STUDENT CLOSE-UP

Assisting Amphibians

Note: This is an excerpt of a story published in the spring 2004 issue of Illumination, a magazine that showcases research, scholarship and creative achievement at the University of Missouri-Columbia. View Illumination online.

By Charlotte Overby

Two years ago, at the Thomas S. Baskett Wildlife Research Area — an MU wildlife research site since 1938 — doctoral student Tracy Green Rittenhouse launched a radiotelemetry tracking study of 39 spotted salamanders. Spotted salamanders are a six-inch woodland species with a slate-colored body and round yellow spots. They live out their lives breeding and laying eggs in shallow ponds and then migrating back into the forest for the rest of the year. Rittenhouse is only the second person to fit spotted salamanders with tiny transmitters. And for good reason: Attaching electronic beacons to small, slithery creatures isn’t easy. It involves anesthetizing each salamander, making an incision, and then placing the transmitter inside its body cavity.

It is, she admits, a slightly unsavory process. But it’s worth the effort: “We know quite a bit about their lives in the pond, but not much about what happens when they leave the ponds and head into the woods. We need to learn more about their terrestrial habitats.”

Learning more about the “dual life” of amphibians, meaning their survival both on land and in water, is the focus of Rittenhouse’s research under the direction of Ray Semlitsch, professor of biology at MU and forerunner of amphibian research since 1975. Today Semlitsch is one of only a handful of researchers dedicated solely to applied amphibian conservation issues, many of which concern the loss of essential aquatic and terrestrial habitats.

Rittenhouse says she enrolled at MU to study with Semlitsch, who is focusing his research on amphibians’ need for wetland habitats of all shapes and sizes. Many amphibian species thrive in shallow ponds the size of a football field, while some need little more than a ten-foot mushy spot in low-lying woods; either way, these small, scattered wetlands usually dry up for part of the year and are essential to amphibian survival and reproduction.

Semlitsch and his students are currently studying how amphibian offspring disperse among different wetlands and how they make use of the forests around the watery places. This differs from traditional approaches to amphibian research that concentrate mainly on the aquatic phase of the life cycle that is tied to one particular wetlands breeding area.

Rittenhouse began her study by selecting two ponds, one surrounded by woods and another bordered by a manmade grassland edge. After placing the radio-fitted salamanders into the ponds, she trudged out and recorded their movements each day for three months. As it turns out, obstacles matter to salamanders — even seemingly natural obstacles.

Rittenhouse found that those salamanders faced with crossing the bluestem, Indian grass and fescue-filled pasture, stayed put. “None of them walked more than two or three meters into the grassy field when they left the pond. They turned around. It was the first time we could really show that they can tell a difference between habitats,” she says. The spotted salamanders in her study, in fact, avoided the inhospitable habitat even when there was another suitable pond and ideal forest just 100 meters away. Rittenhouse is today expanding on her findings in a larger study on frogs located in the Daniel Boone Conservation Area near Hermann, Mo.

Again and again, Semlitsch and his students have found that the success or failure of amphibian populations depends not only upon the availability of such small isolated wetlands, but also on the ability of the vulnerable creatures to move through terrestrial habitats among them. Unfortunately these types of wetlands — the small ponds and seasonally flooded spaces that are most critical for amphibians’ survival — are least likely to be protected by law.

“The regulatory landscape favors larger wetlands over smaller ones, even though the ecological landscape presents a different view: Larger doesn’t mean better,” says Semlitsch.

Archives | Comments | Home

SUBSCRIPTIONS
Subscribe | Change Your Address | Unsubscribe

Copyright © 2007 — Curators of the University of Missouri
DMCA and other copyright information.
All rights reserved. An equal opportunity/ADA institution.
Published by the Mizzou Alumni Association
Questions? Comments? E-mail comments@mizzoualumni.org

Last Update: November 15, 2007