Abundance-Occupancy Relationships in Deep Sea Wood Fall Communities

The generally positive relationship between the number of sites a species occupies and its average abundance within those sites provides an important link between population processes occurring at different spatial scales. Although such Abundance-Occupancy Relationships (AORs) have been documented across a very wide range of taxa and in many different environments, little is known of such patterns in Earth's largest ecosystem, the deep sea. Wood falls—derived from natural or anthropogenic inputs of wood into the oceans—constitute an important deep-sea habitat, habouring their own unique communities ultimately entirely dependent on the wood for chemical energy. In this study we take advantage of the unique features of an experimental wood fall deployment to examine AORs for the first time in deep-sea invertebrates. The study design combines advantages of both experimental (tractability, control of key environmental parameters) and observational (natural colonisation by taxonomically diverse communities) studies. We show that the interspecific AOR is strongly positive across the 48 species occurring over 32 wood fall communities. The precise form of the AOR is mediated by both species-level life history (body size) and by the colonisation stage at which communities were harvested, but not by environmental energy (wood fall size). Temporal dynamics within species are also generally consistent with positive intraspecific AORs. This support for positive AORs in the deep sea is an important extension of a macroecological generality into a new environment offering considerable potential for further testing and developing mechanistic macroecological theories.