P2: Herpetology: Behavior II2021-07-27 16:00 - 18:00 |
To view the posters go to https://epostersonline.com/jmih2021/. You will be able to chat one-on-one during the Tuesday poster session, the e-poster platform. |
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2. 16:00 A Review on the Autecology of Angolan Snakes. Calum Devaney*, Villanova University; Aaron Bauer, Villanova University calumdevaney@gmail.com
There are 115 species of alethinophidian snakes recorded from Angola, of which 5 are endemic. Most of the remaining taxa are broadly distributed in either Central or Southern Africa, although some are shared only with immediately contiguous countries. Data on the autecology of Angolan alethinophidians are extremely limited. Although the parity mode for nearly all has been established, information about the seasonality of reproduction and clutch/litter size is available for only 3 species based on Angolan material. Likewise, dietary data are available for only 3 species. By revisiting historical material as well as newly collected specimens we have been able to provide some autecological data for additional species, including Bitis caudalis, Crotaphopeltis hotamboeia, and Lycophidion namibianum. Clutch sizes from Angolan specimens were found to be generally smaller than those of the same species in other countries. Most species were reproductively active in the wet season. Dietary habits of Angolan snakes are consistent with those of conspecifics in more well-studied Central and Southern African countries. Overall, new data collected from Angolan snake specimens reveal intraspecific parallels in the ecology of widespread species in other parts of Africa and provide insights into the lives of understudied species in the unique environments of Angola. |
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3. 16:00 Spatiotemporal Patterns of Upland Snakes in Southern Pine Forests. Christopher Schalk*, Stephen F. Austin State University; Connor Adams, Stephen F. Austin State University; Dylan Thompson, Stephen F. Austin State University; Kasey Jobe, Stephen F. Austin State University; Krista Ward, Witchita State University; Nicholas Schiwitz, Stephen F. Austin State University; Yuhui Weng, Stephen F. Austin State University; Daniel Saenz, United States Forest Service schalkc@sfasu.edu
Central components to understanding an animal’s ecology are its habitat associations and activity patterns. Snakes possess several attributes that make assessments on their community structure particularly challenging, including extended periods of inactivity and low densities. However, the interspecific variation in snake activity patterns across space and time is critical to understand responses to local environmental gradients. We built species-specific models to understand how spatial and temporal factors affect activity and captures of five species in upland pine forests: Copperhead (Agkistrodon contortrix), Coachwhip (Coluber flagellum), Racer (Coluber constrictor), Western Ratsnake (Patherophis obsoletus), and Western Ribbonsnake (Thamnophis proximus). From mid-May to mid-July across three years (2018, 2019, 2020), we deployed boxtraps in two shortleaf pine forests experiencing different management regimes: 1) South Boggy Slough Conservation Area (subjected to frequent thinning and burning), and 2) Stephen F. Austin Experimental Forest (subjected to infrequent thinning and burning). We observed significantly more A. contortrix and T. proximus captured at the SFAEF compared to SBSCA, whereas we observed the opposite pattern for C. constrictor. As the summer progressed, captures decreased each subsequent month for both C. constrictorand P. obsoletus. Pantherophis obsoletus was the only species to exhibit a response to the weather, where captures decreased with increasing rainfall. None of the spatial, temporal, or abiotic factors were significant predictors of C. flagellum captures. The variation in activity patterns across each forest type may be attributed to microclimate differences as well as the physiological tolerances and habitat preferences of these species. |
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4. 16:00 Do Rates of Evaporative Water Loss Explain the Dramatic Declines of Common Garter Snakes (Thamnophis sirtalis) in Southern California? Sean Farmer*, California State University, Northridge; Robert Espinoza, California State University, Northridge sean.farmer.876@my.csun.edu
Habitat loss and urbanization have dramatically altered Southern California’s remaining natural areas. Specifically, wetlands have been eradicated, necessitating the conservation of wetland-dependent species. Common Garter Snakes (Thamnophis sirtalis) are semiaquatic colubrids that are distributed over most of North America. However, most populations of Southern California T. sirtalis are declining or already extirpated, most presume because of urbanization and climate change. Our goals are to (1) map historic and current T. sirtalis localities and validate presence/absence with field surveys; (2) characterize their historic and current habitats and document changes in microclimates; (3) compare temperature-dependent rates of evaporative water loss (EWL) of T. sirtalis with that of six additional Southern California colubrids; and (4) assess whether changes in climate and microniches have likely interacted with the physiological water requirements of T. sirtalis to reduce regional habitat suitability. We hypothesize that historic habitats will be hotter and drier than those with current T. sirtalis populations, and that the water dependence of T. sirtalis, estimated by EWL, will be higher than those of the other Southern California snakes studied. Our results will help conservation authorities better understand the physiological and habitat needs of T. sirtalis, which will help them manage the few remaining populations in Southern California. Additionally, a deeper understanding of the water requirements of Southern California T. sirtalis could prove invaluable in protecting other wetland-dependent species from environmental stressors related to climate change and urbanization. In such a wetland-depauperate region, these protections are vital to maintaining native biodiversity. |
