Influence of Local, Landscape, and Regional Variables on Sedge and Marsh Wren Occurrence in Great Lakes Coastal Wetlands

Abstract

We determined the influence of habitat, landscape, geographic, and climate variables on Sedge Wren (Cistothorus platensis) and Marsh Wren (C. palustris) occurrence in 840 coastal wetland survey points throughout the Great Lakes. Variables included surrounding land use and configuration out to 2000 m; latitude; longitude; temperature; precipitation; and vegetation characteristics within 100 m. Classification trees predicted Sedge Wren occurrence at points in the western Great Lakes with < 11 km of roads within 1000 m. Emergent herbaceous wetland within 500 m, woody wetland within various distances, and sedge within 100 m were also positively associated with Sedge Wren occurrence. Marsh Wren occurrence was predicted at points in the southern Great Lakes with < 42% developed land within 500 m. Emergent herbaceous wetland within 500 m, cropland within various distances, and cattail within 100 m were also positively associated with Marsh Wren occurrence. Our results suggest limiting development around wetlands is important for conserving these bird species throughout Great Lakes coastal wetlands. Landscape-scale land cover variables are easily obtainable and significantly increase our ability to predict occurrence of these species across a broad geographic scale.