The Effects of Selective Logging on the Allochthonous Plant Litter in Low-Order Upper Michigan Streams

Abstract

Previous studies in the Pacific Northwest of the United States have demonstrated that clear-cutting riparian forests can detrimentally effect both physical and biological characteristics of streams. Conclusions from these studies, however, may not be applicable to systems with different biological communities, climate, topography and forest management. Additionally, few studies have rigorously examined the impact of riparian forest management on the dynamics of instream allochthonous plant litter, which is particularly important to the energy and nutrient budgets of low-order temperate streams. This study assessed the density and composition of allochthonous plant litter carried by water in low-order Upper Michigan that were either recently selectively harvested or older riparian forests. Plant litter samples were collected from seven sites several times during the summer of 1999 by deploying mesh traps into the streams for approximately 24-hour periods. There were no significant differences between treatments in the density or composition of allochthonous plant litter in the study sites, suggesting that selective logging may have little effect on the input of organic matter into streams. It is also possible, though, that my reference sites were not old enough to have returned to pre-harvest conditions and thus did not show a difference from recently harvested sites. Selective harvesting, however, has the potential to protect the allochthonous inputs to streams and the consumers that depend on this energy.