Multiscale spatial dependency of small mammal diversity patterns and their determinants

Abstract

Animals perceive their ecosystems at multiple spatial scales such that the pattern–process relationships that determine their ecological and evolutionary opportunities are also spatially variable. Understanding how spatial scale impacts our observations of ecological and evolutionary patterns and processes is therefore crucial for effective biodiversity management. In this study, using a comprehensive dataset of small mammals from primary field surveys supplemented with literature data across Kenya, we investigated the effects of spatial scale on the distribution patterns of taxonomic, phylogenetic, and functional diversity indices. We also tested how relationships between taxonomic, phylogenetic, and functional diversity and various environmental and anthropogenic variables change across spatial scales. The results showed that with increasing spatial scale, species richness and phylogenetic and functional richness consistently increased. Community-wide mean pairwise distance indices for phylogenetic and functional dimensions also increased, while fine-scale mean nearest taxon distance indices decreased. Notably, community structure indices exhibited nonmonotonic patterns across spatial scales. The associations between diversity patterns and environmental and human covariates increased with scale but were more variable and complex across regions. These findings highlight a negative correlation between spatial scale and phylogenetic and functional divergence while reinforcing the species-area hypotheses for richness-dependent diversity indices. Identifying the optimal scales of field studies and conservational actions must factor in the species group of interest and the geographical context.