2007 SOUTHEASTERN NATURALIST 6(1):125–134
Establishing a Baseline and Faunal History in Amphibian
Monitoring Programs: The Amphibians of Harris Neck, GA
C. Kenneth Dodd, Jr.1,* and William J. Barichivich1
Abstract - We conducted an intensive inventory of Harris Neck National Wildlife
Refuge in coastal Georgia to determine the feasibility of establishing an amphibian
monitoring program at this location. Thirteen semi-aquatic amphibian species were
identified at 21 locations. Amphibian species richness at Harris Neck was similar to
that of nearby barrier islands. The amphibian fauna of Harris Neck has long been
affected by human-induced landscape changes, including the inadvertent introduction
of tadpoles from distant fish hatcheries and the creation of artificial impoundments.
Land-use history provides important information necessary to understand current
amphibian distribution, especially when census data are used to establish a baseline
from which to monitor future status and trends.
Introduction
The decline and extinction of many amphibian taxa throughout the world
has sparked considerable interest in the biology and biogeography of these
species (Houlahan et al. 2000, Stuart et al. 2004). The causes of declines are
complex and may be interrelated (Blaustein and Kiesecker 2002, Collins and
Storfer 2003, Corn 2000, Pounds et al. 2006). There is a crucial need for
current information on the distribution of amphibians across a landscape, so
that species and populations can be monitored for signs of imperilment.
Accordingly, much attention has been directed at how to monitor amphibians
(Dodd et al., in press), and whether status should be measured in terms
of changes in abundance or site occupancy (e.g., MacKenzie et al. 2005,
Schmidt 2003, Schmidt et al. 2002).
As part of the interest in monitoring amphibians, the US Congress
authorized the US Geological Survey to undertake a national assessment of
the status of amphibians within the United States, and to develop a research
program designed to detect trends and identify factors which might be
causing declines. This program, the Amphibian Research and Monitoring
Initiative (ARMI) (Corn et al. 2005, Muths et al. 2005), currently focuses
on Department of Interior lands, which in the Southeast are largely under
the jurisdiction of the National Park Service and US Fish and Wildlife
Service. We identified four National Wildlife Refuges (NWR) on the
Coastal Plain to determine their feasibility as long-term monitoring sites,
including Harris Neck NWR (HNNWR) in mid-coastal Georgia. Historical
information on the amphibians of HNNWR is nearly nonexistent, as we
have found records of only two Hyla cinerea (Schneider) (Green
1US Geological Survey, 7920 NW 71st Street, Gainesville, FL 32653. *Corresponding
author -Terrapene600@gmail.com.
126 Southeastern Naturalist Vol. 6, No. 1
Treefrogs) collected from Harris Neck (J. Jensen, Georgia Department of
Natural Resources, Forsyth, GA. pers. comm.), and there are no publications
discussing its amphibian fauna.
Knowledge of which species occur within an area and the location of
potential long-term monitoring sites must be available before a monitoring
project can be established (Dodd et al., in press). Inasmuch as no herpetological
inventory had been conducted at HNNWR, our initial objective was
to identify potential sampling sites and species present. During conversations
with refuge staff, we became aware of the complex human-related
impacts to the land at Harris Neck, including impacts that had taken place at
least since the area was settled by Europeans and Africans in the 1700s.
Many of the likely impacts were immediate and related to refuge development
and operations during the last 40 years. However, we also began to
question how human impacts as long ago as 300 years might have affected
the persistence of Harris Neck’s amphibian fauna.
If initial monitoring results establish a baseline with which future trends
may be compared, does this baseline represent a fauna that is “natural” (i.e.,
representative of populations undisturbed by humans), highly disturbed, or
somewhere in-between? This question becomes particularly important since
monitoring programs generally assume that the results taken within one area
can be extrapolated to a wider area of inference (Thompson et al. 1998). In
this paper, we report on the results of our inventory, and note the importance
of having an understanding of long-term human history on sites chosen for a
monitoring program.
Materials and Methods
Study site
Harris Neck NWR is located ca. 46 km south of Savannah and 31 km
north of Darien, in McIntosh County, GA (Fig. 1). The refuge comprises
1255 hectares of mostly coastal deciduous and oak woodlands, grasslands,
former cropland, and both naturally regenerated and planted pine; it is
surrounded by salt marshes and tidal creeks. Harris Neck became a National
Wildlife Refuge in 1962, and is currently managed primarily for waterfowl
and wading birds, including Mycteria americana Linnaeus (Wood Stork).
