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Farm ponds as critical habitats for native amphibians

CHAPTER 5
Agricultural Land Uses are not Associated with Genetic Damage or Malformations in Frogs in Southeastern Minnesota

by

Bart L. Bly and Mark B. Sandheinrich
University of Wisconsin–La Crosse
Department of Biology
1725 State Street
La Crosse, Wisconsin 54601

Dean A. Jobe
Microbiology Research Laboratory
Gundersen–Lutheran Medical Center
1836 South Avenue
La Crosse, Wisconsin 54601

Melinda G. Knutson and Brian R. Gray
U.S. Geological Survey
Upper Midwest Environmental Sciences Center
2630 Fanta Reed Road
La Crosse, Wisconsin 54603

Abstract
Flow cytometry (FC) is a laboratory method that can be used to indicate genetic damage in amphibians. It is useful for evaluating sites with high rates of amphibian malformations or sites exposed to contaminants or other stressors. We used FC to compare the effects on amphibians of different types of agricultural land uses surrounding breeding ponds in southeastern Minnesota. Exposed ponds were surrounded by grazed grassland or row crop agriculture and received more fertilizers, pesticides, and animal wastes than the reference ponds, represented by natural wetlands and nongrazed grasslands. Amphibian metamorphs from reference and exposed ponds were examined for malformations and blood samples were analyzed with FC. We found no significant differences in amphibian genetic integrity or malformations between the reference and exposed ponds. Malformations were rare, but were observed in both the reference and exposed ponds.

Keywords: amphibian, agriculture, farm pond, flow cytometry, genetic damage, malformation