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    Session 25: SSAR Seibert Conservation (first 5)/ Seibert Physiology/Morphology (last 5)

    Room: Ballroom 111A

    2022-07-29   13:30 - 16:00

    Moderator: Dave Blackburn



    1.  13:30  Sneaky Snakes: Detection and Occupancy of Sympatric Watersnakes (Colubridae: Nerodia) in the Brazos River Watershed, Texas. Jessica Yates*, Stephen F. Austin State University; Stephen Mullin, Stephen F. Austin State University   yatesjr1@jacks.sfasu.edu

    Habitat alterations adjacent to wetlands disproportionately impact semiaquatic snakes because of their reliance on both terrestrial and aquatic habitats. Brazos River Watersnakes, Nerodia harteri, are endemic natricines with one of the most restricted geographic ranges in North America. To identify what habitat and/or environmental conditions favor snake presence and determine how much search effort should be expended to declare N. harteri absent from a site, we quantified detection and site occupancy probabilities of N. harteri and its sympatric congeners (N. erythrogaster and N. rhombifer). We established 15 transects, all at sites where N. harteri had been previously documented. We surveyed each of these sites 8 times from 2020-2021, and at least 2 people searched for snakes during each visit. The likelihood of detecting N. harteri was positively correlated with the amount of search effort. Detection probabilities for N. erythrogaster and N. rhombifer were associated with environmental conditions such as humidity and ambient temperature, whereas the probabilities of occupancy for either of these species increased with higher availability of in-stream riffle habitat. Our results indicate the sympatric Nerodia spp. are utilizing different features of their habitat and their activity patterns are associated with different environmental conditions. To better understand habitat use and niche partitioning of these sympatric Nerodia spp., long-term monitoring is needed, and habitat management — such as the preservation of riffle habitat — might be necessary to minimize the risk of resource limitation and competitive displacement.


    2.  13:45  Informing the Mantella cowaniiAction Plan. Devin Edmonds*, University of Illinois at Urbana-Champaign; Raphali Andriantsimanarilafy, Madagasikara Voakajy   dae2@illinois.edu

    Madagascar is an amphibian diversity hotspot with remarkable species richness and endemism. Of the more than 370 endemic frog species on the island, Mantella cowanii is one of the most threatened. The species is restricted to four isolated locations in the central highlands where almost no forested habitat remains. Ongoing mining and bushfires continue to threaten populations. The Malagasy government, biodiversity conservation NGOs, and local communities collaboratively launched a conservation action plan late last year to prevent further declines. Our doctoral work fills the research needs of the action plan, and we report here on preliminary results from the first field season during November 2021 to March 2022. We verified species presence at three of four localities and collected tissue samples from 31 individuals for genetic analyses. We estimated abundance for two populations and compared results to those obtained from count data using capture-mark-recapture methods and a closed population model. Additionally, we studied habitat use and behavior in one population near Antoetra to help develop a future ex situ conservation program. Next field season, we will continue research activities, emphasizing building local capacity to monitor M. cowanii populations long-term.


    3.  14:00  IMPACT OF HUMAN-SNAKES CONFLICT THROUGH CULTURAL AND RELIGIOUS BELIEFS ON ENVIRONMENT IN RWANDA. Oscar Umwanzisiwemuremyi*, Institut Pertanian Bogor   muremyioscar@yahoo.fr

    Rwanda like other African countries has beautiful flora and fauna which are allocated in Forests, land, rivers, and lakes. As the country affected by Genocide against Tutsi in 1994 ended up by loss of biodiversity. For that reason Rwanda lined ecosystem conservation to protect biodiversity and environment. But in Rwandan society, snakes are considered as bad living organisms due to cultural rituals and mentalities which were adopted by witch doctors and old people. In addition there was Christianity’s belief introduced at the end of 19 century with white fathers. For example many priests and pastors taught their Christians that snakes are evils or ghosts by using bible verses like Genesis 3: 13-15. All these aforementioned causes were worsening human–snake conflicts by increasing number of killed snakes and even today these false narratives are still in place across the country and Africa. As result Rwanda and Africa are experienced loss snakes which are affecting biodiversity chain and impacted our environment. To advocate this, Rwanda through Rwanda cultural heritage has exhibited live snake in museum since 2013 for educate people about snakes and its conservation. During my working experience over 7years, I have overseen that many visitors were having similar beliefs. Also I discovered a lot of untold good behaviors about snakes which needs to be addressed countryside and through continent in order to reduce human-snake conflict and its effects on our environment. This must be addressed on national and international level through different channels and organizations supports.


