Half of the INHS PaCE Lab presentations at this year’s Midwest Fish and Wildlife Conference were about turtles, with 5 oral presentations and 1 poster presentation.
Devin Edmonds presented “Ditch Turtles: Movement and Habitat Selection of Blanding’s Turtles (Emydoidea blandingii) at the Southern Edge of their Distribution” co-authored with Ethan Kessler and Michael Dreslik.
Habitat use is an important aspect of a species’ ecology, especially for range-limited species or populations impacted by land use change. However, habitat use can exhibit range-wide geographic variation due to numerous factors, such as clinal variation in environmental conditions. Additionally, habitat availability may be constrained in anthropogenically modified landscapes by barriers or expanses of unsuitable habitat. We studied the spatial ecology of a Blanding’s Turtle (Emydoidea blandingii) population in central Illinois to learn about the species’ habitat preferences and movement in a wetland complex insularized by agricultural land use. A combination of radiotelemetry and GPS loggers allowed us to record 2,105 locations collected from 18 individuals from 2022–2024. Turtles frequently used agricultural ditches and channelized streams for movement, suggesting such overlooked habitat features can be important corridors. Using step selection functions to assess habitat selection, we identified vital habitat features. Our results show the importance of agricultural drainages in facilitating movement in heavily fragmented landscapes and are indicative of the habitat selection of species occupying suboptimal habitat. While our study illustrates potential adaptability to agricultural landscapes, further work is required to determine the viability of such populations in the face of a potentially hostile agricultural context.
Michael Dreslik presented “Transient Demographic Analysis for Conserving a Critically Imperiled Turtle” co-authored with Ethan Kessler, Rose Arnold, and Devin Edmonds.
Traditional population models often focus on long-term growth, obscuring critical short-term vulnerabilities. Such oversight can lead to ineffective or even detrimental conservation strategies when considering immediate environmental stochasticity and disturbances. Our study analyzes short-term, transient dynamics for two imperiled Spotted Turtle (Clemmys guttata) populations in Illinois using an Integral Projection Model foundation. We then apply a modern analytical framework to quantify inherent population volatility using scale-invariant metrics, followed by a transient stochastic population viability analysis. Our analyses identified specific vital rates driving short-term stability, which may differ from rates influencing long-term growth. Additionally, we quantified potential trade-offs between management actions promoting rapid recovery versus actions ensuring resilience. Ultimately, our work will provide managers with a robust and nuanced understanding of population stability and, hence, more effective conservation decisions.
Becky Blankenship presented “Ornate Box Turtle Response to Habitat Re-creation” co-authored with Michael Dreslik and Joseph Milanovich.
Agriculturally driven habitat loss is one of the greatest causes of biodiversity loss globally, with reptiles being particularly vulnerable to such losses. Due mostly to land conversion to agriculture, Illinois has lost over 99% of its historical prairies, with only 955 ha of remnant sand prairies remaining. The Ornate Box Turtle (Terrapene ornata) is considered “Vulnerable” to “Critically Imperiled” throughout most of its range and is listed as state-threatened in Illinois. Understanding the spatial ecology of Ornate Box Turtles is an important aspect of this species’ conservation because it is highly philopatric, returning to the same locations for nesting and overwintering, and having high levels of home range overlap between years. Although numerous factors influence Ornate Box Turtles’ spatial ecology, there is a lack of longitudinal research on spatial response to large-scale re-creation of habitat. Using location data collected for 11 turtles between 2014-2015, and 13 turtles between 2021-2024, I tested whether the conversion of agricultural lands back to sand prairie influenced home range size. I also examined habitat selection between the early and late restoration periods. The restoration period, number of location points, duration tracked, and sex did not significantly influence home range size. Overall, home ranges decreased by 68% after restoration; however, this was a result of individual variation rather than a response to restoration. The conservation of Ornate Box Turtles in Illinois is dependent upon the persistence and restoration of sand prairies, and land managers need to target restoration efforts to areas that are occupied and readily available to individuals.
Claire Dietrich presented “Initial Survey of Freshwater Turtle Assemblages at Public Nature Preserves in Northeastern Illinois” co-authored with M.J. Dreslik.
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 18 publicly owned forest preserves, conservation areas, and mitigation sites for aquatic turtles to determine species richness, diversity, and evenness of the present 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 ranged from 0 to 1.31, while evenness indices varied from 0.38 to 1. We intend to continually reassess turtle assemblages at all sites on a five-year rotation to gain a long-term temporal understanding of demographic trends.
Rose Arnold presented “Identifying Predictors of Detection and Estimating Detection Probabilities of Illinois Blanding’s Turtles” co-authored with M.J. Dreslik.
Low detectability of cryptic and endangered species makes population monitoring challenging, requiring substantial time and resources, particularly for freshwater turtles. Robust monitoring and detection of populations provides managers with reliable demographic data for targeted conservation. A lack of demographic data hinders regional conservation goals, as is the case with the Blanding’s Turtle (Emydoidea blandingii) in Illinois. The demographic data needs are compounded by the species’ cryptic nature and rarity. Thus, timing monitoring periods when Blanding’s Turtle detection is maximized could guide and improve conservation efforts. To identify optimal periods, we constructed detection probability models using historic and current capture data from five occupied sites in Illinois. The models test detection hypotheses using temporal, effort, and weather covariates. Our findings will reveal when detection rates are maximized, therefore enabling more strategic and cost-effective efforts.
Chitra Basyal presented a poster on “Effects of Microplastic Pollution on Hematological Parameters of Spotted Turtles (Clemmys guttata)” co-authored with Laura Adamovicz, John Scott, Lee Green, and M.J. Dreslik.
Plastic consumption by animals is a major global concern, as ingestion and entanglement negatively affect physiology, survival, and reproduction across numerous species. Turtles are no exception, as their widespread presence in freshwater ecosystems makes them particularly vulnerable to microplastic bioaccumulation. As integral components of aquatic food webs, turtles can also transfer pollutants across trophic levels, underscoring broader ecological risks. Although the effects of microplastics on marine turtles have received increasing attention, the impacts on freshwater turtles remain poorly understood. This knowledge gap highlights the urgent need to investigate the effects of plastic pollution on freshwater turtles, particularly for endangered species. Our study represents a pioneering effort to address this gap by examining plastic ingestion in adult female Spotted Turtles through fecal analysis, while simultaneously assessing hematology. Results revealed a high prevalence of microplastic pollution even within protected habitats. Understanding these impacts is essential for developing effective conservation strategies and mitigating the broader ecological consequences of plastic pollution.
