Southwest Florida Amphibian Ecology
Reprinted
from: Donnelly, M.A. 1997.
A preliminary survey of amphibians in isolated wetlands.
Pages 1-46 in S. Mortellaro,
Inventory of freshwater biota, South Florida Water Management District’s
isolated wetlands monitoring program. South
Florida Water Management District.
INDICATOR SPECIES OF HYDROLOGIC CHANGE
With the exception of two species of amphibians characterized by direct
development (Plethodon glutinosus and Eleutherodactylus
planirostris), all amphibian species listed in table 1 would be indicators
of hydrologic change because all of them are dependent on water or very wet
habitats for successful reproduction. The
two amphibians with direct development deposit eggs in terrestrial sites and
these eggs hatch as miniature adults. Most of the amphibian species found in countries of interest
to the South Florida Water Management District have a complex life cycle wherein
eggs are deposited in water (either attached to submerged vegetation, on the
surface, or in mud nests), eggs hatch into a larva, the larva undergoes
metamorphosis, and enters the terrestrial ecosystem. Exceptions to this include the aforementioned direct
developing forms, and totally aquatic forms (sirens, dwarf sirens, and amphiumas).
There are no published reports specific for the counties of interest, but
based on statewide records, I constructed one summary sheet and three figures
(figure 1, figure 2, and figure 3): calling phenology for anuran species, time
to metamorphosis for anurans, and time to metamorphosis for salamanders.
Anuran Calling Phenology: Male anurans call to attract mates and
maintain inter-male spacing, but calling and mating activities are not
completely correlated. Many species have broader calling periods than amplectant
periods, particularly in prolonged breeding taxa. Five of the 17 species of anurans can be heard calling all
year (figure 1). Scaphiopus holbrooki can call in any month of the year following
periods of heavy rainfall. These
intense storms cause S. holbrooki to
leave their burrows, mate explosively, and the tadpoles complete metamorphosis
in 10 days. Two native hylids, Acris
gryllus and Pseudacris ocularis, and the exotic Osteopilus septentrionalis can also be heard calling in any month of
the year. Rana sphenocephala also calls year round. Only two species are winter breeders (Pseudacris nigrita and Rana
catesbeiana). The remaining 10
species begin calling in the spring and continue calling through the summer.
Time to Metamorphosis - Anurans: Time to metamorphosis is
available for all 17 species of anurans that occur in counties of interest (see
figure 2: BQ = Bufo quercicus, BT = B.
terrestris, AG = Acris
gryllus, HC = Hyla Cinerea, HF =
H. femoralis, HG = J. gratiosa, HS = H. squirella,
PO = Pseudacris ocularis, PN = P. nigrita,
GC =
Gastrophryne carolinensis,
SH = Scaphiopus holbrooki, RC = Rana
capito, Rcat = R. catesbeiana, RG
= R. grylio, RS = R. Sphenocephala, EP = Eleutherodactylus
planirostris, OS = Osteopilus
septentrionalis). Two ranid
species, Rana catesbeiana and R. grylio,
take 730 and 365 days to complete metamorphosis, respectively.
Rana capito, R. sphenocephala, and Acris
gryllus can take 90 - 100 d to complete metamorphosis.
Five species take 60 days for kmetamorphosis, two take 30 days, and three
complete development in under 20 days.
Time to Metamorphosis - Salamanders: Data on time to metamorphosis
is only available for seven of the ten species known to occur in the counties of
interest (see figure 3: AT = Ambystoma
tigrinum, AM = Amphiuma means, DF
= Desmognathus fuscus, EQ = Eurycea
quadrilineata, PG = Plethodon
glutinosus, NV = Notophthalamus
viridiscens, PSA = Pseudobranchus
striatus axanthus). Two of the
seven species take more than 250 days to complete metamorphosis, two take 210
days, and three species take under 150 days.
Overall salamanders take longer to reach metamorphosis than do anurans.
Synthesis: These data are interesting because species composition
in any one wetland can indicate something about hydroperiod for any wetland.
If one were to sample a wetland and find adults and larvae of Desmognathus
fuscus, Rana sphenocephala, Rana grylio, Pseudacris nigrita, Acris gryllus,
and Pseudacris ocularis, one would categorize the wetland as having a
long hydroperiod. One would come to
this conclusion because the two ranids and the salamander require more than 200
days to complete metamorphosis. If
one were to find adults and larvae of Pseudacris
ocularis, Gastrophryne carolinensis, and Eleutherodactylus planirostris, one would conclude that the wetland
had a short hydroperiod because one species does not require water for
reproduction, and the other two frogs can complete metamorphosis in less than 50
days.
Sampling calling adults alone would not give a complete pixture about
wetland hydroperiod because most frogs and toads will call from any water body
following periods of intense rainfall. One
would want to sample larvae and non-calling population components to determine
if reproduction actually occurred. The
presence of females and juveniles would provide evidence of successful
reproduction. For example, if one
heard calls of Bufo terrestris, Rana
grylio, Osteopilus septentrionalis, Hyla cinerea, and Hyla
gratiosa, captured juvenile B. terrestris,
O. septenrionalis, and tadpoles of H. cinerea,
one would conclude that the wetland has a medium-length hydroperiod because B. terrestris, O. septentrionalis,
and H. cinerea all require at least
two months to complete metamorphosis. Even
though presence of calling Rana grylio
would suggest a long-hydroperiod wetland, the lace of larvae or juveniles would
not support that suggestion.
