Local environmental variables are key drivers of ant taxonomic and functional beta-diversity in a Mediterranean dryland.

ABSTRACT

The decomposition of beta-diversity (ß-diversity) into its replacement (ßrepl) and richness (ßrich) components in combination with a taxonomic and functional approach, may help to identify processes driving community composition along environmental gradients. We aimed to understand which abiotic and spatial variables influence ant ß-diversity and identify which processes may drive ant ß-diversity patterns in Mediterranean drylands by measuring the percentage of variation in ant taxonomic and functional ß-diversity explained by local environmental, regional climatic and spatial variables. We found that taxonomic and functional replacement (ßrepl) primarily drove patterns in overall ß-diversity (ßtot). Variation partitioning analysis showed that respectively 16.8%, 12.9% and 21.6% of taxonomic ßtot, ßrepl and ßrich variation were mainly explained by local environmental variables. Local environmental variables were also the main determinants of functional ß-diversity, explaining 20.4%, 17.9% and 23.2% of ßtot, ßrepl and ßrich variation, respectively. Findings suggest that niche-based processes drive changes in ant ß-diversity, as local environmental variables may act as environmental filters on species and trait composition. While we found that local environmental variables were important predictors of ant ß-diversity, further analysis should address the contribution of other mechanisms, e.g. competitive exclusion and resource partitioning, on ant ß-diversity.