Rising temperatures could benefit the Snapping Turtle.

snapping turtle Photo by Jason P. Ross

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.


Corresponding author: J.B. Iverson email:
To reach Ashley Hedrick, email arhedri11@gmail.com
To reach Michael Dreslik, email dreslik@illinois.edu
Photo by Jason P. Ross

 

 

Midwest Fish and Wildlife Meeting

UBAP herpetologist Sarah Baker co-organized a symposium “Advances and Challenges in Amphibian and Reptile Conservation and Management” and presented “Impact of Snake Fungal Disease on Population Viability” at the 78th Midwest Fish and Wildlife Conference in Milwaukee, WI. Jan 28-31.

Student Kelsey Low presented a poster on “Ranavirus Effects on Body Condition and Growth of Developing Amphibians in Created Wetlands”

Monitoring the mussels of the Kishwaukee River

Mussels are often referred to as “the livers of the rivers” because they filter materials from their environment. Freshwater mussels are also among the most imperiled groups of organisms in the world.

grubbing for mussels
snorkeling for mussels
mussels being brought in for measurement
bags of mussels
measuring and marking mussels
Hallprint tag on mussel
mussels awaiting their return
mussels being returned

The Kishwaukee River basin in northern Illinois remains one of the most mussel-rich resources in the state. In 2012, the Urban Biotic Assessment Program (UBAP) began studying the fishes, reptiles, amphibians, and mollusks of the Kishwaukee River along the Illinois Tollway I-90 overpass. In 2015 UBAP began a longterm monitoring program of the mussel population at the site. Each August, a team of researchers from INHS, IDNR, and local land management agencies descends on the same location and intensively samples the mussels in the area over the course of a week.

We arrived at the site around 8:30 and began unloading and setting up all of the gear needed for the day. A group of 20 biologists and land managers eagerly grabbed sampling bags, donned wetsuits, waders, snorkels and masks and each claimed their 10m stretch of the river.

When given the signal, we plunged our heads into the swift moving, 70F water to begin locating every mussel we could in our stretches of river and placing them in mesh bags attached to our waists. Much musseling is done by grubbing – shoving ones hands into the sediment and feeling around for mussels, which feel a bit like smooth rocks that hold on in the gravel with a fleshy foot. For some in the group, this was their first time musseling, and finding their first mussels was exhilarating.

After 30 minutes of sampling, we brought our bags of mussels back to the base station. Here, under the bridge with its constant rumble of vehicles speeding by, numbered tags were glued to each mussel. Some of the mussels also had a Passive Integrated Transponder (PIT) tag glued to their shell, which will enable them to be detected in the future without being removed from the river. Malacologists identified, measured, sexed, and aged each mussel before putting it back in its bag to be returned to its place in the river.

We continued these sampling sessions until the entire project area had been sampled. Over the lifetime of this project, thousands of mussels will be marked and measured. Many of the mussels we encountered had been marked in previous years, which will enable the scientists to document growth and survival over time as well as movement within the river.

As we left the site on the last day, we all looked forward to returning next year and hopefully finding those mussels and many new ones.

UBAP staff presents at Ecological Society of America

UBAP Ornithologist Anastasia Rahlin presented a poster at the Ecological Society of America conference held in Portland, Oregon from August 6th-11th. The poster reported on the environmental DNA research being conducted in collaboration with Mark Davis and Matthew Niemiller to collect presence-absence data on cryptic rails in Northern Illinois. The project is testing environmental DNA for bird detection and comparing it to traditional playback surveys.

Rahlin, A.A., M.A. Niemiller, and M.A. Davis. Using environmental DNA sampling methods to determine cryptic wetland bird occupancy in Illinois.

 

View poster

UBAP staff present at Biology of the Snakes Conference

Members of the Urban Biotic Assessment Program, Michael J. Dreslik and Sarah J. Baker, recently attended and presented at the Biology of the Snakes 2017 Conference in Rodeo New Mexico.  They gave two oral and two poster presentations.

Oral Presentations
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.

 

Poster Presentations
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

Funding received to survey the Alligator Snapping Turtle

UBAP staff 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.

UBAP staff mentor intern from the National Great Rivers Research & Education Center (NGRREC) 2017 Intern Program

Members of the Illinois Natural History Survey’s Urban Biotic Assessment Program hosted and advised an intern from the National Great Rivers Research & Education Center (NGRREC) 2017 Intern Program this summer. The intern worked on mapping the spread, determining geometric morphometrics, and genetics of a novel invasive species in the Corbicula genus. They attended the 2017 Annual NGRREC Intern Symposium from 31 July to 1 August 2017.

Presentations:

Reasor, E., S.A. Douglass, J.S. Tiemann, and M.A. Davis. Alien Invaders: Assessing the spread, genetics, and shape of a novel invasive clam.

Posters:

Reasor, E., S.A. Douglass, J.S. Tiemann, and M.A. Davis. Alien Invaders: Assessing the spread, genetics, and shape of a novel invasive clam.

 

UBAP staff present at Turtle Survival Alliance

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

UBAP ecologist accepts position at University of Alabama, Huntsville

UBAP ecologist Matthew Niemiller accepted a faculty position at the University of Alabama, Huntsville where he will return to his research in cave biology. Matt received his M.S. in Biology from Middle Tennessee State University and a Ph.D. in Ecology and Evolutionary Biology from the University of Tennessee-Knoxville dissertation topic “Evolution, Speciation, and Conservation of Amblyopsid Cavefishes.” While with UBAP, Matt was responsible for accoustic monitoring of bats in the Chicagoland area. We wish him well and look forward to continued collaboration.

Follow his research here:

http://www.speleobiology.com/cavebiolab/