Understanding species richness variation among local communities is one of the central topics in ecology, but the complex interplay of regional processes, environmental filtering and local processes hampers generalization on the importance of different processes. Here, we aim to  unravel drivers of spider community assembly in temperate forests by analyzing two independent data sets covering gradients in elevation and forest succession. We test the following four hypotheses: (H1) Spider assemblages within a region are limited by dispersal; (H2) Local environment has a disproportionate influence on species composition; and (H3) resources and (H4) biotic interactions both affect species richness patterns. Spider data were collected by pitfall traps in two independent projects within a region along elevation and canopy cover gradients.

Spiders were collected by pitfall traps. Morphological measurements were taken from literature or done by the authors.