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The increased public interest in amphibian conservation and the growing evidence of detrimental effects of habitat fragmentation on biological diversity (see Saunders et al., 1991 for a review) has prompted land managers to seek ways of managing amphibian populations at landscape scales. For example, principles of landscape ecology are now being used by avian ecologists to direct conservation efforts and design nature reserve systems (e.g., Robbins et al., 1989; Pearson, 1993; Flather and Sauer, 1996). Landscape ecology emphasizes landscape patterning, species interactions across landscape mosaics, and the change in these patterns and interactions over time (e.g., Gardner et al., 1987; Turner, 1989; Turner and Gardner, 1991; Forman, 1995). Central to landscape-scale studies of amphibians is an assessment of relevant spatial and temporal scales. Wetlands in the prairie pothole region (PPR) of eastern South Dakota provide breeding habitat for 11 frog and toad species (Naugle et al., this volume). Because wetlands are discontinuous habitats embedded within an upland matrix (Winter, 1988; Johnson and Higgins, 1997), amphibians here have clumped distributions with interactions that may produce metapopulations (Sjögren, 1991; Hanski and Gilpin, 1997). Metapopulations are susceptible to wetland losses that fragment habitat because subpopulations that go extinct must be recolonized by dispersing amphibians from nearby wetlands. Despite a 45% loss in wetland numbers (Johnson and Higgins , 1997), glaciated landscapes in eastern South Dakota have been less impacted by habitat fragmentation than elsewhere in the Midwest, where wetland losses exceed 90% (Tiner, 1984; Dahl, 1990; Leja, 1998). Wetland size and permanence in the PPR vary along a continuum from small, temporary and seasonal wetlands to large, semipermanent and permanent wetlands . Variable hydrologic cycles cause seasonal and semipermanent wetlands to go completely dry for 2 or more consecutive years. The abundance of wetland complexes and dynamic nature of the hydrologic cycle make eastern South Dakota an ideal landscape in which to study amphibian wetland use and to examine how use might change over time with fluctuating water conditions (following Lannoo, 1998a). Here, we introduce the potential role of landscape ecology in amphibian conservation, provide an interpretation of landscape analyses using real data on amphibian populations, and outline insights gained from this study that might enhance future landscape-level management decisions. Methods Survey Methodology We used call survey data collected in 1997–98 in eastern South Dakota (Naugle et al., this volume) to evaluate anuran habitat use in temporary, seasonal, and semipermanent (Stewart and Kantrud, 1971) wetlands. Male mating calls were recorded during nighttime auditory surveys at randomly selected wetlands positioned along roadside transect routes. The timing of surveys coincided with peak calling periods for amphibians in the northern Great Plains (see Fig. 47-2 in Naugle et al., this volume). We initially conducted call surveys at 1,496 wetland sites to obtain information on distributions of anurans over a large geographic region (Naugle et al., this volume). Survey methodology followed an established sampling protocol that has been extensively used to monitor amphibians (Hemesath, 1998; Johnson, 1998b; Mossman et al., 1998). Although call surveys enable researchers to evaluate large regional databases (Mossman et al., 1998; Knutson et al., 1999), some investigators (e.g., Kline, 1998) have indicated that call survey data may be a poor substitute for intensive survey work in a small number of wetlands. To minimize the probability of misclassifying occupied wetlands using call surveys, we considered the influences of species occurrence rates and distributions, survey timing, and weather conditions. In these analyses, we used six species—Woodhouse’s toads (Bufo woodhousii), Canadian toads (B. hemiophrys), American toads (B. americanus), Great Plains toads (B. cognatus), northern leopard frogs (Rana pipiens), and striped chorus frogs (Pseudacris triseriata triseriata or maculata)—that occurred in at least 90 of the original wetlands surveyed. Ranges for these six species were sympatric (see Fig. 47-1 in Naugle et al., this volume) in 13 eastern South Dakota counties (Fig. 26-1). Calling in all six species was recorded in the highest proportion of wetlands between 2100–0059 hr (Fig. 26-2). The wetlands included in analyses met the above criteria, were surveyed during the best weather 185 T W E NT Y- S I X Landscape Ecology DAVID E. NAUGLE, KENNETH F. HIGGINS, REX R. JOHNSON, TATE D. FISCHER, AND FRANK R. QUAMEN conditions (low winds [5 km/h] and water temperatures 10 °C), and were located more than 3,000 m apart. Local Habitat Measures The area (ha) of surveyed wetlands was estimated using a wetland geographic information system (GIS) that was constructed...

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