Nearly all the wetlands at Harris Neck are man-made impoundments, modified
former tidal creeks, or ditches and borrow pits.
The land now comprising HNNWR has had many uses. Most impacts on
amphibians likely resulted from habitat alteration, as the land changed from
a subtropical maritime forest to plantation, later to small-farm agriculture,
then to an area of intensive technological development and potential exposure
to toxic chemicals (gasoline and the by-products of a military base), to
abandonment, and finally to a region characterized by intensive semi-natural
wildlife management.
In order to understand the distribution of amphibians at HNNWR, we
examined all available materials relating to land use since the area was
2007 C.K. Dodd, Jr. and W.J. Barichivich 127
settled by Europeans and their African slaves about 1740 (see Sullivan 1997
for a thorough review). Land grantees established plantations through the
latter part of the 1700s for sea-island cotton and rice production. Plantation
agriculture continued until the Civil War. None of the crude maps we have
seen indicate the presence of any freshwater wetlands on the property,
although the location of artesian wells is noted.
After the Civil War, plantations were subdivided and largely occupied
by former slaves. Agriculture shifted from labor-intensive cash crops to
subsistence farming and timbering, with some free-range hogs and cattle.
In 1890, the tobacco tycoon Pierre Lorillard established a summer mansion
on HNNWR, and records indicate the presence of outdoor fountains and
pools. In the 1930s, an airfield was established at HNNWR for passenger
airliner emergency use. In 1942, the Army constructed Harris Neck Air
Base, near the former civilian airfield, on 545 ha taken from African-
American farmers, and the community of Harris Neck ceased to exist.
After years of county fiscal and environmental mismanagement after
World War II (Sullivan 1997), the Federal government reclaimed the land
in 1962 and turned it over to the US Fish and Wildlife Service. No records
mention wetlands or streams. Large sections of the former air base are
covered by deteriorating tarmac.
Figure 1. Map of Harris Neck National Wildlife Refuge, McIntosh County, GA showing
the location of aquatic sampling sites. Lines within the map indicate the system of roads.
All wetlands were regularly sampled; no amphibians were found at Bluebill Pond
because of its brackish water. H indicates refuge headquarters compound.
128 Southeastern Naturalist Vol. 6, No. 1
Surveys
Most amphibians of the southeastern Atlantic Coastal Plain breed in
wetlands (streams, ponds, lakes, swamps). We therefore focused sampling in
aquatic habitats to inventory amphibian species richness, identify potential
sites for long-term monitoring, and determine the distribution of breeding
sites on the refuge. This focus allowed us to maximize species-detection
probabilities and examine important covariates (e.g., pH, fish predators)
influencing presence. We conducted six 3-day surveys from March to October
in 2004 and 2005, supplemented by a few short observational surveys at
other times. All wetlands were visited multiple times each year.
Aquatic sampling consisted of: the use of dip nets (HDD-2 with 3/16” sq.
Delta mesh; Memphis Net and Twine Co., Memphis, TN) by 2–4 people for
a total of 10–30 min per site, depending on the size of the wetland; 2–4
crayfish traps/site for ca. one continuous 48-hr period (Johnson and
Barichivich 2004); diurnal and nocturnal aural surveys for two nights (incidental
observations and by using automated frog-call data loggers at 5 sites
per visit; Barichivich 2003); and visual encounter observations. We collected
water-quality data at 12 ponds (water temperature [ºC], conductivity
[mS/cm], pH, dissolved oxygen [mg/l], and % dissolved oxygen) using a
Hydrolab® Quanta® water-quality meter; these parameters were measured at
10 ponds on more than one visit.
Terrestrial sampling supplemented wetland surveys, and included field
searches (i.e., visual encounter surveys for animals in the open and under
cover objects, e.g., logs, rocks) and road cruises (i.e., making opportunistic
observations while driving roads, typically at night). We searched a number
of terrestrial locations, particularly woodlands in the northeast near an old
army bunker, the terrestrial areas below Woody dike, various areas along the
wildlife drive, and areas adjacent to Lucas Pond.
Results
Thirteen amphibians (12 species of frogs and one species of salamander)
were recorded during our surveys at HNNWR (Table 1). Species richness
was similar to some of the southern Atlantic Coast barrier islands, although a
great deal of variation occurs among islands (Fig. 2). Rana sphenocephala
Cope (Southern Leopard Frog) was found at the most sites at Harris Neck
(14), followed by H. cinerea at 11 sites. Hyla gratiosa LeConte, (Barking
Treefrog) was not seen during 2004, and only a single calling individual at
Borrow Pond (Fig. 1) has thus far been observed. Hyla squirella Bosc
(Squirrel Treefrog) was rarely heard around any of the wetlands, but was
commonly observed around refuge headquarters at night.
