Large woody debris (LWD) has long been recognized as an essential component of aquatic ecosystems that provide a substrate for the accumulation of organic and inorganic matter and habitat for vertebrates and invertebrates. Macroinvertebrate communities are strongly influenced by their physical and chemical surroundings; both of which reflect land use. As part of a larger project to develop a biological assessment program for non-wadeable rivers, we compared macroinvertebrate community composition on natural log substrates in rural and urban rivers in southwest Michigan. In order to compare differences in water quality between and within rivers we used logs of two hardwood species, white oak (Quercus alba) and red maple (Acer rubrum), to normalize differences in available habitat. Logs were placed in the water column using rebar and nylon rope and were sampled regularly by removing an individual log, placing it into a bucket and gently removing macroinvertebrates with a pressure sprayer. We also compared colonization of artificial substrates with that of natural, wood substrate in an attempt to establish an accurate and cost-effective means of assessing non-wadeable rivers across a gradient of anthropogenic disturbance. Preliminary data will be reported.
Keywords: non-wadeable rivers, biological assessment
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA