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    ASIH Stoye Award, Herpetology II (Conservation, Ecology and Ethology)

    2021-07-22   09:15 - 11:45

    Moderator: Chris Beachy

    1.  09:15  IN-PERSON    Improving Detection of Dusky Gopher Frog (Ranasevosa) Advertisement Calls. Sara Rivera*, Biology Department, Western Carolina University; Joseph Pechmann, Biology Department, Western Carolina University; Jonathan Micancin, Biology Department, Young Harris College; Jaime Smith, Biology Department, Western Carolina University; John Tupy, U.S. Fish and Wildlife Service; James Lee, The Nature Conservancy

    The Dusky Gopher Frog, Rana sevosa, is a critically endangered species found in southern Mississippi and the subject of multiple conservation efforts. These include establishing new populations by translocation of captive-reared young to restored habitat, which requires monitoring of translocation success. Monitoring can be effectively done through detection of the frog’s conspicuous mating calls. Most frog species call above the water, which makes it easy to hear them in person and in automated recordings made using aerial microphones placed near ponds. However, R. sevosa sometimes call underwater, which makes their detection difficult. To better detect underwater calling, we paired hydrophones (underwater microphones) with aerial microphones and deployed them at dusky gopher frog breeding ponds. Compared to in air, sound travels more effectively in water and experiences less interference from background noise. Assuming equal calling above and below water, we hypothesized that the hydrophones should detect more calls than the aerial microphones. We made recordings ranging from 3-5 minutes at thirty-minute intervals every night during the frog breeding season (typically December-March) from 2012 to 2019 at five frog breeding ponds. The hydrophone recordings contained more calls than recordings from aerial microphones. By determining the more effective acoustic tool, we hope to improve monitoring of existing populations and translocation success to ensure the survival of this species into an uncertain future.

    2.  09:30  VIRTUAL    Quantifying Southern Pacific Rattlesnake (Crotalus oreganus helleri) Hunting Behavior Through Community Science. Emily Urquidi*, California State University San Bernardino; Breanna Putman, California State University San Bernardino

    Rapid environmental changes are affecting organisms worldwide. It is increasingly important to study animal behaviors as these are the first responses organisms can mount against environmental changes. However, top-level predators can be difficult to study in completely natural environments because of the time and costs associated with tracking most of these animals. Rattlesnakes, in particular, are threatened by habitat loss and human activity, and even though they are often abundant, they require costly tracking for researchers to quantify the behaviors of wild individuals.The use of community science could decrease such costs by increasing access to large crowd-sourced datasets across broad temporal and spatial scales. Our study focused primarily on Southern Pacific Rattlesnakes which are hard to study due to their cryptic ambush hunting method.We utilized two community science platforms, iNaturalist and HerpMapper, to study the hunting behaviors of wild rattlesnakes. Using 220 observation photos, we quantified the direction of the hunting coil (i.e. “handedness”), microhabitat use, and age of the snake. With these data, we looked at whether snakes exhibited an ontogenetic shift in behaviors.We found no differences between adults and juveniles in coil direction. Age, however, had an effect of microhabitat use, with adults using brush microhabitats more than juveniles, while juveniles used dirt microhabitats more than adults. We also found that juveniles were most commonly observed during the spring, while adults were more consistently observed throughout the year. Overall, our study shows the promise of using community science to study the behaviors of cryptic predators.

    3.  09:45  IN-PERSON    Modeling Mojave Desert Tortoise Movement Behavior for Inference on Anthropogenic Disturbances. Steven Hromada*, University of Nevada, Reno; Todd C. Esque, United States Geological Survey; Amy G. Vandergast, United States Geological Survey; Kenneth E. Nussear, University of Nevada, Reno

    Describing how animal movements are influenced by landscape features is important to understanding a species’ ecology and how anthropogenic disturbance may alter species movements, dispersal, and ultimately connectivity among populations. The Mojave desert tortoise is a threatened species that often interacts with human infrastructure within its habitat. We studied tortoise movements using GPS loggers recording hourly locations at multiple sites in the Mojave Desert of Nevada and California. Tortoises at our sites interacted with a variety of human infrastructure including paved roads, dirt roads, and fences. Hidden Markov models allow for the characterization of animal movement behavior from fine-scale telemetry data by categorizing data into ‘states’ that represent different behaviors based on parameters of the movement trajectory. We fit two-state hidden Markov models to our GPS logger data to make inferences on how tortoise movement behavior relates to anthropogenic and natural features. Our results quantified relationships between tortoise movement behavior and temporal and environmental covariates. We found that temporal covariates alone best explained state transition probability: tortoises were more likely to transition from the encamped state to the moving state during daylight hours, though this probability decreased throughout the year. We also demonstrated a relationship between tortoise movement behavior and environmental covariates. For example, tortoises took longer movements in washes and farther away from paved roads. Our findings support how this method can better describe the relationship between tortoise movement behavior and natural and anthropogenic features.

