centers probably as a result of
conditions appropriate to its seed germination.
The six additional species considered most common in the combined data sets
represented typical plants of temporary pond zones with the exception of
Eupatorium leptophyllum. Species dominance and the extent of zonation within
BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(3)
UPLANDS
POND BASIN
ORGANIC LAYER
UPLANDS
ZONES
HP= High
Pine
Xeric
XH=
XH- Hammock
Evergreen
E=
Shrub
D= Dry
Meadow
A Bluestem
Grasses
H Sandweed
S= Sedge
Prairie
W= Water Lily
Figure 1. Plant community structure in temporary pond basins.
each study pond varied depending on water depth or, if ponds were dry, on how
recently ponds had held water. Rhynchospora spp. and members of the family
Eriocaulaceae were the most common plants in the Sedge Prairie Zone after
Panicum hemitomon. These species were co-dominant in flooded ponds and those
recently dried (ANF and WREC ponds, OS) and less common in ponds that had
been dry longer. Rhexia mariana var. mariana occurred as part of the Dry
Meadow Zone. Two shrubs, Ilex glabra and Cephalanthus occidentalis, were also
"constant" species in the study ponds. They are typical members of the Evergreen
Shrub Zone and are indicative of a lack of fire in at least part of the basin.
The most common species, and their representative patterns of zonation, have
been described from other ponds with fluctuating water levels in similar habitats
on the lower coastal plain (Huffman 1982; Abrahamson et al. 1984; Lynch et al.
1986; Botts and Cowell 1988; Bridges and Orzell 1989). The most common
overlap between the study ponds and the literature were the grasses, sedges and
herbs of the Water Lily and Sedge Prairie Zones such as species of Panicum,
Rhynchospora, Xyris, and the Eriocaulaceae. Other dominant species frequently
mentioned in the literature were Hypericum fasciculatum and H. myrtifolium
LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA
(Sandweed Zone), Andropogon glomeratus (Bluestem Grass Zone), and Rhexia
mariana var. mariana (Dry Meadow Zone).
The importance of seed banks in maintaining the temporary pond community
was not addressed directly in this study. However, the seed bank is likely to be
very important to the maintenance of the wetland community and a contributing
factor to pond zonation. Many wetland plant species disperse floating seeds and/or
require specific intervals of inundation or desiccation for seed germination (van der
Valk 1981). The position of these species may be dependent on the extent of
flooding in the basin before drawdown, as well as the duration of drawdown (Lowe
1986; Hull et al. 1989). An overlapping distribution of plant species perhaps
indicates similar hydrologic tolerances, but it may also indicate similar suitability
of the substrate for seed settling, seed germination, and plant growth after the seeds
have dispersed to that position (Hull et al. 1989).
Wetland Index Values (WIV)
All of the temporary pond basins studied had WIV less than 3, and, as a result,
their plant communities can be considered wetland vegetation according to the
Federal Manual for Identifying and Delineating Jurisdictional Wetlands (USEPA
1989). Wetland index values generally increased along the transects as the upland
boundary was reached. However, there was not a simple relationship between the
index values and a gradient of soil moisture, described by meters from the pond
center, because of confounding elevation and substrate effects (LaClaire unpubl.
data). The lowest mean WIV was calculated for WE- 1. This was the result of the
almost complete dominance (96%) of this pond basin by OBL. The highest mean
WIV was calculated for DP and was a result of the co-dominant UPL species found
in it. However, DP maintained OBL as the highest total percent cover and, as a
result, maintained its status as wetland.
Species Richness, Diversity, and Hydrology
The relationship between status of each pond in its hydrologic cycle, as
represented by time since it was flooded, and species richness and diversity is
complex. The lowest species richness was found in DP, which had been dry longer
than any other pond basin, but also in WE-11, which was flooded at the time of
sampling. Both ponds had low values for evenness as a result of dominance by
Panicum hemitomon, 59% of total cover for DP and 54% of total cover for WE-11.
Welaka pond #11 was almost entirely flooded (35/45 m along the transect) and this
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