MEPS 588:15-27 (2018)  -  DOI: https://doi.org/10.3354/meps12404

ABSTRACT: High variability in species diversity among samples from the same site is a consistent pattern described for several benthic marine assemblages. In general, small-scale spatial variability has been shown to be as significant as regional-scale variability in species diversity, indicating that the processes which generate such patterns are equally important in both cases. However, the focus of most ecological studies is to understand species diversity at a regional scale. Using epibenthic assemblages associated with mangrove roots, we experimentally evaluated the effects of colonization timing, succession and species-area relationships as factors that might explain the high occurrence of small-scale variability observed in nature. Assemblages were evaluated on artificial mangrove roots deployed at different sites and times, and under different environmental conditions, along 500 km of the Southern Caribbean coast. Residual variation obtained in this experiment was compared with variation among natural neighboring roots in order to test the hypothesis that the former would be lower. The identities and abundances of both colonizing and late-successional species varied considerably among sites and colonization timing; nevertheless, changes in assemblage structure always occurred in the same direction. No relationship among richness and structure of assemblages was associated with root area. Residual variation was considerably lower (40%) than variation measured in natural neighboring roots, indicating that colonization and succession explained a significant component of the variation in assemblages among neighboring roots. Understanding the mechanics of these processes could be the key to understanding small-scale spatial variability of benthic assemblages.

KEY WORDS: Supply-side ecology · Benthic assemblages · Colonization · Succession · Rhizophora mangrove roots