    4.  10:00  IN-PERSON    Biochemical Warfare: coevolution of venom and venom resistance among rattlesnake predators and their mammal prey. Kelly Robinson*, San Diego State University; Matthew Holding, University of Nevada-Reno; Malachi Whitford, San Diego State University; Anthony Saviola, The Scripps Research Institute; John Yates, The Scripps Research Institute; Rulon Clark, San Diego State University

    Predator-prey interactions often lead to the coevolution of adaptations associated with avoiding predation and, for predators, overcoming those defenses. Antagonistic coevolutionary relationships are often not simple interactions between a single predator and prey but rather a complex web of interactions between multiple coexisting species. Coevolution between venomous rattlesnakes and small mammals has led to physiological venom resistance in several mammalian taxa. In general, viperid venoms contain large quantities of snake venom metalloproteinase toxins (SVMPs), which are inactivated by SVMP inhibitors expressed in resistant mammals. We explored variation in venom chemistry, SVMP expression, and SVMP resistance across four co-distributed species (California Ground Squirrels, Bryant’s Woodrats, Southern Pacific Rattlesnakes, and Red Diamond Rattlesnakes) collected from four different populations in Southern California. Our aim was to understand phenotypic and functional variation in venom and venom resistance in order to compare coevolutionary dynamics of a system involving two sympatric predator-prey pairs to past studies that have focused on single pairs. Proteomic analysis of venoms indicated that these rattlesnakes express different venom phenotypes when in sympatry. Our results also indicate variation in venom resistance between mammal species and sites, with snakes from one geographic site expressing SVMPs to which few mammals were resistant. Additionally, we found that Red Diamond venom, rather than woodrat resistance, was locally adapted. Our findings highlight the complexity of coevolutionary relationships between multiple predators and prey that exhibit similar offensive and defensive strategies in sympatry.

    5.  10:45  VIRTUAL    Distribution, occupancy, and habitat associations of grassland-associated reptiles and amphibians in Northwest Arkansas. Ethan Royal*, University of Arkansas; Chelsea Kross, Illinois Natural History Survey; J.D. Willson, University of Arkansas

    Grasslands historically covered much of inland North America, and many species have adapted to the unique conditions found in grassland ecosystems, including fourteen reptile and amphibian species of conservation concern in Arkansas. Less than 1% of grassland habitat remains in Arkansas, with much historic grassland having been converted for urban and agricultural development, resulting in steep population declines for many grassland-associated species. We assessed the state of herpetofaunal communities in intact grassland habitat, as well in degraded and developed historic grassland habitat throughout Northwest Arkansas. We performed vegetation surveys and repeated, low intensity herpetofauna surveys at 34 sites encompassing a range of grassland site types and management regimes. We quantified landscape characteristics representing land use, topographic variation, soil composition, and vegetative communities and analyzed the effects of these landscape characteristics and local vegetative conditions on herpetofaunal assemblages using hierarchical Bayesian community occupancy modeling. We recorded 55 reptile and amphibian species, including eight grassland-associated species of conservation concern in Arkansas. Vegetation conditions differed among sites representing degraded prairie, managed prairie, and forested habitat, although these differences were represented in broad strokes and there was considerable overlap among sites across groups. Herpetofaunal species richness and species-specific occupancy were influenced by both landscape-level and local habitat variables, but responses to specific variables varied widely among species. Because species-specific responses to variables differed greatly, even among grassland-associated species, we emphasize the importance of developing clear management goals that aim to create appropriate species-specific habitat conditions within a species’ historical distribution.

    7.  11:15  VIRTUAL    Interactions Between a State Threatened Turtle Species and an Invasive Bivalve. Anna Kase*, University of South Dakota; Vanessa Weigel, University of South Dakota; Danielle Galvin, University of South Dakota; Jacob Kerby, University of South Dakota

    Zebra Mussels (Dreissena polymorpha) are an invasive mussel species that have spread across most of the U.S. and were first found in South Dakota in 2015 in the lower part of the Missouri River. In 2019, Zebra Mussels were detected in a northern Missouri River reservoir, Lake Sharpe, for the first time. To determine how Zebra Mussel presence impacts native wildlife, we examined whether or not the South Dakota state threatened False Map Turtle (Graptemys pseudogeographica) would consume Zebra Mussels in a laboratory setting. False Map Turtles were collected from a historically invaded site on the Missouri River (n=25) and a recently invaded site (n=23). Turtles were presented with five snails and five mussels of three size classes for 24 hours. Zebra Mussel consumption was analyzed using a Bayesian generalized linear model. We found an average probability of 96.7% that small mussels were consumed more often than medium or large mussels. There was no support that more experienced turtles from the historically invaded site consumed more total mussels than turtles from the recently invaded site (56.2% probability). These results demonstrate turtles’ readiness to consume mussels regardless if they had previously been in contact with the mussels and a general propensity to consume small mussels. Ecologically, these attributes of Zebra Mussel consumption by False Map Turtles could help quell initial invasions through overall consumption regardless of experience and by consuming more small immature mussels before they have a chance to breed.

    8.  11:30  VIRTUAL    Signaling in an Urbanized World: A Study on Ventral Patch Size and Symmetry in Western Fence Lizards. Nina Fresco*, California State University San Bernardino; Bree Putman, California State University San Bernardino

    As the human population grows, so does the development of urban areas. Urban areas are knownto have a poorer quality habitat for animals, which can induce stress. This stressful environment can affect the development of animal traits, including visual signals used for intraspecific communication. In this study, we focused on the size and symmetry of the signaling patches in the Western Fence Lizards (Sceloporus occidentalis) in rural and urban habitats in Southern California. Photographs of lizards were taken, and we used ImageJ to quantify the areas of the throat and belly patches and to count the number of scales that make up each patch. We did this for both males and females. We hypothesized that Western Fence Lizards will exhibit smaller and more asymmetrical patches in urban areas because they experience more stress in these habitats. This is important because this can show developmental issues associated with urbanization, alter- ing species’ ability to coexist with humans in an increasingly urban world. We found that urban lizards have bigger throat patches than lizards found in natural habitats. Male lizards have bigger throat patches than females. The lizards found in the Claremont site had larger relative belly patches than the San Bernardino site. We also found that there was more belly patch asymmetry in the natural lizards.

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