Bird community response to changes in wetland extent and lake level in Great Lakes coastal wetlands

Session: Great Lakes Coastal Wetlands: Innovative Research to Improve Restoration (3)

Tara Hohman, UW-Green Bay/Bird Studies Canada, [email protected]
Robert Howe, UW-Green Bay, [email protected]
Amy Wolf, University of Wisconsin Green Bay, [email protected]
Erin Giese, UW-Green Bay's Cofrin Center for Biodiversity, [email protected]
Douglas Tozer, Bird Studies Canada, [email protected]

Abstract

Coastal wetlands in the Laurentian Great Lakes undergo frequent, sometimes dramatic physical changes at varying spatial and temporal scales due to local weather conditions, seasonal growth and senescence of vegetation, and fluctuating lake levels. Changes in water levels and the subsequent changes in the juxtaposition of vegetation and open water greatly influence biota that use coastal wetlands. Several regional studies have shown that changes in vegetation and lake levels lead to predictable changes in the composition of Great Lakes coastal wetland bird communities. We report new findings of wetland bird community changes at a much larger scale, covering the entire Great Lakes. Populations of marsh-obligate bird species vary in response to several hydrologic and habitat variables, including percent wetland cover, interspersion of water and vegetation, and wetland type. Our results 1) identify quantitative wetland attributes that are predictably associated with lake level changes; 2) illustrate how lake level variation affects different marsh-obligate bird species; and 3) determine where dynamic bird-habitat interactions are most pronounced within the Great Lakes basin. Understanding the effects of water level changes on birds in Great Lakes coastal wetlands will help policy makers make effective decisions about wetland protection, management, and restoration.