    4.  14:15  Evaluating the Efficacy of Environmental DNA Sampling for Two Cryptic Species of Torrent Salamanders. christopher cousins*, Oregon State University; Lindsey Thurman, USGS; Jennifer Allen, Oregon State University; Dede Olson, USFS; Brooke Penaluna, USFS; Tiffany Garcia, Oregon State University; Emily Dziedzic, Oregon State University   christopher.d.cousins@gmail.com

    As climates continue to impact ecosystems, there is an increased need to develop effective and straightforward methods to monitor species presence to monitor and track biodiversity, local extirpations, elevational shifts, and phenological responses. Novel monitoring techniques are often needed for species with unique life histories, low detection probabilities, or for threatened and endangered species. Cascade (Rhyacotriton cascadae) and Columbia torrent salamanders (Rhyacotriton kezeri) are stream-associated amphibians endemic to the Pacific Northwest and are candidate species for listing under the United States Endangered Species Act. In 2019, we performed simultaneous physical and eDNA surveys in 12 stream sites per species across the entirety of their ranges. We developed species specific assays and used quantitative PCR (qPCR) to determine if eDNA was an appropriate survey method relative to physical surveys. We used Bayesian hierarchical models to determine the relationships between detection probability and site conditions at the site, sample, and PCR replicate levels. We successfully detected R. kezeri at every site where we detected salamanders with physical surveys, and detected R.cascadae at ten of twelve sites with physical detections. We found relationships between both biotic and abiotic site conditions on detection probabilities, suggesting that site conditions may impact the effectiveness of eDNA monitoring. Our work provides a noninvasive passive sampling method for aquatic salamanders that can be used for future monitoring work and inform managers of shifts in persistence, and principles for best use.


    5.  14:30  Assessing Climate Change Vulnerability of Amphibians in the North-Central U.S. Ross Hinderer*, University of Montana; Lisa Eby, University of Montana   rkhinderer@gmail.com

    Climate change is one of the most important threats to biodiversity worldwide, including for amphibians. Climate change vulnerability assessment (CCVA) is a technique to integrate species-specific relative risks associated with climate changes, using characteristics such as their habitat associations or life-history traits to inform the assessment. Although CCVA has been performed for amphibians at very broad scales, management actions typically occur at the regional or state level. We performed a CCVA for amphibians of the North-Central United States, focusing on aquatic-breeding species that are listed as Species of Greatest Conservation Need (SGCN). Many amphibian species are lacking in life history information, so we based our CCVA on applying life history theory to basic characteristics that were more readily available and reliable and thought to influence climate change vulnerabilities (e.g., clutch size, primary breeding habitat). We combined trait metrics with measures of climate change exposure to develop a relative vulnerability ranking of the SGCN species in each state and across the region. For example, of the thirteen SGCN in Kansas, spring peepers (Pseudacris crucifer) were the most climate change-exposed and relatively vulnerable, even though the species is broadly distributed and apparently secure across much of the eastern USA. Results from state-level CCVAs can give a clearer picture of the local risks faced by species and provide wildlife managers another way to prioritize management actions to mitigate threats from climate change.


