Area and habitat relationships of birds in Great Lakes coastal wet meadows

Although relationships of birds to patch area and habitat characteristics have been dominant themes in avian ecology over the past few decades, relatively little is known about these relationships in wetland-dominated landscapes of the Great Lakes coastline. During 1997 and 1998, we surveyed birds and measured habitat characteristics along transects in wet meadows associated with the northern Lake Huron shoreline (NLHS) in the Upper Peninsula of Michigan. Using a suite of multivariate techniques, we related abundance and presence/absence of individual species to wet meadow area and habitat characteristics. Nine species were positively associated with increasing wet meadow area, which underscores the importance of large wetlands to avian conservation in the region. Bird variables also were related to habitat characteristies. Higher values of bird variables were generally associated with a suite of characteristics: more robust and dense grass/sedge vegetation, structural diversity in the horizontal and vertical planes, and increased frequency of willow shrubs. Individual species that require particular aspects of these characteristics for nesting or foraging were associated with principal components containing those aspects. In the NLHS, large wet meadows that possess these characteristics would support the greatest diversity and benefit the majority of species. However, conservation efforts that focus only on these traits will not be sufficient for all species because habitat requirements for some species are very specific (e. g., open water for mallard), and for others, habitat preferences may change from year to year in response to lake-level changes. While our results provide important insights, continued research is needed to further the successful conservation and management of birds in Great Lakes coastal wetlands.