Constructed farm ponds represent significant breeding, rearing, and overwintering habitat for amphibians in the Driftless Area Ecoregion of southeastern Minnesota, western Wisconsin, and northeastern Iowa, a landscape where natural wetlands are scarce. Despite intensive agricultural use adjacent to the ponds, these ponds harbor an abundance of frogs and toads. This region contains thousands of farm ponds constructed with cost-sharing dollars from the U.S. Department of Agriculture and the states.

The primary functions of farm ponds are to prevent soil erosion and create wildlife habitat, yet no studies have been conducted to determine how the ponds benefit wildlife.

We asked the following questions:

1. How are measures of amphibian individual, population, and community health associated with land uses surrounding the pond, such as row crops, grassland, and grazed grassland?
2. Are measures of amphibian individual, population, and community health more associated with surrounding landscape features or within-pond characteristics? (Figure 1)
3. What design features associated with a pond (size, depth, and vegetation) will maximize wildlife benefits?

Our goal was to identify farm management practices that lead to sustainable amphibian populations, high diversity, and low incidence of deformities. We are also developing a guide to the design, construction, and management of farm ponds for use by contractors, private landowners, and state or federal agencies

Weather conditions during the 2000 field season were dry in May, followed by heavy rainfall in late May through July. In 2001, steady April and May rains led to wet conditions early in the season, followed by a summer drought. We were fortunate to be able to study the same 40 ponds in both seasons.

The blue-spotted salamander (Ambystoma laterale) was identified at a single natural wetland. We observed high abundances of the American toad, eastern gray treefrog, and green frog at many ponds.

Six species of snakes and two turtle species were observed at the ponds over the 2 years of the study (Figure 4). The common garter snake (Thamnophis sirtalis) was the most frequently encountered reptile (18 ponds), followed by painted turtles (Chrysemys picta) (11 ponds).

One hundred species of birds were observed at the ponds (Figure 5). The song sparrow (Melospiza melodia) was the most frequently observed bird species (40 ponds), followed by the red-winged blackbird (Agelaius phoeniceus; 34 ponds), common yellowthroat (Geothlypis trichas; 30 ponds), and the American robin (Turdus migratorius; 25 ponds). For pictures of the bird species link to
http://www.mbr-pwrc.usgs.gov/id/framlst/infocenter.html.

Eighteen species of mammals were observed, with the raccoon (Procyon lotor) as the most commonly observed mammal (34 ponds), followed closely by the white-tailed deer (Odocoileus virginianus; 33 ponds; Figure 6). Five species of fish were identified from the ponds, with brook stickleback (Culaea inconstans) the most frequently observed (6 ponds; Figure 7). A wide variety of invertebrate taxa were observed in the ponds (Figure 8). Midge larvae (Order=Diptera), crawling water beetles (Order=Coleoptera), and water boatmen (Order=Hemiptera) were the most common invertebrate taxa observed. Our invertebrate sampling concentrated on potential amphibian larval predators and snails and was not a comprehensive inventory of all invertebrates in the ponds.

Water quality characteristics, such as water temperature, pH, dissolved oxygen concentration, conductivity, turbidity, chlorophyll-a, nitrogen (nitrate+nitrite), and total phosphorus, can directly (e.g., anoxia) and indirectly (e.g., food web effects, development of noxious algae, etc.) affect amphibian survival, growth, and reproduction; therefore, we monitored for these factors.
At each pond, we measured water clarity (turbidity, NTU), dissolved oxygen (DO, mg L^-1), conductivity (mmhos cm^-1), and water temperature (C), as well as total nitrogen (TN) and total phosphorus (TP) estimates (Table 1).