New paper on Alligator Snapping Turtle movement by ARC program leader Ethan Kessler

Translocated Alligator Snapping Turtle with radio transmitter attached

A paper just out this week in the Journal of Wildlife Management, “Movement behavior and passive dispersal of a reintroduced population of alligator snapping turtles” found that translocated AST behaved similarly to wild populations, and is largely passive. This can have conservation implications as reintroduced animals may be transported downstream by high flows.

Abstract

Maladaptive movement behavior is a leading cause of failure for reptile reintroductions, thus characterizing movement for translocated populations is important to project success. From 2014–2016 we radio-tracked 183 immature reintroduced alligator snapping turtles (Macrochelys temminckii) using very high frequency telemetry in a stream in southern Illinois, USA. We assessed environmental, temporal, morphometric, and microhabitat factors influencing movement, including post-release dispersal from reintroduction sites, movement probability, and step length. We used directional statistics to investigate the effects of precipitation and age on directional movement in the stream. Numerous factors influenced active movement, including ambient temperatures, time since release, use of log jams, turtle size, and age. Precipitation had an age-biased effect on movement. Directional analyses suggested that movement was largely passive as turtles were swept downstream with increased discharge. Overall, the behavior of reintroduced alligator snapping turtles was similar to that reported in wild populations. Passive downstream transport has implications for reintroduced and natural populations as a force for unintentional emigration in channelized streams under current conditions and future high flow regimes.

Read the full paper here.

Kessler, Ethan J. and Michael J. Dreslik. 2023. Movement behavior and passive dispersal of a reintroduced population of alligator snapping turtles. Journal of Wildlife Management. https://doi.org/10.1002/jwmg.22511

September 26, 2023September 26, 2023

New Timber Rattlesnake publication by PhD candidate Andrew Jesper

Trailcam image of Timber Rattlesnake at den opening

Abstract: Many temperate reptiles survive winter by using subterranean refugia until external conditions become suitable for activity. Determining when to emerge from refugia relies on the ability to interpret when above-ground environmental conditions are survivable. If temperate reptiles rely on specific environmental cues such as temperature to initiate emergence, we should expect emergence phenologies to be predictable using local climatic data. However, specific predictors of emergence for many temperate reptiles, including the Timber Rattlesnake (Crotalus horridus), remain unclear, limiting our understanding of their overwintering phenology and restricting effective conservation and management. Our objectives were to identify environmental cues of spring emergence for C. horridus in Illinois to determine the species’ emergence phenology, and to examine the applicability of identified cues in predicting emergence phenology across the species’ range. We used wildlife cameras and weather station-derived environmental data to observe and predict the daily surface presence of C. horridus throughout the late winter and early spring at communal refugia in west-central and northern Illinois. The most parsimonious model for predicting surface presence included the additive effects of maximum daily temperature, accumulated degree days, and latitude. With a notable exception in the southeastern U.S., the model accurately predicted the average emergence day for eight other populations range wide, emphasizing the importance of temperature in influencing the phenological plasticity observed across the species’ range. The apparent broad applicability of the model to other populations suggests it can be a valuable tool in predicting spring emergence phenology. Our results provide a foundation for further ecological enquiries and improved management and conservation strategies.

Read the paper at:

Jesper AC, Eckert SA, Bielema BJ, Ballard SR, Dreslik MJ. 2023. Phenology and predictors of spring emergence for the Timber Rattlesnake (Crotalus horridus) PeerJ 11:e16044 https://doi.org/10.7717/peerj.16044

September 6, 2023September 6, 2023

New publication from aquatic ecologist Hugo Ruellen

INHS PaCE Lab’s aquatic ecologist, Hugo Ruellen is lead author on a recent publication stemming from his M.Sc. research on freshwater mussels: “Predicting suitable habitat for surrogate species of critically imperiled freshwater mussels to aid in translocations.”

Mussel translocations have been used to mitigate the impacts of in-stream construction projects, including bridge replacements. This work developed a model to predict suitable habitat for mussels. “Knowing where and how much suitable habitat is present in rivers is essential to the conservation and long-term persistence of endangered freshwater mussel species, and habitat suitability models such as these are important tools for achieving these goals.”

Ruellan, Hugo Y., Kirk W. Stodola, Alison P. Stodola, and Jeremy S. Tiemann. 2023. Predicting suitable habitat for surrogate species of critically imperiled freshwater mussels to aid in translocations. Freshwater Science 42(3): 296-314. https://doi.org/10.1086/726740

August 5, 2023August 3, 2023

INHS PaCE Lab at Turtle Survival Alliance Symposium

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

July 15, 2023July 18, 2023

INHS PaCE Lab at the Joint Meeting of the Ichthyologists and Herpetologists

Dr. Dreslik and graduate students Blaine Hiner and Zander Perelman attended and presented at the 2023 Joint Meeting of Ichthyologists and Herpetologists in Norfolk VA, July 12-16.

