Birds in depressional forested wetlands: Area and habitat requirements and model uncertainty

Abstract

Forested wetlands are important habitat for many bird species, but data about area and habitat relationships of birds in depressional (i.e., non-riverine) deciduous forested wetlands are scarce. Depressional forested wetlands are often surrounded by larger, continuous patches of upland forest, and it is not clear whether this surrounding forest should be considered part of the forested wetland. To contribute regional data to this question, we sampled birds and vegetation in depressional forested wetlands in southern Michigan, USA. Results indicated that the wetland per se should not be considered separate from the surrounding forest because forest area and forest characteristics were the most important predictors of richness and abundance of wetland-associated birds. Conversely, wetland area and wetland characteristics were important for some upland species. Because spatial clustering and model selection uncertainty are often encountered by wetland scientists, we describe analytical methods used to deal with these problems.