Herpetological Field Assistant Taylor West came across a Western Hognose Snake last week while surveying sand prairies. Given the hot temperatures, she and fellow field assistant Tristan Schramer offered the snake some water. Video of the encounter has been shared over 10,000 times!
Historically the Ornate Box Turtle was known from 45 counties in Illinois. Today you can count the number of counties with confirmed populations on two hands. This decline landed the species on the List of Endangered and Threatened Species of Illinois in 2009, with habitat loss and road mortality being the greatest threats to its continued survival.
We had the opportunity to survey two of the largest known Ornate Box Turtle sites this past week, with the goal of finding, measuring, and marking as many turtles as possible. With enough recaptures, we can calculate how likely it is for an individual to survive from one year to the next and determine population size. This helps us answer questions including: has population size changed over time? Is the population stable, increasing, or decreasing? Is the population at risk of extinction?
Searching for reptiles and amphibians is often quite tedious. You have to carefully scan ahead of each step for movement before a snake gets away, or spend hours flipping over logs to find the particular salamander you are looking for.
Fortunately, we were assisted on our survey by John Rucker and his Boykin Spaniels, who are not pets but rather working dogs. Years ago one dog proudly brought John Rucker a box turtle it turned up in the woods of Tennessee. He praised the dog and soon it brought back another one in its mouth. Eventually he turned his group of turtle finding dogs into a profession, helping biologists find these once common but increasingly rare chelonians for study.
With John’s dogs, our work was made easy. They carried on ahead of us, their noses to the ground, brown bodies nearly concealed by knee-high grass. When a turtle was found, a dog picked it up in its mouth and carried the reptile like a precious toy, walking to John with pride and eyeing anyone else who offered to take the turtle from it with suspicion. John praised the dog and then gave the turtle to one of us to to be worked up.
To keep track of individual turtles we are catching and whether they survive from one year to the next we mark each turtle with a code. The process is called shell notching, and involves cutting little pieces out of the marginal scutes (the sections of shell that border the outer edge) to assign a unique identification code to each individual turtle. The scutes are numbered from one to twelve on left and right sides, and by notching different combinations of scutes on each side more than 30,000 individuals can be individually identified. For example, by cutting a little section of shell on the first scute on the left side and the third scute on the right, you have just identified an individual as 01L-03R. When done properly, the shell notches stay with the turtle for the rest of its life.
Mortality events due to disease outbreaks have been documented in the closely related Eastern Box Turtle, and there is concern that the Ornate Box Turtle is also at risk. While we were marking and measuring turtles, Dr. Matt Allender and members of the Wildlife Epidemiology Lab were giving each turtle a physical exam, drawing blood, and swabbing their mouth and cloaca to screen for diseases and monitor health. Their work is providing a baseline for future studies on the health of box turtle populations.
With the help of the turtle dogs, we found more than one hundred turtles at the first site and nearly seventy at the second. The data is now awaiting entry and analysis, but several turtles we found were originally marked by the Illinois Department of Natural Resources in 1988. At more than 30 years of age, these individuals are approaching the maximum known lifespan for the species.
Together with the population health assessment, we expect our ongoing project will guide conservation efforts for the Ornate Box Turtle in Illinois and help ensure its continued survival.
PACE Lab leader Mike Dreslik was interviewed by the News Gazette to answer a reader’s question: “After reading the article about Snake Road in southern Illinois, I started wondering what species of snakes are found here in central Illinois? Have any new species been found over the last few years, with the milder winters?”
In addition to listing off species found in the area, Dreslik said, “Although it seems the winters are getting warmer, especially as spring approaches, we have not seen any new species of snakes moving into Illinois, we just see snakes emerging from their winter slumber sooner.”
Rising temperatures could benefit the Common Snapping Turtle.
CHAMPAIGN, ILL. — A recently published study of snapping turtle nests at Gimlet Lake in Garden County Nebraska from 1990 – 2015 found that warmer fall temperatures positively correlate to larger eggs and larger numbers of eggs, while warmer spring temperatures are negatively correlated with egg size and number.
