Less common than their Eastern Box Turtle relatives, the Ornate Box Turtle is listed as state threatened. Learn more about this “Rare, Remarkable Illinois Reptile.”
Dr. Dreslik and several lab members are presenting posters and talks in Charleston, South Carolina this week for the Turtle Survival Alliance’s 21st Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles
Population structure of the Western Pond Turtle (Actinemys spp.) across twelve military installations in California
Emily Asche, Matthew I. Parry, Thomas S. B. Akre, Robert Lovich, and Michael J. Dreslik
Western Pond Turtle (Actinemys spp.) populations are currently threatened with habitat loss, predation, and shell disease. The synergies among threats have caused severe population declines whereby they are an endangered species in Washington, a sensitive species in Oregon, and a species of special concern in California. It is imperative to investigate their status in California to determine how prevalent threats are and what level of conservation action needs to be taken to avoid declines. We examined the population structure of the Western Pond Turtle populations at twelve military installations across California through sampling in one-week bouts using 50 aquatic traps at one visit per base. We recorded the body size, life stage, and sex of all individuals. Our study is intended to represent a first pass at determining if there are any immediate conservation concerns, such as biases in stage or sex ratios and population size structure.
Detection and occupancy of the Western Pond Turtle (Actinemys spp.)
Matthew I. Parry, Emily Asche, Robert Lovich, Thomas S. B. Akre and Michael J. Dreslik
Low densities, followed by a secretive nature, create challenges for accurately estimating population estimates and site occupancy rates. The Western Pond Turtle (Actinemys spp.) faces range-wide declines and is currently a species of special concern in California. Our project aims to determine their status across 12 military installations using an occupancy/detection framework while attempting to maximize captures during one 50 aquatic trap/four trap night sampling session per installation. Because we sampled areas of known occupancy, we could focus on estimating detection rates. We aim to create an MS Excel tool to determine the detection probabilities while accounting for various environmental and habitat-related covariates.
Survival matters: Comparing the demographic traits of Clemmys and Glyptemys with long-term capture-recapture data
Devin Edmonds, Michael J. Dreslik, Jeffrey E. Lovich, and Carl H. Ernst
Freshwater turtles are one of the most threatened vertebrate groups, with over half of all species at risk of extinction. Overexploitation and habitat loss are the largest threats, with many turtle populations now small, isolated, and needing conservation action to ensure they persist. To enact informed conservation measures and monitor recovery efforts, managers benefit from information about demographic rates like survival and recruitment for highly threatened turtle species. Survival plays a particularly important role in population persistence, considering the life history of most turtle species is characterized by a long lifespan, delayed sexual maturity, and low fecundity. Thus, even small changes in adult annual survival rates can cause otherwise stable populations to decline. We analyzed three historical long-term capture-recapture datasets to estimate annual survival and recruitment for populations of Spotted Turtles (Clemmys guttata), Wood Turtles (Glyptemys insculpta), and Bog Turtles (Glyptemys muhlengerbii) that live in increasingly threatened wetlands and surrounding habitats. All three have ranges characterized by disjunct distributions and often small and isolated populations. Adult sex ratios in turtles can be affected by differences between the sexes in the timing of maturity, rates of mortality, sex-determining mechanism, or differential immigration/emigration. The two Glyptemys species have genetic sex determination while Clemmys has environmental sex determination. This latter distinction could affect each species responses under warming climate scenarios, since Clemmys might be expected to have female-biased populations as global temperatures increase. However, sex-specific differences in survival of Glyptemys species could also occur. Using multi-decadal data, we analyze sex-specific and species-specific survivorship from a site in eastern Pennsylvania where these turtles were sympatric. Our results help inform conservation efforts for three threatened freshwater turtle species and show the strengths of historic long-term data.