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5. 16:00 To Warn or to Hide? Eastern Newts (Notophthalmus viridescens) Are Aposematic at Short Range but Camouflaged at Long Range. Eric Guerra-Grenier*, McGill University; James B. Barnett, McMaster University; David M. Green, McGill University eric.guerra-grenier@mail.mcgill.ca
Over the last fifteen years, research on defensive coloration has been going through a paradigm shift. Aposematism and crypsis, long thought to be mutually exclusive antipredator strategies, are now considered as the two extremes of a defensive continuum. Nevertheless, the assumption remains that if an animal is brightly colored and chemically defended, it must be conspicuous to its predators. To put this assumption to the test, we have been studying Eastern newts (Notophthalmus viridescens). These newts, especially during the juvenile stage, possess bright red spots and produce tetrodotoxin skin secretions. They are not only textbook examples of aposematic amphibians, but also of pillars of mimicry rings. Using digital multispectral imaging and visual modelling, we show that the red spots of these newts are in fact only conspicuous to predators when seen from close range and become cryptic with increasing viewing distance. In addition, the shift between conspicuousness and crypsis occurs at different distances depending on the predator: newts become camouflaged under bird vision at around 2 meters and under snake vision at around 8 centimeters. These results remind us of the fact that animals that appear brightly colored to humans under controlled conditions may be well camouflaged to ecologically relevant predators under natural conditions. We argue that research on defensive color patterns should trade the default hypothesis of primary aposematism for one that better reflects the context-dependent nature of most visual signals. |
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6. 16:00 Results from 22 years of Austin Blind Salamander (Eurycea waterlooensis) surveys. Nathan Bendik*, City of Austin Watershed Protection Department; Dee Ann Chamberlain, City of Austin Watershed Protection Department; Sarah Donelson, City of Austin Watershed Protection Department; Matt Westbrook, City of Austin Watershed Protection Department twanto@gmail.com
Since their discovery in 1998, Austin Blind salamanders have remained an enigmatic and infrequently encountered occupant of Barton Springs in Austin, Texas. Although considered to be a subterranean specialist based on cave-associated morphology (reduced eyes and pigment; shovel-shaped snout), Eurycea waterlooensis has only ever been encountered at the surface, where they are likely flushed out from the springs. Population surveys initially targeted their sympatric counterparts, Barton Springs salamanders (Eurycea sosorum), which are observed at a much higher frequency and are a regular occupant of surface habitat near the spring outlets. For the first time, we present survey results of E. waterlooensis spanning a 22-year period. Using data from count and capture-recapture surveys, we examine the frequency of occurrence at the surface of E. waterlooensis in the context of environmental variables and E. sosorum abundance. |
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7. 16:00 Collared Peccary Wallows and Their Effect on an Amphibian Community in a Lowland Tropical Forest in Costa Rica. Alondra Medina*, University of Puerto Rico; Kelsey Reider, James Madison University; T. Mitchell Aide, University of Puerto Rico alondra.medina@upr.edu
Peccaries (Tayassuidae) act as ecosystem engineers for amphibians and reptiles by creating and maintaining aquatic microhabitats called wallows, but further research is needed to fully understand this relationship. In this study, we assessed the herpetological community composition in wallows created by the collared peccary (Pecari tajacu) in a lowland wet forest of northeastern Costa Rica. We compared species richness between peccary wallows and the adjacent leaf litter matrix using multiple detection methods. We complemented standardized visual encounter surveys with passive acoustic monitoring to compare community composition, richness and diversity in wallows and paired control leaf litter plots. Visual and acoustic methods were used to cover the limitations associated with each sampling technique. We found a total of 16 amphibian and 4 reptile species occupying wallows. Our analyses showed that Agalychnis callidryas occupancy was significantly higher in wallows compared to understory habitats. We also found that wallows showed a higher Shannon Diversity Index than leaf litter plots. An analysis of similarities showed that wallow communities of 2012 and 2019 did not differ. Wallow communities may remain constant over time due to the assemblage of semi-aquatic species that use wallows for breeding and foraging. Our study is the first assessment of wallow-breeding amphibians in Central America, and it shows that herpetological communities actively use collared peccary wallows in northeastern Costa Rica. Lastly, it suggests that if peccary populations continue to decline from habitat loss and overhunting, it could negatively impact amphibians and reptiles in lowland tropics. |