    6.  14:45  Sweating it Out in the Sauna: Heat and Humidity Increase Cutaneous Evaporative Water Loss in Lizards. Savannah Weaver*, California Polytechnic State University; Tess McIntyre, California Polytechnic State University; Taylor Van Rossum, California Polytechnic State University; Emily Taylor, California Polytechnic State University   savannahjweaver@gmail.com

    The skin is the main interface between an organism and environmental stressors. Cutaneous evaporative water loss (CEWL) can help organisms thermoregulate but can also lead to dehydration. We investigated whether CEWL (water evaporation across the skin) and plasma osmolality (a proxy for dehydration) change in response to environmental humidity and temperature. Temperature varies widely in many ecosystems, while changes in humidity are more stable and linked to water availability, so we hypothesized that humidity impacts osmoregulation more than temperature. To assess this, we acclimated Western Fence Lizards (Sceloporus occidentalis) to one of four climate treatments: hot-humid, cool-humid, hot-dry, or cool-dry. We found that humid-acclimated lizards significantly increased CEWL at 3-5x the rate of dry-acclimated lizards, indicating that humidity is more influential for CEWL than temperature, which had a comparably small effect. For plasma osmolality, temperature is the more influential variable. Hot-dry-acclimated lizards had the greatest increase in plasma osmolality, followed by hot-humid, while cool-acclimated lizards showed decreased plasma osmolality. Our results indicate that S. occidentalis have a strong osmoregulatory response to their environment, with significant temperature and humidity-modulated changes in both water loss and hydration within only eight days of acclimation. As global temperatures rise and drought intensifies, our results will inform conservation management and inspire future studies investigating the mechanisms behind the results observed.


    7.  15:00  Atrazine and amphibians: Atrazine’s impacts on neurodevelopment and behavior in an anuran model. Janniry Cabrera Belen*, Moravian University; Sara McClelland, Moravian University   janniry9@gmail.com

    Amphibians are one of the most endangered classes of the Animal Kingdom. However, a lack of amphibian research has resulted in a disparity of data to address their decline. Pesticides contribute to this decline, and pose a threat to anuran health due to their permeable skin. Atrazine, a triazine herbicide, inhibits photosynthesis to hinder plant growth. In vertebrates, it is an endocrine disrupter that impacts reproductive structures, function, and behavior in amphibians. Studies have analyzed the impacts of atrazine on reproductive structures and behavior, but none have analyzed the neurodevelopmental effects of atrazine. We hypothesized that atrazine exposure during development would result in morphological changes in the brain as well in behavior. To test this hypothesis, Xenopus laevis tadpoles were exposed for three weeks to either a vehicle control or 3 ?g/L atrazine, a concentration that is considered safe by the Environmental Protection Agency (EPA). Following exposure, behavior, body morphology, and brain morphology were measured. Preliminary analysis of the data found that atrazine exposure during development increased boldness of tadpoles, spending more time in the center of a behavioral arena than controls (p< 0.001). There was also a trend that exposed tadpoles swam away from predators quicker with 85% of animals immediately responding to a tactile predator stimulus, compared to only 50% of control animals (p=0.061). Investigating whether atrazine impacts neurodevelopment and behavior will help fill a knowledge gap and may offer new insights into how freshwater vertebrates are being impacted by atrazine.


    8.  15:15  Comparison of Ovaprim and human chorionic gonadotropin on sperm parameters and weight response in Fowler’s toads (Anaxyrus fowleri). Erin Saylor*, Mississippi State University   ems727@msstate.edu

    Current amphibian assisted reproductive technologies (ART) use synthetic and non-synthetic forms of hormones from goldfish and humans, respectively, to stimulate gamete release for genetic management. To date, salmon gonadotropins have not been widely investigated for anuran sperm collection. For this study, we compared the effects of Ovaprim, which contains a synthetic form of salmon gonadotropin releasing hormone (sGnRH) and the dopamine antagonist domperidone, with the standard hormone human chorionic gonadotropin (hCG) on inducing spermiation and spermatozoa quality parameters in Fowler’s toads (Anaxyrus fowleri). Male A. fowleri were treated with either 300 µl of Ovaprim (n=15) or 300 IU hCG (n=15). Spermic urine was collected over a 24-hour time course, with toad weights taken at each time point. If there was a spermiation response to the hormone, motility and morphology of the samples were taken. Spermic response rate and the above parameters were compared between the two hormone treatments using a generalized additive model, with individual as a random effect. Results showed that sperm obtained using Ovaprim had significantly lower total motility (p<0.05) and higher rates of abnormality (p<0.05) compared to hCG. Overall, Ovaprim induced spermiation in 10/15 toads (66.6%) while hCG induced spermiation in 15/15 toads (100%). The average weight change of males administered Ovaprim and hCG were 13.9% and -4.4%, respectively. These results show that while Ovaprim does induce spermiation in Anaxyrus fowleri males, the low quality of the spermatozoa suggests that Ovaprim is not as effective for eliciting spermiation as hCG in bufonids.


