Linking productivity, Biodiversity and habitat of benthic stream macroinvertebrate communities:: Potential complications of worldwide and regional patterns

To assess potential complications of links between productivity, biodiversity, and habitat, we assembled published worldwide data on benthic stream macroinvertebrate communities covering (1) annual production (P); (2) annual production/biomass-rate (P/B); (3) number of taxa contributing to P (1313); (4) mean annual individual weight as a measure of organisms' size (S); and (5) mean annual discharge as a measure of habitat extent (Q), which enabled tests of the six hypothetical allometric relations and P alpha BDx, PaSx, P alpha Q(x), P/B alpha BD-x, P/B alpha S-x, P/B alpha Q(-x). The worldwide data provided equivocal support for these hypothetical relations, because the worldwide patterns were potentially obscured by various complications (e.g., continental BD-gradients, organic pollution, alien species). However, testing the hypothetical relations using less complicated, regional data sets provided scarcely better support for them.