Nesting females were observed and after depositing eggs, captured, measured, marked, and released. The nests were excavated and eggs were counted and measured before being reburied.
Maximum egg size is limited in many turtle species by the size of the female, specifically the pelvic aperture, thus surplus resources are used to develop a greater number of eggs rather than larger eggs. Although this limitation is present in many species of turtles, it was clear a different pattern existed within Snapping Turtles (Chelydra serpentina). Large adult snapping turtles are not restricted in the size egg they can produce and in warmer years, produced larger eggs but the same number. Small adult snapping turtles, on the other hand, did not increase the size of their eggs, but produced larger clutches in warmer years.
Most temperate zone turtles begin developing their embryos in the fall, suspend development over the winter, and complete development in the spring. Snapping turtles complete the majority of their development in the fall, which may reduce the impact of winter and spring climate conditions.
Forming the eggs in the fall may enable snapping turtles to lay their eggs earlier and provide their young an advantage over other species. Herpetologist Michael Dreslik said,“Generalists like the Snapping Turtle tend to be more adaptable. The added benefit from warmer temperatures could allow Snapping Turtles to gather more resources for larger eggs or larger clutches.”
The mechanisms by which warmer temperatures influence egg and clutch size are unknown. Turtles are ectotherms, thus metabolism and physiology are impacted by environmental conditions.
“Warmer temperatures increase metabolism, but could result in greater food availability and more efficient processing of the food. Warmer temperatures could also affect the physiology of embryo development,” said lead author Ashley Hedrick. “Alternatively, in the spring, increased metabolism before food is readily available may require females to divert energy from egg development.”
While rising temperatures are generally considered problematic for most species, they could play in favor of the Snapping Turtle.
The paper “The Effects of Climate on Annual Variation in Reproductive Output in Snapping Turtles (Chelydra serpentina).” is available online from the Canadian Journal of Zoology.
UBAP staff are part of the team that found a wild alligator snapping turtle in Illinois, the first one seen since 1984. Currently working as part of a reintroduction program, Chris Phillips found the turtle while trying to locate a radio-tagged individual they had released in the area.
UBAP staff Michael J. Dreslik and Jason P. Ross recently presented at the 2017 Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles. The meeting was held in Charleston, South Carolina from August 6th – 9th and has international attendance. At the meeting, they presented a poster on the effectiveness of passage gates along the Asian Carp Barrier and a co-authored oral presentation with a collaborator on the reproduction of Common Snapping Turtles which is in press in the Canadian Journal of Zoology.
Hedrick, A. R., H. M. Klondaris, L. C. Corichi, M. J. Dreslik. J. B. Iverson. The effects of climate on annual variation in reproductive output in Snapping Turtles (Chelydra serpentina). Oral Presentation.
Ross, J. P., C. Y. Feng, and M. J. Dreslik. Evaluating turtle passage gates using remote camera traps and visual encounter surveys. Poster Presentation. View Poster
ARC Lab members Ethan J. Kessler and Michael J. Dreslik received funding from The Nature Conservancy, Indiana to conduct surveying for the Alligator Snapping Turtle (Macrochelys teminckii). The surveys will be a combined effort of trapping and eDNA sampling in the Patoka and White River watersheds. The project also includes some proof-of-concept work for eDNA work at the southern Illinois release site. Survey work will commence this summer through fall.
Dreslik, M. J., C. E. Petersen, S. M. Goetz, J. D. Kleopfer, and A. H. Savitzky. Spatial ecology of the Timber Rattlesnake (Crotalus horridus) from the mid-Atlantic coastal plain.
Dreslik, M. J., J. A. Crawford, S. J. Baker, W. E. Peterman, and C. A. Phillips. Detection probability and capture yield of an imperiled species.
Baker, S. J., M. J. Dreslik, C. A. Phillips, and M. C. Allender. Impact of snake fungal disease on population viability.
Dreslik, M. J., C. E. Petersen, S. M. Goetz, J. D. Kleopfer, and A. H. Savitzky. Factors affecting the movements of Timber Rattlesnakes (Crotalus horridus) from the mid-Atlantic coastal plain. View Poster