Baseline energetic requirements of Ornate Box Turtles (Terrapene ornata)
Andrea L. Colton and Michael J. Dreslik
Increasing ambient temperatures due to climate change may lead to altered behaviors as turtles attempt to regulate internal body temperatures. Increased efforts to maintain temperatures may result in energetic tradeoffs, leading to reduced individual fitness and, thus, population abundance. Estimation of resting metabolic rates for turtles affords calculation of baseline energetic requirements and the potential to predict costs associated with warming landscapes. Using flow-through respirometry, we will determine the resting metabolic rates (RMRs) of adult Ornate Box Turtles (Terrapene ornata) across a temperature gradient to provide information on energetic costs. The baseline estimates will then be used to determine the annual RMR costs on the landscape.
Ranges on the spectrum of recovery: conservation action for the Spotted Turtle and Eastern River Cooter in Illinois
Michael J. Dreslik
Extinction rates in the Anthropocene are significantly higher than background and previous major events. The extinction process can occur when local populations become extirpated, particularly those on the range periphery where habitats are often sub-optimal. Turtles are one of the most critically endangered taxa, with many anthropogenic factors triggering declines. Although jurisdictional boundaries can often complicate conservation, many North American turtles have peripheral populations of conservation concern. Within Illinois, peripheral populations of the Spotted Turtle (Clemmys guttata) and Eastern River Cooter (Pseudemys concinna) are protected as State Endangered; however, their apparent recovery is quite different. I discuss conservation prioritizations, status assessments, and conservation implementation needs for both species in Illinois. Finally, I compare the pathways to recovery for both species.
Conservation Tools and Actions: Oral Thursday PM
Two projects from the INHS PACE Lab were among the 21 projects funded nationally by the 2021 U.S. Fish and Wildlife Service’s Competitive State Wildlife Grant (C-SWG) program.
The first cooperative project is with the Iowa and Illinois Department of Natural Resources, allocated at $499,797 for the joint project titled “Blanding’s Turtle Conservation in Iowa and Illinois, 2022 through 2024”. The project team from the Illinois Natural History Survey (INHS) and National Great Rivers Research and Education Center (NGREEC) comprises Ethan J. Kessler, Michael J. Dreslik, Andrew R. Kuhns, and John A. Crawford. The team was awarded $249,449 for their portion of the project, “Population Assessment and Space Use in a Kankakee Sands Region Blanding’s Turtle Population.” While much work has been done on Blanding’s Turtle populations in the Chicagoland region, this project focuses on lesser-known populations in the Kankakee Sands Conservation Opportunity Area.
The grant will facilitate an intensive capture-mark-recapture study to determine population size and begin to collect demographic data. A subset of turtles will be tracked using radio telemetry and GPS trackers to monitor survival and determine space and habitat use. The data is necessary to determine the amount and extent of suitable habitat available on the landscape and address causes of mortality for this population. The work will build on previous research on Blanding’s Turtles in Illinois and further inform conservation planning.
The second cooperative project is with the Minnesota Department of Natural Resources allocated at $247,892 for the joint project titled, “Regional Assessment of Widespread Mussel Declines: a Multistep Approach to Examine Potential Causes.” The project team from the INHS comprises Sarah A. Douglass and Alison P. Stodola while INHS alum Bernard Sietman will lead Minnesota’s portion. The INHS team was awarded $113,364 for their portion of the project. Freshwater mussels, an ecologically important component of river ecosystems, are experiencing widespread declines. With the award, Douglass and Stodola will investigate potential causes for these declines with the goal of informing conservation guidelines and recovery planning. Additionally, this study is an expansion of a largescale, cooperative project spearheaded by Dr. Wendell Haag, US Forest Service Research Fisheries Biologist, and American Rivers to examine causes of freshwater mussel declines across North America.
Researchers will assess pairs of rivers with similar historic mussel assemblages, comparing a river with relatively intact mussel assemblages and a river with a degraded assemblage. They will develop health metrics and assess habitat characteristics to identify potential causal factors of decline. Juvenile mussels will be propagated and used to assess health in response to potential causes of decline. Another part of the project will use eDNA and targeted sampling to update knowledge of Salamander Mussel populations in Illinois and Minnesota. The research will build on a pilot project previously undertaken by Douglass to use eDNA to detect the critically imperiled species and its host, the Mudpuppy salamander.
