Reptile species are declining on a global scale. Six significant threats to reptile populations are habitat loss and degradation, introduced invasive species, environmental pollution, disease, unsustainable use, and global climate change

Despite the continuing loss of wetland habitats and associated declines in amphibian populations, attempts to translate wetland losses into measurable losses to ecosystems have been lacking. We estimated the potential productivity from the amphibian community that would be compromised by the loss of a single isolated wetland that has been protected from most industrial, agricultural, and urban impacts for the past 54 years. We used a continuous drift fence at Ellenton Bay, a 10-ha freshwater wetland on the Savannah River Site, near Aiken, South Carolina (U.S.A.), to sample all amphibians for 1 year following a prolonged drought. Despite intensive agricultural use of the land surrounding Ellenton Bay prior to 1951, we documented 24 species and remarkably high numbers and biomass of juvenile amphibians (>360,000 individuals; >1,400 kg) produced during one breeding season. Anurans (17 species) were more abundant than salamanders (7 species), comprising 96.4% of individual captures. Most (95.9%) of the amphibian biomass came from 232095 individuals of a single species of anuran (southern leopard frog[Rana sphenocephala]). Our results revealed the resilience of an amphibian community to natural stressors and historical habitat alteration and the potential magnitude of biomass and energy transfer from isolated wetlands to surrounding terrestrial habitat. We attributed the postdrought success of amphibians to a combination of adult longevity (often >5 years), a reduction in predator abundance, and an abundance of larval food resources. Likewise, the increase of forest cover around Ellenton Bay from <20% in 1951 to >60% in 2001 probably contributed to the long-term persistence of amphibians at this site. Our findings provide an optimistic counterpoint to the issue of the global decline of biological diversity by demonstrating that conservation efforts can mitigate historical habitat degradation.

Recent studies suggest that freshwater turtle populations are becoming increasingly male-biased. A hypothesized cause is a greater vulnerability of female turtles to road mortality. We evaluated this hypothesis by comparing sex ratios from published and unpublished population surveys of turtles conducted on-versus offroads. Among 38 166 turtles from 157 studies reporting sex ratios, we found a consistently larger female fraction in samples from on-roads (61%) than off-roads (41%). We conclude that female turtles are indeed more likely to cross roadways than are males, which may explain recently reported skewed sex ratios near roadways and signify eventual population declines as females are differentially eliminated.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Society for the Study of Amphibians and Reptiles is collaborating with JSTOR to digitize, preserve and extend access to Journal of Herpetology.ABSTRACT.-A major drought in South Carolina provided opportunity to observe certain reproductive and emigration responses of freshwater turtle populations that have been studied for 15 years. Five species responded differentially to the drying of a major aquatic habitat. Pseudemys scripta and P. floridana emigrated in greater numbers, and fewer females laid eggs than in any previous year. Sternotherus odoratus and Deirochelys reticularia did not reproduce at the level of previous years but did not abandon the aquatic habitat. Reproduction and emigration of Kinosternon subrubrum were not appreciably different from other years. The differing responses of the species are discussed in terms of the ecological and evolutionary differences between them.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.ABSTRACT: Standing crop biomass of freshwater turtles and minimum annual biomass of egg production were calculated for marsh and farm pond habitats in South Carolina and in Michigan. The species in South Carolina included Chelydra serpentina, Deirochelys reticularia, Kinosternon subrubrum, Pseudemysfloridana, P scripta and Sternotherus odoratus. The species in Michigan were Chelydra serpentina, Chrysemys picta and Emydoidea blandingi. Biomass was also determined for a single species population of P scripta on a barrier island near Charleston, South Carolina.Population density and biomass of Pseudemys scripta in Greene Pond on Capers Island were higher than densities and biomass of the entire six-species community studied on the mainland. In both the farm pond and marsh habitat in South Carolina P scripta was the numerically dominant species and had the highest biomass. In Michigan, Chrysemys picta was the numerically dominant species; however, the biomass of Chelydra serpentina was higher. The three-species community in Michigan in two marshes (58 kg ha-1 and 46 kg ha-1) and farm ponds (23 kg ha71) had lower biomasses than did the six-species community in a South Carolina marsh (73 kg-1). Minimum annual egg production by all species in South Carolina averaged 1.93 kg had1 and in Michigan averaged 2.89 kg ha-1 of marsh.

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Eggs of the chicken turtle (Deirochelys reticularia) were collected in South Carolina from clutches laid in the spring and fall. Clutch size averaged 8.0 eggs (2 SE = 1.6; n = 15) and was weakly correlated with body size of the female. Wet mass of the clutch averaged 72.4 g (2 SE = 11.6, n = 15). There were no significant differences in clutch size or wet mass between spring and fall nesting seasons. Individual eggs laid in the fall (° = 10.7 g) were significantly larger than those laid in the spring (° = 8.5 g). Fifteen eggs laid in the spring and incubated at 29° ± 2°C averaged 152 d to hatching. Hatchling plastron length averaged 24.3 mm, and body wet mass was 6.7 g. Hatchlings (dry mass) contained 27.4% lipid, and the lipids remaining in the neonate at hatching represented 61% of the lipids originally present in the egg. The wet mass of hatchling is highly correlated with wet mass of the egg. In contrast to clutch size, egg size had a strong positive relationship to body size. A morphological constraint, the width of the pelvic canal, is proposed as having an influence on this relationship. The negative relationship between an optimized egg size and clutch size was not evident, so current optimality models do not appear to be applicable to Deirochelys.

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