    9.  15:30  A Tale of Two Radiations: Comparing Phenotypic Evolution in Australian and Malagasy Skinks. Natasha Stepanova*, University of Michigan; Daniel Rabosky, University of Michigan   nstepanova@berkeley.edu

    Radiations of closely related species in different biogeographic regions may show similar macroevolutionary patterns if the clades respond predictably to a common adaptive landscape. Conversely, evolutionary trajectories may diverge if outcomes are shaped more by unique historical or eco-geographic factors. In this study, we compared the dynamics of phenotypic evolution in scincid lizards from Australia and Madagascar to test the relative importance of determinism and contingency. Australian sphenomorphines form an impressive radiation (>250 sp.), with the majority of their diversity concentrated in the genera Ctenotus and Lerista. They are diverse in their morphology, with limb-reduced, elongate forms having evolved multiple times. In Madagascar, a radiation of scincines (>60 sp.) has resulted in many morphotypes superficially similar to Australian sphenomorphines. We tested how these radiations fill out morphospace, whether these forms have evolved through similar evolutionary pathways, and how these morphotypes fill out ecological and geographic space. To answer these questions, we used CT scans of >140 species, encompassing the phylogenetic and morphological diversity of these groups. We took linear measurements of the skull, limbs, girdles, and body, and used multivariate comparative methods to compare the tempo and mode of phenotypic evolution. Broadly these two radiations occupy similar regions of morphospace, with limb traits forming the major axes of morphological differentiation. However, they differ in their relative density of morphospace occupation. Despite variation in their evolutionary pathways, these two radiations have reached remarkable levels of convergence. These results lend important insight into the role of contingency in convergent evolution.


    10.  15:45  Spectral Reflectance as a Thermoregulatory Mechanism inHyla Tree Frogs. Analisa Shields-Estrada*, The University of Texas at Austin; David Cannatella, The University of Texas at Austin   ashieldsestrada@utexas.edu

    Investigating patterns of ecological selection and pinpointing resulting thermoregulatory phenotypes in species most at risk of extinction, is paramount to our understanding of how species will fare in a rapidly changing climate. One important thermoregulatory phenotype is color (i.e., visible spectral reflectance). Adaptive variation in color reflects a suite of organismal specific traits and behaviors mediated by natural and sexual selection pressures. The role of color in signaling has been studied extensively, however, how color influences thermoregulation, specifically in taxa with color specific competing selection pressures, and the roles of other reflection spectra (i.e., the near infrared), have been largely ignored. Our work examines the adaptive role of visible and near-infrared spectral reflectance in tree frog (Genus Hyla) thermoregulation. We used ecophysiology experiments to measure water loss and warming tolerance of three species of hylids inhabiting diverse microclimates across Texas and took spectral reflectance measurements in the visible (400-700nm) and near-infrared spectra (700-1100nm) to assess how spectral reflectance mediates thermoregulatory ability in these frogs. Our results point to microhabitat specific inter-populational variation in thermoregulatory ability among Hyla. We also determined that some frogs use changes in spectral reflectance to regulate body temperature and thereby increase thermoregulatory ability through increased reflectance. This work provides evidence for unique thermoregulatory mechanisms in tree frogs and highlights the importance of identifying traits key to species persistence in an increasingly changing and unpredictable climate.




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