Habitat connectivity and regional heterogeneity represent two important regional processes likely to affect biodiversity and ecosystem functioning across different spatial scales. We performed a 3 x 2 factorial design experiment to investigate the effects of both processes and their interaction on artificial pond communities of freshwater invertebrates at the local (α), among-community (β), and regional (γ) scales.
Results/Conclusions
Despite strong expectations that the effects of connectivity would depend on levels of regional heterogeneity, no significant interaction was found for species richness, Simpson diversity, or functional diversity (FD) at any spatial level. While connectivity had a significant effect on local richness, it had no effect on local Simpson nor functional diversity, raising questions about the ecological relevance of such an increase in local richness. Furthermore, connectivity significantly reduced among-community Simpson diversity, and nearly significantly reduced among-community richness. Conversely, heterogeneity significantly enhanced among-community species richness and Simpson diversity. The major role of connectivity in ecological communities seems to be as a homogenizing force. Conversely, heterogeneity largely acts as a force maintaining diversity between communities. Despite strong expectations to the contrary, these two factors seem to exert their effects independently of one another.
