Effects of edges on plant communities in a managed landscape in northern Wisconsin

dThe effects of edges on plant communities following clearing of coniferous forests in the Great Lakes region had not been previously examined. This study quantified plant responses to six recent (8-12 years old) clearcut edges adjacent to jack pine (Pinus banksiana) and red pine (Pinus resinosa) plantations. Percent cover of each understory plant species was estimated within 10 randomly placed plots at 19 distances along a 240 m transect extending from the clearcut, across the edge, and into the forest interior. Species richness was significantly higher in the jack pine stands (n=10.2-12.2) than in the red pine stands (n=6.1-9.1, p <0.05). Among the 67 species detected. 18 and two species were unique to the jack and red pine stands, respectively. Detrended correspondence analysis (DCA) and abundance band ratios were used to divide species into functional groups according to their distributions along the transect. A depth-of-edge influence was determined for species that showed a clear preference for the clearcut, interior, or edge habitat. Compositional gradients were also reflected in a DCA of distance sampled based on species abundance. Finally, regression models were developed to predict diversity from topographic. structural, and stand composition variables. A synthesis model is presented to describe plant species distributions across forest/ clearcut edges, in this model, edge species patterns can show stronger effects on one side of the forest/clearcut edge than the other side. (C) 2001 Elsevier Science B.V. All rights reserved.