Ornate Chorus Frog
© 2011 Stephen Bennett (1 of 21)
Country distribution from AmphibiaWeb's database: United States
Can you confirm these amateur observations of Pseudacris ornata?
Pseudacris ornata (Holbrook, 1836)
John B. Jensen1
1. Historical versus Current Distribution. Ornate chorus frogs (Pseudacris ornata) are restricted to the southeastern Coastal Plain (Mount, 1975) from extreme eastern Louisiana to North Carolina (Conant and Collins, 1991). Brown and Means (1984) identified the southernmost locality known as Lake County, Florida, approximately 230 km north of the incorrect southern limits illustrated on maps in Conant and Collins (1991) and Behler and King (1998). The availability of sandy soils influences the distribution of this species (Brown and Means, 1984). No substantial changes in their distribution have been noted.
2. Historical versus Current Abundance. Some authors have regarded ornate chorus frogs as common throughout their range (Wilson, 1995) or even abundant (Martof et al., 1980). Gibbons and Semlitsch (1991) reported that ornate chorus frogs are 2–3 times more abundant than southern chorus frogs (P. nigrita) at South Carolina sites studied in detail. Recently, however, there have been indications that ornate chorus frogs may be declining locally. Means and Means (2000) found that the number of breeding populations of ornate chorus frogs in the Munson Sand Hills of panhandle Florida occur in much lower densities on silvicultural lands than in nearby native habitat. They hypothesized that elimination or severe alteration of the upland habitat, resulting from intensive soil disturbance, is the principal reason. This is corroborated by a 1996–'98 rare amphibian survey conducted at 444 sites on industrial forest lands in south Georgia, south Alabama, and north Florida (Wigley et al., 1999). This study revealed that ponds where ornate chorus frogs were found had a substantially lower frequency of intensive site preparation in pond edges and surrounding upland habitats than those ponds where this species was not detected. Further, ornate chorus frogs were substantially less likely to be present if bedding had been used in primary upland stands. Therefore, it is likely that the accelerating conversion of natural pine habitats to industrial pine plantations throughout this species’ range (Dodd, 1995a) is reducing their abundance and will continue to do so without major changes in management practices. However, ornate chorus frogs are capable of reestablishing populations on abandoned agricultural lands (Brown and Means, 1984; Caldwell, 1987).
3. Life History Features.
A. Breeding. Reproduction is aquatic.
i. Breeding migrations. Ornate chorus frogs migrate from their upland retreats to aquatic sites in late fall and early winter, where they breed from November–March, depending on rains (Wright and Wright, 1949; Neill, 1957c). Behler and King (1998) report breeding activity into April. In South Carolina, peaks of immigration do not occur until January–February (Gibbons and Semlitsch, 1991). Calling males, although not indicative of breeding activity, may be heard as early as late October (Carr, 1940b; Brown and Means, 1984) and at temperatures as low as -2.8 ˚C (27 ˚F; Harper, 1937). Males arrive prior to females and begin calling, presumably to attract females to the site (Caldwell, 1987), and remain in the ponds longer than females (Caldwell, 1987). Emigration of adults from the breeding sites occurs from January–March (Gibbons and Semlitsch, 1991).
ii. Breeding habitat. Ornate chorus frogs breed in temporary wetland pools and ponds, including cypress ponds and rain-filled meadows (Harper, 1937), flooded fields and ditches (Martof et al., 1980; Caldwell, 1987), Carolina bays (Caldwell, 1987; Gibbons and Semlitsch, 1991), sinkhole ponds, and borrow pits (personal observations). Mount (1975) suggested that ornate chorus frogs are less likely to breed in shallow roadside ditches and seepage areas than other congeners, and I concur. Males usually call while sitting 2.5–25 cm (1–10 in) above the water in clumps of grass or on floating debris such as logs (Harper, 1937; Mount, 1975) or call while floating on the surface of open water (personal observations). Males often use several breeding ponds over the season (Ashton and Ashton, 1988).
i. Egg deposition sites. Egg masses are attached to submerged grass and sedge stems in shallow water areas open to full sunlight (Seyle and Trauth, 1982). Eggs hatch within 1 wk (Ashton and Ashton, 1988).
ii. Clutch size. Typically 10–100 eggs (Wright and Wright, 1949) are laid in small, loose clusters (Mount, 1975). Most of the egg masses Seyle and Trauth (1982) examined from Marion County, Georgia, contained 20–40 eggs, with a maximum of 106 in a single mass.
i. Length of larval stage. Approximately 90 d (Dundee and Rossman, 1989) in Louisiana, but ≤ 4 mo in South Carolina (Caldwell, 1987). Tadpoles may reach 43 mm TL before transformation (Dundee and Rossman, 1989).
ii. Larval requirements.
a. Food. Unknown, but tadpoles likely graze on algae.
b. Cover. Larvae are most readily found by dip-netting in submerged and emergent vegetation, suggesting they seek shelter in such cover (personal observations).
iii. Larval polymorphisms. Unknown and unlikely for this species.
iv. Features of metamorphosis. Larvae transform at 14–16 mm (Wright and Wright, 1949).
v. Post-metamorphic migrations. Newly transformed young may remain around the breeding pond to forage (Carr, 1940b) prior to emigration. Brown and Means (1984) reported the capture of 42 recently metamorphosed young 20 m from the edge of a breeding pond in late April and several young 200–370 m upslope from the pond in mid May of the same year, indicating that emigration may commence shortly after transformation. Caldwell (1987) also found that newly metamorphosed animals emigrate to the surrounding forest during late April to May.