The most amphibians recorded at single sites (8) were found at a small,
fishless borrow pit pond (Borrow Pond) and at a large impoundment (Goose
Pond, bordered on the north by shallow flooded grasses). Only one species
was found in a shallow, seasonally flooded roadside ditch, a fountain pool at
2007 C.K. Dodd, Jr. and W.J. Barichivich 129
Table 1. Amphibian species occurrence at sampling sites on Harris Neck National Wildlife
Refuge, McIntosh County, GA, 2004–2005. No amphibians were found in purely terrestrial
habitats, except while crossing roads on rainy nights or at the refuge headquarters. A.g. = Acris
gryllus, B.t. = Bufo terrestris, G.c. = Gastrophryne carolinensis, H.c. = Hyla cinerea, H.f. =
Hyla femoralis, H.g. = Hyla gratiosa, H.s. = Hyla squirella, N.v. = Notophthalmus viridescens,
P.c. = Pseudacris crucifer, P.o. = Pseudacris ocularis, R.c. = Rana catesbeiana, R.g. = Rana
grylio, R.s. = Rana sphenocephala, and # = No. of species observed.
Site A.g. B.t. G.c. H.c. H.f. H.g. H.s. N.v. P.c. P.o. R.c. R.g. R.s. #
Borrow Pond X X X X X X X X 8
Church Ditch X 1
Culvert Pond X X 2
Goose Meadow X X X 3
Goose Pond X X X X X X X X 8
Greenhead Pond X X X X X X 6
Lucas Borrow X X X 3
Lucas Pond X X X X X X 6
Lucas Seepage X X 2
N Runway Ditch X X X X 4
Plantation Fountain X 1
Red Maple Swamp X X X 3
Snake Bog X X X X X 5
Snipe Pond 1 X X 2
Snipe Pond 2 X 1
Snipe Pond 3 X X X X X 5
Teal Pond X X X X X 5
Wigeon Pond X X X X X X 6
Woody Pond X X X X X X X 7
Woody Swamp X X X 3
Refuge Headquarters X X X 3
No. of sites 7 5 6 11 3 1 2 7 9 9 6 4 14
w/ observations
Figure 2. The relationship
between amphibian species
and barrier island size
(ha) for barrier islands extending
from Maryland to
Georgia (N = 25). Whereas
the regression is significant
(F = 5.35, p = 0.03),
little of the variance is explained
(r2 = 0.189).The
rectangle indicates Harris
Neck. Data from Gibbons
and Coker (1978), Gibbons
and Harrison (1981),
Conant et al. (1990),
Mitchell and Anderson
(1994), Laerm et al.
(2000), and Shoop and
Ruckdeschel (2003).
130 Southeastern Naturalist Vol. 6, No. 1
the Lorillard homesite, and in one segment of a sometimes interconnected
much larger impoundment (Snipe Pond). Amphibians were recorded at every
wetland on the refuge, even at a shallow pool at the end of a culvert (Culvert
Pond) and ditches adjacent to the old air base north runway (North Runway
Ditch). Fish were present in all wetlands at HNNWR except at Borrow Pond.
No terrestrial amphibians were observed during visual encounter surveys;
however, amphibians were particularly abundant on paved roads after
heavy rains, and many species were detected calling. We found several
species (e.g., B. terrestris Bonnaterre [Southern Toads], H. cinerea) distributed
essentially throughout the refuge in 2005, despite the fact that only a
single B. terrestris was observed during all surveys in 2004. During a single
pass on the wildlife drive (16 May 2005), for example, we heard 7 species
calling: Acris gryllus LeConte (southern cricket frog), B. terrestris, H.
cinerea, H. femoralis Bosc, Pseudacris ocularis (Bosc and Daudin) (Little
Grass Frog), Rana catesbeiana Shaw (American Bullfrog), and R. grylio
Stejneger (Pig Frog).