In granting these awards, USFWS recognizes the necessity of these two projects to further the goals of the Illinois Wildlife Action Plan to conserve imperiled species and their habitats.
PACE Lab PhD candidate Devin Edmonds participated in the Nachusa Grasslands Science Symposium on April 24th. He presented “An Update on Ornate Box Turtle (Terrapene ornata) Research at Nachusa Grasslands,” work he did for his M.S. studying the state threatened Ornate Box Turtle. Learn more about his research and findings.
Eastern Box Turtle growth is influenced by environmental conditions which in turn can be influenced by vegetative structure. Removal of Autumn Olive and Russian Olive at a site in Illinois occurred during a 16 year mark-recapture study allowing us to analyze impacts of removal on the growth of turtles. The data showed that removing the invasive plants may not negatively impact the growth of the turtles and that growth is variable by individual. This is attributed to reptile growth being influenced by more than just environmental conditions, including genetics.
Read the paper: Edmonds, D., A.R. Kuhns, and M.J. Dreslik. 2020. Eastern Box Turtle (Terrapene carolina carolina) growth and the impacts of invasive vegetation removal. Herpetological Conservation and Biology 15(3):588–596.
PACE Lab herpetologists Andrea Colton and Emily Sunnucks wrote about their experiences continuing our research into the endangered Blanding’s Turtle in northeastern Illinois.
Read about a day in their life in “Behind the Scenes”
Champaign, IL – Protecting and restoring habitats are the most important steps that can be undertaken to protect turtle populations into the future according to a pair of recent papers analyzing 3 decades of data.
The Spotted Turtle, Clemmys guttata, is a small semi-aquatic turtle that inhabits sedge meadow, cattail marsh, wet-mesic prairie, and dolomite prairie in Illinois. It is protected as an endangered species in Illinois, which is at the western edge of its range. The two known populations in Illinois have been the focus of mark-recapture studies since 1988.
Recent analysis found that Spotted Turtle populations are limited by the amount of available habitat, suggesting that management efforts should focus on increasing suitable habitat. Control of cattails (Typha sp.) and restoration of sedges would increase the amount of available habitat.
Adults have a higher survival rate than younger turtles. Predators including raccoons and muskrats can eradicate eggs and juvenile turtles. While caging nests and headstarting juveniles will help the younger turtles, controlling predator populations could benefit all age classes.
Feng, C.Y.; Ross, J.P.; Mauger, D.; Dreslik, M.J. A Long-Term Demographic Analysis of Spotted Turtles (Clemmys guttata) in Illinois Using Matrix Models. Diversity. 2019, 11, 226. doi:10.3390/d11120226
Feng, C.Y.; Mauger, D.; Ross, J.P.; Dreslik, M.J. Size and Structure of Two Populations of Spotted Turtle (Clemmys guttata) at Its Western Range Limit. Herpetological Conservation and Biology 14(3):648–658
PACE Lab head Michael Dreslik and herpetologist Jason Ross presented at the 2019 Spotted, Blanding’s, and Wood turtle conservation symposium held in West Virginia this November.
Population Viability Analysis and the Role of Head-starting for a northern Illinois Blanding’s Turtle Population
Rapid Demographic Assessments for Freshwater Turtles: Filling in Data Deficiencies
Environmental DNA (eDNA) is an emerging tool used to detect rare and difficult to detect species. A recent study by INHS PACE Lab herpetologists used radio telemetry to evaluate and improve the efficiency of this technique.
As part of a species reintroduction program, hatchling Alligator Snapping Turtles reared in captivity were tracked using radio telemetry to assess their survival. This work provided an ideal system for evaluating the efficacy and limitations of using eDNA to detect a bottom dwelling riverine turtle. At each radio location, water samples were collected as well as upstream and downstream of the turtle.
The researchers found that eDNA can be used to detect a benthic turtle species but that detection can be diminished by UV exposure from open canopy. This study shows the importance of continuing to use traditional methods such as radio telemetry to better understand the dynamics of eDNA in the environment.
Read the complete paper in Environmental DNA