Stream insect occupancy-frequency patterns and metapopulation structure

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TitleStream insect occupancy-frequency patterns and metapopulation structure
Publication TypeJournal Article
Year of Publication2007
AuthorsHeatherly, T, Whiles, MR, Gibson, DJ, Collins, SL, Huryn, AD, Jackson, JK, Palmer, MA
ISBN Number0029-8549
Accession NumberARC481
KeywordsAquatic insect - Core-satellite - Distribution - Sampling intensity - Spatial scale

An understanding of the distribution patterns of organisms and the underlying factors is a fundamental goal of ecology. One commonly applied approach to visualize these is the analysis of occupancy-frequency patterns. We used data sets describing stream insect distributions from different regions of North America to analyze occupancy-frequency patterns and assess the effects of spatial scale, sampling intensity, and taxonomic resolution on these patterns. Distributions were dominated by satellite taxa (those occurring in ≤10% of sites), whereas the occurrence of core taxa (occurring in ≥90% of sites) determined the overall modality of occupancy-frequency patterns. The proportions of satellite taxa increased with spatial scale and showed positive relationships with sampling intensity (r 2=0.74–0.96). Furthermore, analyses of data sets from New York (USA) showed that generic-level assessments underestimated the satellite class and occasionally shifted occupancy-frequency distributions from unimodal to bimodal. Our results indicate that, regardless of species- or generic-level taxonomy, stream insect communities are characterized by satellite species and that the proportion of satellite species increases with spatial scale and sampling intensity. Thus, niche-based models of occupancy-frequency patterns better characterize stream insect communities than metapopulation models such as the core-satellite species hypothesis.

Short TitleStream insect occupancy-frequency patterns and metapopulation structure