Ecological Species Groups of Oak Ecosystems of Southeastern Michigan

Abstract

Abstract Ecological species groups were developed for oak forest ecosystems of southeastern Michigan that had been moderately disturbed. Species groups were determined from field observations and sample plot data arranged and analyzed in association tables. The groups were defined on the basis of species patterns of presence, absence, and coverage values along gradients of soil moisture and fertility. Thirteen ecological species groups were developed using 68 herbaceous and shrub species. Detailed descriptions of the relationships of the groups to soil moisture, soil fertility, and light conditions are presented. A continuum of groups from very dry to wet sites were identified. Some groups had a relatively broad range of soil moisture and fertility, whereas others were relatively narrow in their requirements. The groups were more easily differentiated along a soil moisture gradient compared to a soil fertility gradient. Most of the species within groups had similar ecological responses. There was a certain degree of overlap among the groups and usually more than one group occurred in any ecosystem. Despite disturbances caused principally by cutting, ecological species groups could nevertheless be constituted and were useful in identifying major and minor site differences. However, in such disturbed forests, it is recommended that they be used together with physiographic and soil attributes to estimate site quality or identify ecosystem types. For. Sci. 35(4): 1058-1074.