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    V: Amphibian Conservation and Ecology II

    2021-07-26   13:30 - 14:45

    Moderator: Angela Burrow

    1.  13:30  VIRTUAL    Ground Cover and Native Ant Predation Influence Survival of Metamorphic Amphibians in a Southeastern Pine Savanna Undergoing Restoration. Angela Burrow*, University of Georgia; Brian Crawford, University of Georgia; John Maerz, University of Georgia

    Longleaf pine savannas historically supported abundant ground cover maintained by frequent fire but little other disturbance. Ground cover creates microclimates with lower temperatures, higher humidity, and increased soil moisture that may benefit wildlife, particularly small vertebrates such as amphibians. Today, most historical pine savannas have had extensive soil disturbance and altered fire regimes resulting in reduced ground cover and altered soil fauna communities including predatory invertebrates. We used a factorial terrestrial cage study to test the effects of native wiregrass (Aristida spp.) cover and the exclusion of a native predatory ant (Dorymyrmex smithi) on the survival of post metamorphic Ornate chorus frogs (Pseudacris ornata) and Gopher frogs (Rana capito). Although we were unable to achieve full ant exclusion, ant reduction in exclusion treatments and plant cover had an interactive effect on metamorph survival. Ant exclusion tended to increase Gopher frog survival and this effect was more pronounced when wiregrass was present. Within ant treatments, survival of Gopher frogs increased slightly with increasing wiregrass cover. Ornate chorus frogs had a high probability of survival (>95%) in all ant exclusion treatments regardless of wiregrass cover; however, in treatments without ant exclusion, survival increased with increasing wiregrass cover. Our results demonstrate that high abundances of a native ant species and low coverage of native wiregrass, which are legacies of historical soil disturbance and altered fire regimes, interact to elevate mortality of juvenile amphibians. Minimizing soil disturbance and restoring native ground cover are likely important for amphibian habitat management within historical southeastern pine savannas.

    2.  13:45  VIRTUAL    Utilizing Partnerships to Create Breeding Habitat for California Red-legged Frogs. Emmeleia Nix*, Bureau of Land Management; Michael Westphal, Bureau of Land Management

    Loss of natural breeding habitat is a primary threat to the California red-legged frog,Rana draytonii. Cotoni-Coast Dairies National Monument (CCDNM), on the coast of the San Francisco Peninsula, is in the portfolio of Federally-managed habitat forR. draytoniiand provides promising conservation opportunities. The coastal estuaries on the property have been historically degraded to create passage for a railroad and Highway One, and consequently the sole breeding habitat forR. draytoniiat CCDNM is in artificial ponds, many of which are failing. The US Bureau of Land Management, PG&E, the Santa Cruz Resource Conservation District and the US Fish & Wildlife Service formed a partnership to create large, shallow oxbow pools parallel to a major creek on CCDNM. Approximately $75,000 was budgeted for construction, which took 2 weeks to complete. The resultant ponds filled successfully and remained filled through the subsequent 2-year monitoring period. In the summer of 2019, adultR. draytoniicolonized the ponds and in the spring of 2020 the first tadpole was found. This project exemplifies the use of agency partnerships to create critical habitat for imperiled species.

    3.  14:00  VIRTUAL    Toad Smoke: (Un)Natural History of the Sonoran Desert Toad. Robert A. Villa*, The Desert Laboratory, University of Arizona

    The ethno-herpetology and conservation of the Sonoran Desert Toad (Incilius alvarius), is presented in light of the historic and revived demand from the psychedelic pharmacopeia.

    5.  14:15  VIRTUAL    Incubation Temperature and Maternal Effects on Thermal Physiology in Ambystoma mexicanum. Regina Spranger*, UC Santa Cruz; Barry Sinervo, UC Santa Cruz

    Endemic organisms, especially aquatic species with no ability to migrate, face extreme effects from climate change. One possible escape route is via maternal effects, but little is known about how amphibian mothers influence their offspring’s' thermal traits. Facing thermal stress, a mother may program her progeny to cope with higher temperatures in the next generation, and then we would see between-generation plasticity. We study how Mexican Axolotl, Ambystoma mexicanum, mothers’ might influence their offspring’s thermal physiology through between-generation plasticity and incubation temperature. I genetically crossed A. mexicanum in a half-sibling design by pairing males with females from 18 and 21 C treatments to measure effects on progeny’s thermal preference and critical thermal maximum. I measure maternal effect-driven plasticity among full-siblings from dams, while half-siblings are used to estimate additive genetic effects. Eggs were divided among 18 and 21 C treatments to measure effects of incubation temperature. We ran the offspring through thermal preference trials at 5 and 19 days old, and after dividing in a block design, at 33 days old, and then performed critical thermal maximum trials. Our preliminary results show that incubation temperature and mother’s temperature affect offspring thermal preference. If between-generation acclimation can occur, it could be a potential mechanism to rescue ectotherms from climate warming.

    6.  14:30  VIRTUAL    Urban Microhabitats Provide Thermal Refugia for Terrestrial Salamanders. Mia Forsline*, Occidental College; Amanda Zellmer, Occidental College

    Urban habitats are rapidly growing ecosystems all around the world, leading to unprecedented landscape changes and climate phenomena such as the urban heat island effect. While many studies have documented the intersection of urbanization and global climate change, few have studied how urbanization impacts climate at extremely small spatial scales. Therefore, this study focused on thermal trends in the microhabitats of the black-bellied slender salamander (Batrachoseps nigriventris), a lungless terrestrial amphibian sensitive to climate shifts and found in both urban and rural areas in Los Angeles, CA. We used miniature environmental sensors and an infrared thermometer to collect thermal data from December 2018 to April 2021. We sought specimens in microhabitats spanning the Los Angeles urban-to-rural gradient and measured temperature under cover objects that frequently shelter salamanders. Using remote sensing and mixed-effects models, we identified landscape factors driving changes in the microhabitat thermal profiles. Urbanization was not a primary driver of biologically significant temperature changes. Instead, we found evidence of urban cover objects acting as microrefugia by buffering broader thermal trends observed in the Los Angeles area. Future studies are needed to better our understanding of complex, micro-scale climate shifts in urban environments and improve conservation efforts for ectotherms such as salamanders.

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