02241nas a2200253   4500008004100000245007600041210006900117300001300186490000800199520145100207653001901658653001901677653001701696653002301713653001801736100001801754700001701772700001701789700002401806700001601830700001801846700001701864856010601881       2007                        eng d00aStream insect occupancy-frequency patterns and metapopulation structure0 aStream insect occupancyfrequency patterns and metapopulation str  a313 -3210 v1513 aAn 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.10aaquatic insect10aCore-satellite10aDistribution10aSampling intensity10aspatial scale1 aHeatherly, T.1 aWhiles, M.R.1 aGibson, D.J.1 aCollins, Scott., L.1 aHuryn, A.D.1 aJackson, J.K.1 aPalmer, M.A.  uhttp://129.130.186.12/content/stream-insect-occupancy-frequency-patterns-and-metapopulation-structure