2004
We made one scouting trip to the refuge in January 2004, followed by
three intensive sampling periods in 5–7 April, 29–30 June, and 19–20
October, and a very short visit to Borrow Pond and Plantation Fountain on
24 November. We detected 12 amphibian species comprising 11 species of
frogs and one salamander at 19 wetland sites. We collected water-quality
field parameter data at one location in April and 9 locations in both June and
October. pH values generally were acidic (4.5–6.8) except at Blue Bill
(April, 7.5), Goose (October, 7.3), Snipe (June, 7.8), and Teal (October,
7.2). The lowest pH was 4.5 in Borrow Pond in October. Dissolved oxygen
values were very low in all wetlands (0.34–4.95 mg/l), but conductivity was
relatively high everywhere (to 0.469 mS/cm), except for Borrow Pond
(0.019, 0.03). Percent DO values were very low (< 25%), except at Snipe
Pond (101.3%) and Borrow Pond (62.2%) in June. Pond water temperatures
varied between 19.3 and 27.6 ºC during sampling.
2005
Fifteen wetland sites were sampled in 21–23 March, 12 in 16–18 May,
and 9 in 25–27 July. Three new wetland sites were identified after frogs
were heard calling from them during a period of heavy rainfall: Church
Ditch (along main road across from Friendship Baptist Church), Goose
Meadow (adjacent to the dirt road along the southeast side of Goose Pond),
and Snake Bog (a seepage boggy habitat along the main road near Friendship
Baptist Church). Church Ditch only held water after heavy rains in
March, and P. ocularis were heard calling from its margins. Goose
Meadow is an extensive shallow water area, but it only holds water after
substantial rainfall. Bufo terrestris bred successfully there in March in
large numbers. Water remained in May, but no tadpoles were seen; by July,
the area was dry and small juvenile toads were observed. Snake Bog had
2007 C.K. Dodd, Jr. and W.J. Barichivich 131
choruses of P. ocularis, H. femoralis, H. cinerea, and A. gryllus during
night surveys in May, but no tadpoles were seen.
Values for pH again were generally acidic, with a range of 3.9 to 8.7 and
a mean among all samples of 6.0. Conductivity was generally low, less than
0.397 mS/cm at all sites. Dissolved oxygen (DO, mg/l) and % DO varied
considerably, ranging from 0.11 mg/l and 1.4% to 14.87 mg/l and 159%.
Water temperatures ranged from 13.8 ºC to 28.9 ºC.
Discussion
The only published records of amphibian faunas from the coastal regions
of Georgia are for the barrier islands (Laerm et al. 2000, Shoop and
Ruckdeschel 2003) and two small national park units (Tuberville et al.
2005). Although not a barrier island, Harris Neck is not physically connected
to the mainland, but is separated by a tidal channel and a salt marsh.
All of the species on HNNWR have been found on many of Georgia’s barrier
islands (Laerm et al. 2000, Shoop and Ruckdeschel 2003), particularly
Sapelo Island (Fig. 1), located ca. 23 km to the southeast (Laerm et al. 1999,
Martof 1963). Two species found on Sapelo—Amphiuma means Garden and
Scaphiopus holbrookii (Harlan)—have not been found at Harris Neck.
The US Fish and Wildlife Service developed Harris Neck as a waterfowl
and heron refuge. Impoundments were created by closing off the
downstream portions of tidal creeks and deepening the upstream portions
(Bluebill, Woody, Wigeon, Lucas), creating shallow ponds (Goose,
Greenhead) with interconnecting canals (Teal), and filling the depressions
with fresh water from artesian wells. These impoundments are
periodically drawn down and may be further excavated to remove vegetation
and debris. Borrow pits (Borrow, Lucas Borrow, North Runway
Ditch), depressions resulting from road construction (Church, Culvert,
possibly Snake Bog), seepages under dams (Woody Swamp, Lucas Seepage),
and a fountain at the site of the former Lorillard mansion are the
only other wetlands on HNNWR.
Waterfowl and water bird management have undoubtedly affected amphibian
presence at HNNWR by providing abundant aquatic breeding sites,
including a few small areas that are free of fish, in an area previously devoid
of extensive wetlands. Fishless wetlands allow pond breeders such as H.
femoralis and H. gratiosa access to an area in which they otherwise could
not reproduce. At the same time, management practices such as fish stocking
may have inadvertently mixed faunas. We found tadpoles resembling upper
coastal plain phenotypes of larval R. catesbeiana (olive bodies with small
salt and pepper spotting) in ponds where fish had been stocked, adjacent to
ponds (into which fish had not been stocked) containing phenotypes of R.
catesbeiana from the lower coastal plain (deep green dorsally and bright
yellow ventrally). This could be the result of faunal mixing, inasmuch as
fish are imported from Bo Ginn, GA, and Orangeburg, SC; fish shipments
have not been screened for tadpoles or adult amphibians.
