Session 20: Herpetology Ecology IIRoom: Ballroom 111B2022-07-29 10:30 - 11:15 |
| Moderator: Chris Feldman |
|
1. 10:30 Testing Assumptions of Historical Occurrence Use in Species Distribution Models Using Flatwoods Salamander Data. Jason Bracken*, Miami University; Amelie Davis, Miami University; Katherine O'Donnell, USGS; William Barichivich, USGS; Susan Walls, USGS; Tereza Jezkova, Miami University brackejt@miamioh.edu
Occurrence data used to build species distribution models may include historical records from locations in which the species may no longer exist. When these records are paired with contemporary environmental values that no longer represent the conditions the species experienced, models may create false associations that can hurt predictive performance. The extent of mismatching increases with the number of historical occurrences and with inclusion of environmental variables that are prone to change over time. But species of concern are often lacking in sufficient occurrences records to properly inform models without inclusion of historical occurrences, creating a potential dilemma for modelers. We tested model performance across use of historical occurrences and environmental variable sets of varying persistency using data sets from federally protected Flatwoods Salamanders. Results suggest that inclusion of historical occurrences may be generally beneficial, even in some counter intuitive scenarios, such as using impersistent variables while prioritizing specificity. |
|
2. 10:45 Temporal Variation in Occupancy Dynamics of Ringed (Ambystoma annulatum) and Marbled (A. opacum) Salamanders in Missouri. Tom Anderson*, Southern Illinois University Edwardsville; Jon Davenport, Appalachian State University; Bill Peterman, Ohio State University; Jacob Burkhart, Appalachian State University; Freya Rowland, University of Missouri thander@siue.edu
Documenting species occurrences in different habitat patches across spatiotemporal gradients is critical for understanding demographic trends. Species occurrence information also can help inform management actions by determining consistently occupied areas versus infrequently used areas. Identification of the drivers of consistently occupied patches is then critical, as they may indicate high quality habitats. We monitored the occurrence of ringed (Ambystoma annulatum), a Species of Conservation Concern, and marbled (A. opacum) salamanders from 2012-2022 at Fort Leonard Wood, Missouri. We repeated surveyed between 50-166 wetlands for the presence of each species during the larval period using a combination of minnow traps and dipnets. We analyzed whether occupancy was predicted by either habitat variables (e.g., canopy cover or hydroperiod) or climatic variables (e.g., drought or winter severity). We found that ringed salamanders showed a significant positive trend in occupancy through time, while marbled salamanders showed a significant decline in occupancy. Annual detection probabilities for both species always exceeded 75%. In both species, winter minimum temperatures were positively related to occupancy probabilities. Additionally, fall drought indices were positively related to larval occupancy in ringed salamanders. This indicates warmer winters and less severe droughts in the fall increased the likelihood of larval occurrence. Habitat features had limited effect on ringed salamander occupancy, while marbled salamanders had moderate increases in occupancy in response to shorter hydroperiods and reduced amount of forest surrounding wetlands. Overall, our results show that species co-occurring within the same landscape can have contrast trends in occupancy, and are impacted by climatic variation. |
|
3. 11:00 Population and Assemblage Structure of Aquatic Turtles in Two Neighboring Freshwater Springs: A Baseline for Future Studies and Management Decisions. Wayne Osborn, Pine Ridge High School; Eric Munscher, SWCA Environmental Consultants; J. Daren Riedle, Kansas Department of Wildlife, Parks, and Tourism; Andrew D. Walde, Walde Research and Environmental Consulting; Tabitha Hootman, Turtle Survival Alliance; Madeleine Morrison, University of Florida; Michael Skibsted*, Santa Margarita Catholic High School; Andrew S. Weber, National Park Service; Brian Bower, Turtle Survival Alliance; Brian P. Butterfield, Freed-Hardeman University; J. Brian Hauge, Peninsula College skibstedm@gmail.com
As anthropogenic influences increasingly alter the environment there is an increasing need for baseline data to better inform ecosystem management decisions. Specifically, long term data on populations of species within spatially confined areas can have significant, positive, impacts on understanding ecosystem functionality on both a short and long temporal scale. Due to their high density and diversity within the waterways of Florida, freshwater turtles have a large impact on the ecosystem. Investigating turtle assemblage structure and population dynamics is therefore valuable in better understanding entire ecosystems and can provide data on which to base conservation actions and guide further questions investigating ecosystem processes. Here we provide baseline data on the assemblage structure and population demographics of turtles at two neighboring spring systems in Florida based on twelve years of mark-recapture data. Estimates of apparent annual survival (?), recapture probability (p), and total population size are calculated for the four most commonly encountered species at the two springs. Demographic analyses demonstrate differences in age class of turtles at both springs. Biomass estimates are generated to analyze the prevalence of each species within both systems. By establishing a baseline, future assemblage analyses will have data to compare to, allowing for more insight into potential baseline shifts, and associated ecological change. |