Meeting Abstract

35.5  Monday, Jan. 5  The presence of community structure varies with spatial scale in Lake Malawi cichlid fishes. PARNELL, N.F.*; STREELMAN, J.T.; Georgia Institute of Technology; Georgia Institute of Technology gth877n@mail.gatech.edu

A long-standing issue in ecology is the existence and related causes of structure in natural communities. Here, we use null model simulations of species co-occurrence to examine the spatial structure of the cichlid fish assemblage in Lake Malawi, Africa. We employed the C-score model to test the null hypothesis of random structure at increasingly fine spatial scales (lakewide to depth-within-site). Communities were not different from the null model until examined at the finest grain (depth-within-site), at which point we detected a strong and significant signal of structure. To further investigate the intricacies of cichlid community structure at depths within sites, we focused more closely on the identity of species and their trophic habits across replicated local assemblages (rock reefs separated by dispersal boundaries). We identified complex species combinations with putatively positive and negative interactions among them. Our analysis provides insight into how communities may be structured in highly diverse, dispersal-limited vertebrates.