Spatial diversity of nematode and copepod genera of the coral degradation zone along the Kenyan coast, including a test for the use of higher-taxon surrogacy

The biodiversity of meiofauna in the coral degradation zone along the Kenyan coast was examined with special emphasis on the most abundant taxa, Copepoda and Nematoda. Communities from three microhabitat types (coralline sediment, coral gravel and coral fragments) at two locations (Watamu and Tiwi Beach) were analysed. The total number of meiofaunal taxa was higher than in any other tropical coral degradation zone studied so far, but lower than in a cold-water coral degradation zone. Meiofaunal community composition was mainly structured on a local scale, although microhabitat type also had an effect in Watamu. Copepod and nematode communities exhibited comparable trends in biodiversity. The coralline sediment was generally characterised by a higher genus richness than the other microhabitats, and coral fragments were consistently low in evenness. Differential susceptibility to hydrodynamic disturbance is proposed as an explanation. Coral fragments contributed considerably to the total diversity in terms of the number of nematode and copepod genera. It is therefore recommended to include this microhabitat in future biodiversity studies on tropical lagoons. Trends in biodiversity were similar for genera and families. The use of family-level identifications in fast screening and comparison of biological diversity is endorsed by this study.