Snake Studies to Offer Insights into Ecosystem Health

FAYETTEVILLE, Ark. — Researchers studying rattlesnakes in the Arkansas Ozarks have a unique opportunity to study the “before” and “after” changes in ecosystems caused by forest management practices.

Steve Beaupre, associate professor of biological sciences at the University of Arkansas, and graduate student Lara Douglas will be studying the effects of different land clearing and burning treatments on plants, insects, small mammals and rattlesnake growth and behavior in the Madison County Wildlife Management Area in Northwest Arkansas.

The forest area in question grew from a clear-cut nearly 100 years ago, and the clearing coupled with fire suppression has created a canopy of trees all of similar age that shade out native plants and grasses from the forest floor. The small mammals that live within the forest depend upon acorns for forage - and the rattlesnakes eat the squirrels and mice that consume the acorns.

“The dynamics of the system for the snakes are tied to the acorns,” Beaupre said. His previous research on rattlesnake physiology has shown that the snakes eat more, reproduce more, get fatter and grow longer in good acorn years than they do when acorns are scarce.

Beaupre and Douglas are working with the Arkansas Game and Fish Commission (AGFC), which has decided to use some different experimental treatments to try to restore the forest to a more dynamic ecosystem. To do this, the AGFC has planned two different types of cuts and burns at different sites in Madison County - one a clear cut and “hot” burn, the second a thinning cut and “cool” burn. They will have three different plots that get each treatment for a total of six plots.

Beaupre and Douglas will examine plant and animal populations at these sites and at six control sites where no cuts or burning will occur. Because of their relationship with the AGFC, the researchers were able to begin collecting data on the plants, insects, mammals and snakes this summer before the cuts and burns take place. This offers them a unique opportunity to see what an ecosystem looks like before and after the application of common forest management practices.

The reason for rattlesnake research is simple and important: Individual snakes respond quickly to environmental change.

“Snakes are really sensitive to short-term changes in small animal populations,” Beaupre said. Their bodies respond within a few months to an increase or decrease of food animals in the area. Although it is useful for research, this sensitivity could be the downfall of the timber rattlesnake in degraded forest ecosystems, especially those that are dependent upon acorn crops.

“If we have several really bad years in a row, we’re going to lose the population,” Beaupre said.

The local demise of rattlesnakes may not sound like a bad idea to some people, but Beaupre points out that rattlesnakes keep squirrel, mouse and rat populations in check, each animal eating up to dozens per year. If the snakes disappear, the delicate balance between the reptile and the mammals it eats would forever be lost.

This summer, Douglas is out in the field almost daily, surveying the plant life to estimate the number and density of species, catching insects on sticky traps and laying pre-baited trap grids for small mammals. This will help her develop estimates for the population density and diversity of the forests as they currently exist. She also will start identifying rattlesnakes for radio tagging. This information will provide the background for the changes to come during the cuts and burns.

“This is a unique opportunity. Not many studies like this are able to start ahead of a fire,” she said.

The researchers also will use background data from Beaupre’s ongoing rattlesnake studies to get a clear “before” picture of ecological health. Beaupre studies different rattlesnake populations in the Madison County Wildlife Management area using small finger-sized radio telemetry devices surgically placed in the body cavity of the snake. These devices allow the researchers to track the location and movements of the snakes, and even record their body temperature, Douglas said. Then they can find them in the field and observe their behavior.

Snakes make good models for studying behavioral and physiological ecology because their behaviors are easy to see: A foraging snake holds its head differently from a resting snake, and snakes seeking mates are found in different positions and locations than resting or foraging snakes. Also, researchers can tell when a snake has eaten by the telltale bulge in its otherwise lithe body.

Tracking the changes that take place in these animals will help researchers understand the bigger picture.

“If we understand how individuals are affected by environmental change, then we can predict what might happen in the future and assess the potential environmental impact of certain changes,” Beaupre said.