Amphibian Distributions In Agricultural Landscapes: Responses At Multiple Spatial Scales
Melinda G. Knutson, USGS Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Rd., La Crosse, WI 54603; (608) 781-6339; FAX (608) 783-6066; mknutson@usgs.gov
Can amphibians and agriculture coexist? Recent research identifies components of the agricultural landscape needed to support amphibian populations. Knowledge of these habitat associations at local as well as regional spatial scales will help identify appropriate conservation strategies. For example, regional analyses indicate that most species can be reliably grouped into broad habitat categories, such as grassland associates and forest associates, confirming the general observations of herpetologists. However, specific habitat associations can vary from state to state. We found that most amphibians had negative associations with agriculture in Iowa, while amphibians in Wisconsin were positively associated with agriculture. In our study of farm ponds, we found that amphibians were more associated with characteristics of the breeding pond than with landscape variables. This is good news for amphibians because breeding pond characteristics such as water quality, vegetation, and the presence or absence of fish are more subject to management than is the composition of the landscape within 5 miles of the breeding pond, for example. Interested landowners have an opportunity to conserve or restore high quality amphibian breeding habitats, but they also need to be aware of non-breeding season habitat requirements. As suburbs encroach on agricultural land and road density increases, conserving high quality amphibian habitats will require careful consideration of breeding and wintering habitat and the linkages between them. This paper summarizes important components of the agricultural landscape for amphibians.