132 Southeastern Naturalist Vol. 6, No. 1
Despite all the human-created landscape changes at HNNWR, amphibians
are still relatively abundant. Somewhat brackish-tolerant species are
common and widely distributed (e.g., R. sphenocephala, B. terrestris),
whereas fish-intolerant species (H. femoralis, H. gratiosa) are present but
rare. As on most barrier islands, caudate species richness is low. The fauna is
similar to what Shoop and Ruckdeschel (2003) term the Pleistocene and
Holocene relict amphibian faunas, that is, faunas which reflect the complex
changes in sea level which have occurred over the last several million years.
The absence of certain species (e.g., A. means, S. holbrookii Harlan) from
the HNNWR fauna likely reflects the absence of historic wetlands on
HNNWR, changes during the long period of human use, or a combination
thereof. The current HNNWR fauna likely resulted from geologic changes
during the Pleistocene and Holocene, nearness to mainland faunas, and
human activities, particularly the introduction of tadpoles during fish stocking
and the creation of artificial impoundments.
When developing long-term monitoring programs, it is important to understand
the biogeography and recent history of the fauna to be monitored. If
faunas are highly “artificial,” not representative of the wider community, or
recently disturbed, then the area of inference from baseline inventories may
have limited applicability. Understanding the history of land-use in a monitoring
program provides important covariates to understanding current amphibian
distribution, status, and trends. As Jackson (2001) so rightly points out,
understanding the present is not always the key to understanding the past or
the future.
Acknowledgments
We thank Deb Barnard-Keinath and Karen Pacheco at of Harris Neck NWR and
John Robinette of Savannah Coastal Refuges complex for providing access, assistance,
and housing. Joe Mitchell provided information on island size. We thank the
SE ARMI field crew for their hard work: Linda Casey, Julia Earl, Denise Gregoire,
Margaret Gunzburger, and Jennifer Staiger. J. Whitfield Gibbons, Margaret
Gunzburger, John Jensen, Lora Smith, and two anonymous reviewers provided
helpful comments on the manuscript. This research was conducted under USFWS
Special Use Permit 41620-04016 from the Savannah Coastal Refuges complex.
Literature Cited
Barichivich, W.J. 2003. Appendix IV. Guidelines for building and operating remote
field recorders (automated frog-call data loggers). Pp. 87–96, In C.K. Dodd, Jr.
(Author). Monitoring Amphibians in Great Smoky Mountains National Park. US
Geological Survey Circular 1258, Tallahassee, FL. 117 pp.
Blaustein, A.R., and J.M. Kiesecker. 2002. Complexity in conservation: Lessons
from the global decline of amphibian populations. Ecology Letters 5:597–608.
Collins, J.P., and A. Storfer. 2003. Global amphibian declines: Sorting the hypotheses.
Diversity and Distributions 9:89–98.
Conant, R., J.C. Mitchell, and C.A. Pague. 1990. Herpetofauna of the Virginia
barrier islands. Virginia Journal of Science 41:364–380.
2007 C.K. Dodd, Jr. and W.J. Barichivich 133
Corn, P.S. 2000. Amphibian declines: Review of some current hypotheses. Pp. 663–
696, In D.W. Sparling, G. Linder, and C.A. Bishop (Eds.). Ecotoxicology of
Amphibians and Reptiles. SETAC Press, Pensacola, FL. 877 pp.
Corn, P.S., M.J. Adams, W.A. Battaglin, A.L. Gallant, D.L. James, M.L. Knutson,
C.A. Langtimm, and J.R. Sauer. 2005. Amphibian Research and Monitoring
Initiative: Concepts and implementation. US Geological Survey, Scientific Investigations
Report 2005–5015. 23 pp.
Dodd, Jr., C.K., J. Loman, D. Cogalniceanu, and M. Puky. In press. Monitoring
amphibian populations. In H.H. Heatwole and J.W. Wilkenson (Eds.). Conservation
and Decline of Amphibians. Amphibian Biology, Volume 9A, Surrey Beatty
and Sons, Chipping Norton, New South Wales, Australia.
Gibbons, J.W., and J.W. Coker. 1978. Herpetofaunal colonization patterns of Atlantic
Coast barrier islands. American Midland Naturalist 99:219–233.
