Three members of the INHS PaCE Lab, Dr. Michael Dreslik, Emily Asche, and Claire Dietrich, attended the 23rd Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles, held in Chattanooga, TN July 20-25, 2025.
Emily Asche presented a paper “Assessing Population Structure and Conservation Priorities for the Western Pond Turtle (Actinemys spp.) on California Military Installations.” The paper was co-authored with Matthew Parry, Michael Dreslik, Robert Lovich, and Thomas Akre.
Abstract: The Western Pond Turtle (Actinemys spp.) is currently under review for listing as a Threatened species under the Endangered Species Act. Widespread population declines driven by habitat loss, predation, and shell disease have led to its designation as a Species of Special Concern in California, sensitive/critical in Oregon, and endangered in Washington. Despite regional protection, federal listing remains uncertain, emphasizing the urgent need for data to guide conservation. To address critical knowledge gaps, we conducted a two-year demographic study across 13 military installations spanning the species’ California range. Standardized week-long trapping sessions yielding data on body size, life stage, and sex. The metrics were used to estimate local abundance to establish a baseline to inform population health and trajectory. Our analysis revealed variations in demographic composition, site-specific abundance, and growth dynamics across installations, identifying high-risk populations and areas with potential recovery. Our findings are essential for prioritizing conservation actions, informing management of military lands, and contributing to range-wide assessments necessary for the species’ recovery planning.
Claire Dietrich presented a poster “Initial Survey of Freshwater Turtle Assemblages at Thirteen Nature Preserves in Northeastern Illinois.” The poster was co-authored with Michael Dreslik.
Abstract: Urbanization of the Chicago metropolitan area has drastically altered the landscape of northeastern Illinois over the past two centuries. Once dominated by forest and marshy wetlands, the region is now characterized by dense urban centers highly fragmented by several major roadways. The resulting loss of natural habitat has impacted regional abundances of some turtle species, such as the state-endangered Blanding’s Turtle (Emydoidea blandingii). Despite modern environmental protections, fragmentation and degradation of the remaining habitat provide little opportunity for populations to expand or recolonize their former range naturally. We sampled thirteen publicly owned forest preserves, conservation areas, and mitigation sites for aquatic turtles with baited hoop traps to determine species richness, diversity, and evenness of the turtle assemblages. Species richness ranged from 1 to 5, with most assemblages comprising common species considered resilient to anthropogenic disturbance such as the Painted Turtle (Chrysemys picta) and Common Snapping Turtle (Chelydra serpentina). Diversity indices were low overall, ranging from 0 to 1.19, but evenness indices varied from 0.38 to 1. We intend to continually reassess turtle assemblages at the sites on a five-year rotation to gain a long-term temporal understanding of demographic trends.
Dr. Dreslik presented a paper “Population Ecology of Spotted Turtles (Clemmys guttata) in Two Isolated Illinois Wetlands,” co-authored with Devin Edmonds, Rose Arnold, and Ethan Kessler.
Abstract: Over sixty percent of evaluated freshwater turtle species are assessed as at risk of extinction by the IUCN Red List. Overexploitation is the greatest threat, with habitat degradation, urbanization, pollution, and the ongoing effects of climate change also having large impacts. Consequently, many freshwater turtle populations are small, isolated, and declining, as is the case for the Spotted turtle (Clemmys guttata). The species has declined across its range in the eastern U.S., with only two populations remaining in Illinois at the western edge of its distribution. We conducted long-term capture-mark-recapture surveys and leveraged data collected over three decades to create demographic models of growth, survival, and reproductive output formulated into an integral projection model framework. The framework evaluates the probability of population persistence and how changes in vital rates affect population growth. Our results show the benefits of integrating size-based data sources for population assessments and the value of long-term monitoring, with implications for improving conservation efforts for Spotted Turtles in Illinois and throughout their range.
