Local and Landscape-Level Factors Influencing Black Tern Habitat Suitability

Abstract

Wetlands throughout eastern South Dakota were surveyed (1995-97) for foraging and nesting black terns (Chlidonias niger) to evaluate local and landscape factors influencing habitat suitability. We surveyed 834 randomly selected, semipermanent, and seasonal wetlands that were stratified by physiographic domain, wetland density, and wetland surface area. A discriminant function model was used in a geographic information system (GIS) to classify habitat suitability of all semipermanent wetlands in eastern South Dakota. We calculated number of suitable, protected wetlands by combining wetlands with easement and feetitle tracts in the GIS. Black terns nested in 7.8% and foraged in an additional 17.9% of semipermanent wetlands. Significant variables in the discriminant function were wetland area, total semipermanent wetland area within the wetland complex, and grassland area in the upland matrix. Black terns were an area-dependent species that occupied large (x̄ = 18.9 ha) wetlands located within high-density wetland complexes. Black terns typically occurred in wetlands within landscapes where

Population Decline of Black Terns in Wisconsin: A 30-Year Perspective

“…Naugle (1997) reported small (6.5 ha) marshes, within a mixture of large and small wetlands, being used by Black Terns in high-density wetland landscapes in South Dakota. In a subsequent South Dakota study, the mean size of wetlands used was 18.9 ha (Naugle et al 2000). Researchers report that nesting typically occurs in water depths ranging from 0.5 m to 1.2 m (Currier 2000), but several studies have found it to be less (Dunn and Agro 1995).…”

“…or heath bogs (Peck and James 1983). Vegetation structure rather than species composition dictated suitability of nest substrates in eastern South Dakota (Naugle et al 2000).…”

Migrating and breeding bird use of restored shallow lakes in Iowa

“…Several sources have identified the importance of landscape-level features on wetland use by waterbirds (Naugle et al 2000, Beatty et al 2014. In particular, waterfowl may use a variety of wetland types during spring migration, as a single wetland may not provide the necessary resources required by different species (Pearse et al 2011, Naugle et al 2001).…”

“…Additionally, other studies have found average local flight distances of about 3 to 5 km for Mallards (Link et al 2011, Beatty et al 2014 and Northern Pintails (Anas acuta; Pearse et al 2011), and several landscape characteristics have been shown to influence waterbirds at these spatial scales (Elphick 2008, Naugle et al 2000). …”

“…Total wetland area within the surrounding landscape. Migrating waterbirds may choose stopover locations at a landscape scale (Naugle et al 2001, Beatty et al 2014, and the presence of wetland complexes may be a good indicator for some species (Naugle et al 2000, 2001, Beatty et al 2014). …”