Colonization by lentic macroinvertebrates:: Evaluating colonization processes using artificial substrates and appraising applicability of the technique

Our objectives were to describe the patterns of colonization of lentic macroinvertebrates on artificial substrates and to evaluate how this information can then be used to effectively and efficiently sample macroinvertebrates in vegetated littoral zones of lakes. Colonization of taxa in terms of both richness and density generally followed a Michaelis-Menton saturating curve with an initially rapid increase in densities up to a plateau within a short period of time (<8 days). We propose that this initial colonization is due to random encounters with the substrate and that the plateau represents a balance between immigration and emigration. Accordance with the saturating colonization curve improved with increasing densities of individuals. As a whole, the spatial pattern of colonization by orders of macroinvertebrates became more aggregated with time, indicating that true random encounter colonization occurs mainly in the early stages, and consequently, this is the time when sampling should best represent relative abundance. In addition, we found that invertebrate colonists of the substrata were concordant with prey items in the guts of rainbow trout (Oncorhynchus mykiss), a facultative benthivore.