Broad spatial patterns of organisms are non-random and a growing literature suggests that spatial autocorrelation can be used to investigate their underlying mechanisms. Although exo- and endogenous mechanisms are responsible for such patterns, endogenous factors were rarely assessed in the past. Using spatial autocorrelation methods, we investigated if patterns of riverine invertebrates in 117 unimpacted sites scattered across the Mediterranean Basin were driven by exogenous (environmental) and/or endogenous (e.g. dispersal) mechanisms. We hypothesized that, after accounting for environmental effects, taxonomic groups with higher dispersal abilities will exhibit no spatial pattern, whereas groups with limited dispersal abilities will exhibit spatial patterns. We estimated dispersal abilities of each taxonomic group using 4 biological traits. Before and after accounting for environmental effects, we calculated the Moran index for each group and related it to the dispersal abilities. Spatial patterns of highly active disperses (Heteroptera, Coleoptera, and Odonata) were only explained by exogenous factors, whereas patterns of less active dispersers were explained by a combination of exogenous and endogenous factors (Crustacea, Ephemeroptera, Plecoptera, and Trichoptera) or by only endogenous factors (Mollusca). Our results suggest that endogenous factors should be included when analysing broad spatial patterns of organisms.