The Continued Decline of the Eastern Massasauga in Illinois, from Distribution to Population Scales
Michael Dreslik, Tyler Stewart, Tom Beauvais, John Crawford

Marked changes have occurred to the earth’s biomes through the
Anthropocene due to human activity altering landscape-level processes. Many species reliant on ecosystems that have been heavily impacted have suffered massive range contractions and population declines. Given most prairies have been converted for agricultural purposes, species occupying those systems have exhibited precipitous declines. Here we examined the decline of Eastern Massasauga in Illinois using approaches at different scales, including g historical and contemporary distributions using Species Distribution Models and element-of-occurrence records to specific population trends using demographic monitoring. Unfortunately, the prognosis for the continued presence of the species on Illinois’ landscape is not promising.

Relating Habitat Parameters to Population Abundances in the Eastern Massasauga
Michael Dreslik, Sarah Baker, John Crawford, Andrew Stites, Ethan Kessler

Before conservation measures can be taken, three questions about a species must be addressed: 1) where are they distributed; 2) what habitats do they use; and 3) how many do we have on the landscape? Habitat suitability index
(HSI) models are primarily used to predict habitat quality on the landscape for a given species, but they also provide a method to answer the second question with the supposition that the higher the suitability, the greater the abundance. The link between suitability and abundance estimations is often not made, even though both are critical for measuring conservation success. Here we examined several habitat parameters to determine their efficacy at predicting population abundances of the Eastern Massasauga at their southern range limit in Illinois. Specifically, we tested whether parameters in an existing HSI model provided range-wide applicability or if proximate point- based or remote-sensed lidar-based measures of vegetation cover were better predictors.

Extrinsic Factors Influencing Hibernacula Occupancy of the Eastern Massasauga
Blaine Hiner, Michael Dreslik

Determining a species’ habitat use and distribution across a landscape
is essential for understanding the prevalence of declines due to larger-scale threats. At the landscape level, anthropogenic threats such as climate change and habitat destruction have triggered global population declines; thus, specific data crucial to combat declines must assess their impacts.
Collecting landscape-level data has been improved by the advent of occupancy modeling, which can elucidate the impacts anthropogenic factors have on population presence. The Eastern Massasauga is particularly vulnerable to extreme natural events from climate change and habitat loss in the western third of its range, particularly due to its reliance on specific overwintering habitats, which have been largely converted to agriculture. Extrinsic factors affecting overwintering habitat occupancy could include the burning regime, flooding events, aberrant seasonal climate, patch size, and juxtaposition of patches across the landscape. Using a long-term capture-mark-recapture dataset (1999 – present), we determined if extrinsic management and climate factors affected hibernacula occupancy rates. Our results would afford prioritization of site-specific habitat management actions to mitigate factors negatively impacting site occupancy.

Male-male Combat in Free-ranging Sistrurus Rattlesnakes
Zander Perelman, Terence Farrell

Although male-male combat is documented in numerous snake species, reports of combat behaviors are seldom more detailed than simple descriptions. Combat between snakes in the genus Sistrurus is rarely observed and only one previous account, focused on captive specimens, offered behavioral descriptions and analyses. Here, we discuss combat events between free-ranging Eastern Massasaugas (S. catenatus) in Pennsylvania, and free-ranging Pygmy Rattlesnakes (S. miliarius) in Florida. We used video recordings to describe and quantify observed combat behaviors. Additional behavioral contexts, specifically observed copulation (S. catenatus) and active defeat (S. miliarius), allowed for quantified behaviors to be analyzed and compared with knowledge of the winning male in both combat events. Quantifying and analyzing these two events has provided insight into important behavioral determinants of combat success in Sistrurus rattlesnakes. Observation of snake combat is opportunistic, and consequently, detailed behavioral descriptions and analyses as performed here are rare in natural settings. Such social behaviors have clear implications for reproductive success and fitness, and comprehensive analyses of combat behavior, as accomplished here, may prove useful in understanding the evolution of these reproductive behaviors.

July 11, 2023July 11, 2023

INHS PaCE Lab at Emydine Conservation Symposium

Dr. Dreslik, Rose Arnold, Emily Asche, Andrea Colton, and Izabelle Jaquet presented at the Emydine Conservation Symposium at Juniata College in Huntingdon, Pennsylvania July 10th-12th, 2023.