D. Juvenile Habitat. Brown and Means (1984) found newly metamorphosed young in turkey oak (Quercus laevis) habitat on a ridge crest. Recently metamorphosed animals have been found using the refugia beneath logs and loose pieces of bark on the ground (Harper, 1937).
E. Adult Habitat. Outside of the breeding season, ornate chorus frogs are fossorial (Deckert, 1915; Carr, 1940b; Neill, 1952; Brown and Means, 1984), often burrowed among the roots of herbaceous vegetation (Deckert, 1915; Carr, 1940b; Neill, 1952). Terrestrial adult habitats include pine woodlands (Harper, 1937; Gerhardt, 1973; Martof et al., 1980), pine-oak forest (Dundee and Rossman, 1989), and fallow fields (Harper, 1937; Brown and Means, 1984; Caldwell, 1987). Habitats with sandy substrates are needed to accommodate their burrowing needs (Brown and Means, 1984). Upland retreats can be at least 425 m from the closest available breeding pond (Brown and Means, 1984). There are no data available to indicate a difference in habitats used by males and females.
F. Home Range Size. About 100 m2 (Ashton and Ashton, 1988).
G. Territories. Unknown.
H. Aestivation/Avoiding Dessication. This species remains inactive during the summer and early fall. However, heavy rains will bring them to the surface at any time, despite the temperature (Carr, 1940b).
I. Seasonal Migrations. See “Breeding migrations" above.
J. Torpor (Hibernation). Ornate chorus frogs breed during winter (Wright and Wright, 1949; Neill, 1957c), therefore hibernation does not occur. In fact, they may bask in the sun even when snow is on the ground (Ashton and Ashton, 1988).
K. Interspecific Associations/Exclusions. Ornate chorus frogs often call in association with southern chorus frogs (P. nigrita), little grass frogs (P. ocularis), spring peepers (P. crucifer), and southern leopard frogs (Rana sphenocephala; Harper, 1937). Ornate chorus frogs may also be found in breeding aggregations of eastern spadefoot toads (Scaphiopus holbrookii; Harper, 1937; Neill, 1957c) and gopher frogs (Rana capito; personal observations).
L. Age/Size at Reproductive Maturity. Males range from 25–35 mm SVL and females from 28–36 mm (Wright and Wright, 1949), although working in South Carolina, Gibbons and Semlitsch (1991) report males reach 39 mm; females, 40 mm.
M. Longevity. Most adults in natural habitats rarely live beyond their second breeding season due to predation and intraspecific fighting, although they may live 3.5 yr in captivity (Caldwell, 1987).
N. Feeding Behavior. Adults feed primarily upon small insects (Wilson, 1995). Brown and Means (1984) suggested that earthworms, nematodes, and certain insect larvae may be attracted to the root masses in which ornate chorus frogs often burrow, providing a potential food source. Further, the above-ground portions of the plants attract other insects that may be consumed by ornate chorus frogs positioned at the mouth of their burrows. Newly transformed ornate chorus frogs feed on nymphal orthopterans around the breeding ponds (Carr, 1940b).
O. Predators. Salamander larvae, including tiger salamanders (Ambystoma tigrinum), dragonfly naiads, and other aquatic invertebrates may be important predators of ornate chorus frog tadpoles (Caldwell, 1987). Neill (1952) reported the predation of an adult ornate chorus frog by a southern hog-nosed snake (Heterodon simus).
P. Anti-Predator Mechanisms. Blouin (1989) suggested that the extreme color polymorphism displayed by ornate chorus frogs is maintained through direct selection by visually oriented predators. One author reported that ornate chorus frogs make immense leaps when pursued (Holbrook, cited in Wright and Wright, 1949), while another observed that this species lies flat against the ground when surprised (Ashton and Ashton, 1988). Their habit of burrowing among the roots of herbaceous vegetation (Deckert, 1915; Carr, 1940b; Neill, 1952) may provide protection from certain predators (Brown and Means, 1984). Harper (1937) suggested that a mid winter breeding season may avoid predation by water snakes.
Q. Diseases. Unknown.
R. Parasites. Unknown.
4. Conservation. No substantial change in the distribution of ornate chorus frogs has been noted, however there are indications that populations may be locally declining (see "Historical versus Current Abundance" above) . Means and Means (2000) hypothesized that elimination or severe alteration of the upland habitat, resulting from intensive soil disturbance, is the principal reason. It is likely that the accelerating conversion of natural pine habitats to industrial pine plantations throughout this species’ range (Dodd, 1995a; Wigley et al., 1999) is reducing their abundance and will continue to do so without major changes in management practices. Ornate chorus frogs are capable of reestablishing populations on abandoned agricultural lands (see "Historical versus Current Abundance" above). This species is not protected by either state or federal regulations.
1John B. Jensen
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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