Strategic Communications and Marketing News Bureau

For now, Illinois’ imperiled eastern massasauga rattlesnakes retain their genetic diversity

CHAMPAIGN, Ill. — Habitat loss, habitat fragmentation and the loss of genetic diversity are the three main factors driving the extinction of many wild species, and the few eastern massasauga rattlesnakes remaining in Illinois have certainly suffered two of the three. A long-term study of these snakes reveals, however, that – despite their alarming decline in numbers – they have retained a surprising amount of genetic diversity.

The new findings are reported in the journal Copeia.

“Despite occurring in small, fragmented populations, eastern massasaugas in Illinois do not show genetic evidence of inbreeding,” said Illinois Natural History Survey postdoctoral researcher Sarah J. Baker, who led the new research.

The genetic analysis did reveal, however, the loss of several rare versions of genes over the course of the 10-year study, which ended in 2012. Such losses can signal the early stages of local extinction, Baker said.

In 2015, the U.S. Fish and Wildlife Service listed the eastern massasauga as a threatened species nationally. Massasaugas are endangered in Illinois.

A new study finds eastern massasauga snakes in Illinois have retained much of their genetic diversity despite population declines, habitat loss and fragmentation.

A new study finds eastern massasauga snakes in Illinois have retained much of their genetic diversity despite population declines, habitat loss and fragmentation.

The widespread conversion of prairie to row-crop agriculture and the construction of the Carlyle Lake dam in central Illinois were among the biggest assaults on massasauga populations in the state, said INHS herpetologist Michael Dreslik, a coauthor of the study.

“The lake was constructed as an impoundment of the Kaskaskia River in 1967 and flooded bottomland habitat,” he said. “The remaining massasaugas are now clustered in wet prairies containing crayfish burrow complexes that shelter the snakes. These represent the only remaining suitable habitat patches for them.”  

The construction of Carlyle Lake did not result in a genetic “bottleneck,” however, Baker said.

“Bottlenecks can occur when a large population is quickly reduced in size, causing a loss of genetic diversity,” she said.

Eastern massasauga rattlesnakes in Illinois have lost a few rare alleles, or versions of genes, a new study finds.

Eastern massasauga rattlesnakes in Illinois have lost a few rare alleles, or versions of genes, a new study finds.

Despite the positive findings, the snakes are likely to become locally extinct without significant intervention, the researchers said. According to a 2017 estimate, the largest subpopulation of wild massasaugas remaining in Illinois includes 26-69 snakes.

“Previous studies propose that a total population of at least 100 is required for short-term maintenance of genetic diversity, and a population of 1,000 is needed to ensure long-term conservation,” Baker said. “Conservation and management actions that can increase population size should be enacted as soon as possible to preserve the remaining genetic diversity and ensure the persistence of the species in Illinois.”

The INHS is a division of the Prairie Research Institute at the University of Illinois.

Editor’s notes:
To reach Sarah Baker, email sjbaker2@illinois.edu.  
To reach Michael Dreslik, email dreslik@illinois.edu.
The paper “Temporal patterns of genetic diversity in an imperiled population of the eastern massasauga rattlesnake (Sistrurus catenatus)” is available online and from the U. of I. News Bureau.
DOI: 10.1643/CG-17-682

Read Next

Life sciences Photo of Michael Ward standing in tall grass on a riverbank.

How are migrating wild birds affected by H5N1 infection in the U.S.?

Each spring, roughly 3.5 billion wild birds migrate from their warm winter havens to their breeding grounds across North America, eating insects, distributing plant seeds and providing a variety of other ecosystem services to stopping sites along the way. Some also carry diseases like avian influenza, a worry for agricultural, environmental and public health authorities. […]

Announcements Marcelo Garcia, professor of civil and environmental engineering at The Grainger College of Engineering.

Illinois faculty member elected to National Academy of Engineering

Champaign, Ill. — Marcelo Garcia, a professor of civil and environmental engineering in The Grainger College of Engineering, has been elected to the National Academy of Engineering.

Social sciences Male and female student embracing on the quad with flowering redbud tree and the ACES library in the background. Photo by Michelle Hassel

Dating is not broken, but the trajectories of relationships have changed

CHAMPAIGN, Ill. — According to some popular culture writers and online posts by discouraged singles lamenting their inability to find romantic partners, dating is “broken,” fractured by the social isolation created by technology, pandemic lockdowns and potential partners’ unrealistic expectations. Yet two studies of college students conducted a decade apart found that their ideas about […]

Strategic Communications and Marketing News Bureau

507 E. Green St
MC-426
Champaign, IL 61820

Email: stratcom@illinois.edu

Phone (217) 333-5010