Downstream effects on caddisfly larvae (Hydropsychidae and Brachycentrus spp.).

Abstract

The East Maple River was sampled for Hydropsychidae and Brachycentrus abundance downstream from a beaver dam for 6400 meters. The abundances were analyzed for changes related to downstream distance, current velocity, light availability and fine particulate organic matter. Hydropsychidae abundance was shown to increase with increasing downstream distance, current velocity, and light. The abundance decreased with increasing dry mass of FPOM, which is possibly due to uncertainty of how much of the dry mass is organic material available to the organism. Brachycentrus were not found at all in the East Maple, probably due to a combination of high temperatures and low velocities.