Gibbons, J.W., and J.R. Harrison III. 1981. Reptiles and amphibians of Kiawah and
Capers Islands, South Carolina. Brimleyana 5:145–162.
Houlahan, J.E., C.S. Findlay, B.R. Schmidt, A.H. Meyer, and S.L. Kuzmin. 2000.
Quantitative evidence for global amphibian population declines. Nature
404:752–755.
Jackson, J.B.C., 2001. What was natural in the coastal oceans? Proceedings of the
National Academy of Science, USA 98:5411–5418.
Johnson, S.A., and W.J. Barichivich. 2004. A simple technique for trapping Siren
lacertina, Amphiuma means, and other aquatic vertebrates. Journal of Freshwater
Ecology 19:263–269.
Laerm, J., T.C. Carter, M.A. Menzel, T.S. McCay, J.L. Boone, W.M. Ford, L.T.
Lepardo, D.M. Krishon, G. Balcomb, N.L. van der Maath, and M.J. Harris. 1999.
Amphibians, reptiles, and mammals of Sapelo Island, Georgia. Journal of the
Elisha Mitchell Scientific Society 115:104–126.
Laerm, J., N.L. Castleberry, M.A. Menzel, R.A. Moulis, G.K. Williamson, J.B.
Jensen, B. Winn, and M.J. Harris. 2000. Biogeography of amphibians and reptiles
of the Sea Islands of Georgia. Florida Scientist 63:193–231.
MacKenzie, D.I., J.D. Nichols, J.A. Royle, K.H. Pollock, L.L. Bailey, and J.E.
Hines. 2005. Occupancy Estimates and Modeling: Inferring Patterns and Dynamics
of Species Occurrence. Academic Press, San Diego, CA. 324 pp.
Martof, B.A. 1963. Some observations on the herpetofauna of Sapelo Island, Georgia.
Herpetologica 9:70–72.
Mitchell, J.C., and J.M. Anderson. 1994. Amphibians and reptiles of Assateague and
Chincoteague islands. Virginia Museum of Natural History Special Publications
2:i–120.
Muths, E., R.E. Jung, L. Bailey, M.J. Adams, P.S. Corn, C.K. Dodd, Jr., G. Fellers,
W.J. Sadinski, C. Schwalbe, S. Walls, R.N. Fisher, A.L. Gallant, W.A. Battaglin,
and D.E. Green. 2005. The US Department of Interior’s Amphibian Research and
Monitoring Initiative (ARMI): A successful start to a national program. Applied
Herpetology 2:355–371.
Pounds, J.A., M.R. Bustamante, L.A. Coloma, J.A. Consuegra, M.P.L. Fogden,
P.N. Foster, E. La Marca, K.L. Masters, A. Merino-Viteri, R. Puschendorf, S.R.
Ron, G.A. Sánchez-Azofeifa, C.J. Still, and B.E. Young. 2006. Widespread
amphibian extinctions from epidemic disease driven by global warming. Science
439:161–167.
134 Southeastern Naturalist Vol. 6, No. 1
Schmidt, B.R. 2003. Count data, detection probabilities, and the demography, dynamics,
distribution, and decline of amphibians. Comptes Rendus Biologies
326:S119–S124.
Schmidt, B.R., M. Schaub, and B.R. Anholt. 2002. Why you should use capturerecapture
methods when estimating survival and breeding probabilities: On bias,
temporary emigration, overdispersion, and common toads. Amphibia-Reptilia
23:375–388.
Shoop, C.R., and C.S. Ruckdeschel. 2003. Herpetological biogeography of the
Georgia Barrier Islands: An alternative interpretation. Florida Scientist
66:43–51.
Stuart, S.N., J.S. Chanson, N.A. Cox, B.E. Young, A.S.L. Rodrigues, D.L.
Fischman, and R.W. Waller. 2004. Status and trends of amphibian declines and
extinctions worldwide. Science 306:1783–1786.
Sullivan, B. 1997. Early Days on the Georgia Tidewater. The Story of McIntosh
County and Sapelo. 5th Edition. McIntosh County Board of Commissioners,
Darien, GA. 858 pp.
Thompson, W.L., G.C. White, and C. Gowan. 1998. Monitoring Vertebrate Populations.
Academic Press, San Diego, CA. 365 pp.
Tuberville, T.D., J.D. Willson, M.E. Dorcas, and J.W. Gibbons. 2005.
Herpetofaunal species richness of southeastern national parks. Southeastern
Naturalist 4:537–569.