Abundance-Body Size Relationships: The Area You Census Tells You More

Abstract

The interspecific relationship between abundance and body size in animals is often claimed to be strongly negative, with species abundance limited by energetic requirements. This view has been criticized for a number of reasons, but is still widely accepted. Here, we provide evidence of further fundamental difficulties with this relationship as derived from compendium studies. We suggest that there is a potential artefactual component to these relationships resulting from variation in the areas over which the densities of species of different body size are censused, and differences in the ways species use these areas. While the interspecific relationship between body size and abundance is still likely to be negative after accounting for the artefactual component, the slope of the relationship is unlikely to support energetic equivalence arguments.