Conservation Guidance, Status, Prioritization, and Implementation for the Recovery of the Spotted Turtle, Clemmys gutatta, in Illinois

Michael J. Dreslik*,

The Spotted Turtle (Clemmys gutatta) has always been a rare species in Illinois and was once thought extirpated. Its historical distribution likely encompassed the former interdunal wetlands along Lake Michigan, now occupied by the greater Chicago metropolitan region. Few populations remained on the landscape post- settlement, and only two remain extant, with one exhibiting severe decline. As such, the Spotted Turtle is protected as an endangered species. The Illinois Department of Natural Resources has instituted a new framework for species conservation consisting of three primary works, a Species Guidance Document, Status Assessment, and Conservation Implementation Plan. In addition to this effort, an Amphibian and Reptile Conservation Strategy was developed using expert solicitation to prioritize conservation actions and delineate threats. Using the information available, I will briefly cover where we are with the recovery of the Spotted Turtle in Illinois.

Population Structure of Three Isolated Northern Illinois Blanding’s Turtle (Emydoidea blandingii) Populations

Rose A. Arnold*, Emily A. Asche, Michael J. Dreslik,

The Blanding’s Turtle (Emydoidea blandingii) is declining range-wide due to synergistic threats associated with habitat fragmentation, loss, and degradation. In Northern Illinois, Blanding’s Turtle populations are often isolated in an urbanized landscape with little chance for interpopulation migration. Thus, it is imperative to monitor populations inhabiting isolated patches because of risks from demographic and environmental stochasticity due to small population dynamics. By collecting data on sex, stage, and morphometrics on all captured individuals, our study will determine if concerning patterns or biases in the size, sex, or stage structure exist in three northeastern Illinois populations. For example, biased sex ratios toward adult males could indicate decreased adult female abundance and impact population growth through depressed recruitment rates. Additionally, a skewed stage structure toward juveniles could indicate decreased adult abundance from unusually low adult survivorship. Our results could aid regional wildlife managers by signaling potential threats to the demography of small, isolated populations.

Reducing the Risk of Prescribed Burns on Ornate Box Turtles (Terrapene Ornata) in Illinois

Izabelle S. Jaquet*, Devin A. Edmonds, Andrea L. Colton, Ethan J. Kessler, Michael J. Dreslik

Native prairie ecosystems and associated herpetofauna have significantly declined throughout the 21st century. Once common throughout Midwest prairies and grasslands, the Ornate Box Turtle (Terrapene ornata) is of conservation concern in multiple states, including Illinois. Notable threats to population persistence include road mortality, illegal harvesting, and increased predation from mesopredators. Unfortunately, prescribed burns present an additional threat. While necessary, there is an increased risk of harming Ornate Box Turtles if burns are conducted between spring emergence and the beginning of winter dormancy. The loss of even a few individuals can drastically reduce population viability. To better understand the timing of dormancy, we used radiotelemetry to monitor 26 Ornate Box Turtles across three Illinois sites. We also collected shell and soil temperatures with data loggers to determine when and under what conditions turtles are at risk from burns. By combining radiotelemetry observations with shell temperature data, we determined when turtles were above ground. We then created a model predicting emergence based on environmental variables, such as air temperature, precipitation, and time of year. The best model to predict above ground activity considered the interaction of day of year and current air temperature. Our results can aid land managers and ecologists in determining the best time to conduct prescribed burns in Ornate Box Turtle habitat.

Baseline Energetic Requirements of Ornate Box Turtles (Terrapene ornata)

Andrea L. Colton*, Michael J. Dreslik,

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, 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.

February 16, 2023

The Illinois Natural History Survey Population and Community Ecology Lab is seeking a Terrestrial Ecologist to conduct basic and applied research assisting with ongoing surveys for bats. This position will assist with surveys of other taxa as time allows. This position will be based in Champaign, Illinois. See more or apply

November 18, 2022

We’re Hiring an Aquatic Ecologist

The Illinois Natural History Survey Population and Community Ecology Lab is seeking an Aquatic Ecologist to conduct basic and applied research assisting with ongoing surveys for aquatic amphibians and reptiles, freshwater mollusks, and fishes. This position will be based in Champaign, Illinois. See more or apply

November 10, 2022November 11, 2022

We’re Hiring!

The Illinois Natural History Survey Population and Community Ecology Lab is seeking a Terrestrial Ecologist to conduct basic and applied research assisting with ongoing surveys for terrestrial reptiles, bats, and noctuid moths. This position will be based in Champaign, Illinois. See more or apply

PACE Lab News