Patterns of patch use and distribution of hydropsychid caddisflies (Trichoptera) in the Maple River catchment, Northern Michigan.

Abstract

Species and size distributions of larval hydropsychid caddisflies were examined at the following spatial scales: 1) between streams, 2) longitudinally from upstream to downstream within the same stream, 3) among different microhabitats within a reach, and 4) between stones of varying roughness values. Densities of Hydropsyche betteni and Ceratopsyche sparna were different between streams. Densities within a reach of a stream were significantly different across five microhabitats for H. betteni, Cheumatopsyche, Ceratopsyche slossonae, and Ceratopsyche sparna, but were not for Ceratopsyche morosa. Densities in Cladophora glomerata patches were higher than in biofilm patches; however, overall percent retreat construction materials exhibited a weaker trend of Cladophora usage. This comprehensive study is a foundation for examining patch use mechanisms in Northern Michigan ecosystems.