Species:
Bufo quercicus, Oak Toad
Family:
Bufonidae
Habitat for Reproduction:
Temporary Ponds
Calling Period:
January to October
Length of Larval Period:
30 days
Other:
Common in pine flatwoods, longleaf pine-turkey oak forests, tropical
hammocks; uncommon in xerix oak hammock, human habitats, cypress swamps
Species: Bufo
terrestris, Southern Toad
Family:
Bufonidae
Habitat for Reproduction:
All freshwater habitats
Calling Period:
March to October
Length of Larval Period:
30 - 60 days
Other: Common
in longleaf-turkey oak forests, hydric hammocks, tropical hammocks, farmlands,
human habitations, and freshwater habitats; uncommon in pine flatwoods and mesic
hammocks
Species:
Acris gryllus, Florida Cricket
Frog
Family:
Hylidae
Habitat for Reproduction:
All freshwater habitats
Calling Period:
all year
Length of Larval
Period: 41 - 90 days
Other:
Common in freshwater habitats; uncommon in pine flatwoods, mesic and
hydric hammocks and freshwater habitats
Species:
Hyla cinerea, Green Treefrog
Family:
Hylidae
Habitat for Reproduction:
Edges of ponds and lakes
Calling Period:
April to October
Length of Larval
Period: 60 days
Other:
Common in pine flatwoods, hydric hammocks, tropical hammocks, deciduous
forest, and freshwater habitats
Species:
Hyla femoralis, Pinewoods
Treefrog
Family:
Hylidae
Habitat for Reproduction:
Ponds and lakes
Calling Period:
April to October
Length of Larval
Period: 30 - 60 days
Other:
Common in pine flatwoods, longleaf pine-turkey oak forests, mesic
hammocks, deciduous forests, farmlands, freshwater habitats; uncommon in sand
pine-rosemary scrub, hydric hammocks, human habitations
Species: Hyla
gratiosa, Barking Treefrog
Family:
Hyidae
Habitat for Reproduction:
Temporary ponds
Calling Period:
April to August; may not breed annually
Length of Larval
Period: 45 - 60 days
Other:
Common near temporary ponds; uncommon in gum swamps, rare in other
habitats
Species: Hyla
squirella, Squirrel Treefrog
Family:
Hyidae
Habitat for Reproduction:
Temporary and permanent water bodies
Calling Period:
April to September
Length of Larval
Period: 25 - 55 days
Other: Common
in pine flatwoods, longleaf pine-turkey oak forests, hydric and tropical
hammocks, deciduous forests, farmlands, freshewater habitats; uncommon in sand
pine-rosemary scrub, xerix oak hammocks, mesic hammocks, and human habitations
Species: Pseudacri s nigrita, Florida Chorus Frog
Family:
Hyidae
Habitat for Reproduction:
Temporary ponds, cypress swamps, gum swamps
Calling Period:
December to March
Length of Larval
Period: 60 - 90 days
Other:
Common in pine flatwoods, farmlands, freshwater habitats; uncommon in
xeric oak hammocks
Species: Gastrophryne carolinensis, Eastern Narrow-Mouthed Toad
Family:
Microhylidae
Habitat for Reproduction:
Any freshwater habitat
Calling Period:
March to September
Length of Larval
Period: 30 days
Other:
Common in pine flatwoods, longleaf pine-turkey oak forests, exeric oak
hammocks, tropical hammocks, deciduous forests, farmlands, human habitations,
temporary ponds; uncommon in sand pine-rosemary scrub, mesic hammocks, cypress
domes
Species: Scaphiopus
holbrooki, Eastern Spadefoot Toad
Family:
Pelobatidae
Habitat for Reproduction:
Temporary ponds
Calling Period:
all year, after heavy rains
Length of Larval
Period: 10 days
Other:
Common in longleaf pine-turkey oak forests, farmlands, temporary ponds;
uncommon in xeric oak and hammocks
Species: Rana
capito, Gopher Frog
Family:
Ranidae
Habitat for Reproduction:
Cypress
heads and permanent ponds
Calling Period: January
to April
Length of Larval
Period:
100 days
Other: Commensal
with gopher tortoises; common near temporary ponds; uncommon in xeric oak
hammocks; rare in sand pine-rosemary scrub and longleaf pine-turkey forests
Species: Rana
catesbeiana, Bull Frog
Family:
Ranidae
Habitat for Reproduction:
Permanent water bodies
Calling Period:
April to September
Length of Larval
Period: 730 days
Other:
Common in freshwater habitats
Species: Rana
grylio, Pig Frog
Family:
Ranidae
Habitat for Reproduction:
Permanent water bodies
Calling Period:
April to September
Length of Larval
Period: 365 days
Other:
Common in freshwater marshes, temporary ponds, gum swamps; uncommon in
small creeks
Species: Rana
sphenocephala, Southern Leopard Frog
Family:
Ranidae
Habitat for Reproduction:
All freshwater habitats
Calling Period:
all year
Length of Larval
Period: 90 days
Other:
Common in freshwater habitats, pine flatwoods, hydric and tropical
hammocks, deciduous forest; uncommon in mesic hammocks
Species: Eleutherodactylus planirostris, Greenhouse Frog
Family:
Leptodactylidae
Habitat for Reproduction:
Terrestrial habitats
Calling Period:
April to September
Length of Larval
Period: 14 days for eggs to hatch
Other:
EXOTIC, common in sand pine-rosemary scrub, longleaf pine-turkey oak
forests, tropical hammocks, farmlands, human habitations; uncommon in mesic
hammocks; rare in xeric oak hammocks, hydric hammocks
Species: Osteopilus septenrionalis, Cuban Treefrog
Family:
Hylidae
Habitat for Reproduction:
Temporary ponds, rain pools
Calling Period:
all year
Length of Larval
Period: 60 days