Western Indian Ocean coral and fish normalized site richness collected between 1991 to 2000

Aim: Strong social-ecological trade-offs between resource extraction and
protection have created challenges for large, protected area management in
natural-resource-dependent countries. Therefore, local governments and
community conservation activities are becoming common and need information
about low environmental exposure and high biodiversity for planning
localized conservation activities. Location: the western Indian Ocean
Methods: Coral reef sites were evaluated for local scale environmental and
species richness to elucidate local patterns in spatial heterogeneity.
Local coral and fish taxonomic richness were normalized to partially
account for common and heterogeneous disturbances to coral cover and fish
biomass. Residuals were evaluated for patterns of local diversity with
geography, environmental stress, and by machine learning to evaluate the
relationship with 21 specific environmental variables. Results: High
variability in richness was found at similar latitudes where richness was
high. Relationships with specific environmental and human influences
variables were complex and spatially heterogeneous. Expected large-scale
biogeographic variables influenced richness but variability and
environmental influences were highly specific and localized. Among the
environmental and human influence variables examined, ~ 8 variables
contributed 8 to 25% of the variance to the richness of both coral and
fishes. Main conclusions: Decisions to focus small-scale conservation on
locally biodiverse locations could contribute to species persistence by
planning for local heterogeneity in richness and stress. From this
specific data set, sites in the Pemba Channel between the Tanzanian
mainland and Pemba Island, and northern Mozambique and Madagascar fit
these characteristics.