Broad-scale hypotheses do not account for species richness patterns of Central American mayflies

Abstract

I performed an exploratory analysis of four broad-scale hypotheses (area availability, energy availability, habitat heterogeneity and geometric constraints) for changes in species richness over Central American mayfly species, and compared their outcomes at different taxonomic levels. I employed an eigenvector-based spatial filtering to control spatial autocorrelation effects and conducted multiple spatial eigenvector regressions to identify the strongest predictors of species, genus and family richness. The usefulness of higher-taxa as surrogates for species richness was assessed by Pearson correlations. Mayfly species richness is characterized by a patchy pattern. None of the variables accounted for observed patterns. Only area availability was an effective predictor of mayfly genus and family richness, although both habitat heterogeneity and energy presented marginal effects on genus richness. I did not observe any relationship between species and higher-taxa richness. Broad-scale hypotheses did not explain species richness patterns of mayflies, which instead can be explained by interactions among studied variables and spatial structure.