This year’s Turtle Survival Alliance conference was held in Tucson Arizona 2024 July 25-28. Several members of the INHS PaCE Lab presented posters and talks, which we’re excited to share with you.
Dr. Dreslik gave a featured presentation during the plenary session,
“Freshwater Turtle and Tortoise Growth: What we know and where to go”
co-authored with Drs Lovich (USGS) and Congdon (Savannah River Ecology Lab).
Growth is a fundamental life history trait expressed as shape, rate, and size at specific times for individuals in a population. Because energy allocated to competing life demands shifts, all expressions have impactful relationships with other life-history traits. In general, the overall growth pattern of turtles is well understood, but representative studies are decidedly lacking for many species and populations. Additionally, we are building a stronger foundation of the drivers and their consequences on growth; few studies have had the luxury of serially examining populations to determine environmental and habitat related effects. Herein, we present the state of knowledge on growth in freshwater turtles, covering aspects such as pattern, seasonality, determinism, dimorphism, extrinsic drivers, maternal effects, and individuality. Finally, we will provide insight into current analytical advances and direction for future work.
PDF of TSA2024 talk
Graduate student Nicholas Dunham presented a poster
“Spatial Ecology of Blanding’s Turtles (Emydoidea blandingii) in an Agricultural Landscape in Northeast Illinois”
co-authored with Ethan Kessler, John Crawford and Michael Dreslik.
Agriculture in Illinois dominates the landscape, leading to widespread alteration of terrestrial and aquatic ecosystems. Much of Illinois’ freshwater wetlands have been heavily channelized and converted into vast networks of ditches in agricultural drainage systems. Thus, these agricultural ditches may represent some of the only available wetland habitats for turtles. A small population of Blanding’s Turtles (Emydoidea blandingii) was discovered living in an agricultural ditch system in Kankakee and Iroquois counties of Northeast Illinois. Blanding’s Turtles use terrestrial and aquatic habitats throughout the season, increasing their mortality risks from farming equipment. To better understand how Blanding’s Turtles utilize an agricultural landscape, we trapped and used VHF radio-telemetry to track 15 individuals (9 females, 6 males) from April to November 2023, totaling 533 locations. Our objectives were to investigate home range sizes, movement rates, and macrohabitat and microhabitat selection by sex and season. The results of our study are preliminary, and data collection will continue from 2024 to 2025. Our results can aid the management of Blanding’s turtles in agricultural-dominated landscapes.Graduate student Emily Asche presented
“Population Structure of the Declining Western Pond Turtle (Actinemys spp.) Across Thirteen Military Installations in California”
co-authored with Matthew Parry, Thomas Akre, Robert Lovich, and Michael Dreslik.
The Western Pond Turtle (Actinemys spp.) is currently undergoing assessment to be listed as a Threatened species under the Endangered Species Act. It is designated as a species of special concern in California, sensitive/critical in Oregon, and endangered in Washington, indicating an imminent likelihood of listing. Habitat loss, predation, and shell disease have caused significant population declines, yet there remains a scarcity of data necessary for informed management decisions. Understanding the existing population structure of remaining populations is pivotal for initiating effective conservation strategies. We are gathering demographic data from thirteen military installations across their California range to assess the level of concern and identify key management priorities. Data collection spans two seasons, with sampling conducted in week- long intervals using 50 aquatic traps per base, supplemented by relevant data from prior or concurrent studies at each installation. Recorded parameters include body size, life stage, and sex of all individuals to characterize the population structure. Additionally, growth rate and recruitment will be derived from the final dataset. Our study’s objective is to delineate targeted conservation efforts for species recovery.Rose Arnold presented
“Development of a Detection Model of the Blanding’s Turtle (Emydoidea blandingii) to Guide Conservation Prioritization in Illinois”
co-authored with Michael Dreslik
Like many turtle species, Blanding’s Turtle (Emydoidea blandingii) populations are declining range-wide due to the synergistic effects of habitat fragmentation, loss, and degradation. In Illinois, Blanding’s Turtle populations are isolated within urbanized or agricultural landscapes, thus hindering migration. Additionally, the status of the species at many historical locations remains unknown, whereby many populations may already be functionally extirpated. Thus, determining the status of populations in Illinois is the paramount conservation priority. Surveys for Blanding’s Turtles require a substantial investment of resources (time, funds, and effort) through trapping and visual searches. Currently, there are few tools for quantitatively determining the effort needed to confirm site occupancy. Here, we construct a detection probability model considering temporal, effort, habitat, weather, and environmental variables. The model will allow surveyors to calculate how much effort is necessary to determine occupancy status for a given site under a given set of conditions. The findings from the initial model sets suggest temporal factors exert the most influence on detection, particularly when compared to weather. However, even in strong-performing models, predicted detection rates remained low.Chitra Rehka Basyal presented a poster
“Structure and Health of a Freshwater Turtle Assemblage in a Highly Developed Ecosystem”
co-authored with Michael Dreslik, Ny Aina Tiana Rakotoarisoa, Laura Adamovicz, and Matthew Allender
Turtles have important ecological roles in wetlands as omnivores, scavengers, food sources, and nutrient recyclers. Despite such importance globally, their populations are declining, with the proliferation of infectious diseases emerging as a major threat. Our study aims to assess turtle’s community structure and evaluate the physical health of those turtle individuals. We began a turtle capture-mark-recapture survey at a university wetland to study assemblage, composition and individual health. In our first year (2023), we captured 39 turtles of 6 species. Based on the species composition, our study suggests the site may be used for illegal pet releases. We screened 37 individuals for adenovirus, herpesvirus, ranavirus, and mycoplasma using conventional and quantitative PCR. Two species (Painted Turtle [Chrysemys picta] and Red-eared Slider [Trachemys scripta elegans]) were adenovirus-positive, with the virus strain being 99% similar to Sulawesi Tortoise adenovirus. No mycoplasma, Ranavirus, or herpesvirus was detected. Moreover, the Red-eared Slider is likely a natural host of Sulawesi Tortoise adenovirus (STAdV-1). The study forms a baseline for long-term demographic monitoring and health assessments of the turtle assemblage.
