Mesoscale β diversity and spatial nestedness of crustacean larvae in the coastal zone off central southern Chile: population and community implications

Spatial connectivity among populations is one of the central themes in marine ecology. This study evaluates the presence of mesoscale spatial patterns in meroplanktonic stages of decapods and stomatopods. The hypothesis is that beta diversity increases with geographic distance at a mesoscale level. Seven oceanographic cruises were conducted in central southern Chile between May 2006 and February 2008. Samples were collected using a bongo net (300 mm) towed through the top 15 m of the water column. To test the hypothesis, (i) the beta diversity of early stages of decapods and stomatopods was quantified, (ii) a linear model was fitted between b diversity and the geographic distance among all possible pairs of sampling sites, and (iii) a nestedness analysis of species richness was performed to evaluate the effect of local transport on species diversity. There was a positive relationship between b diversity and geographic distance, and a nestedness pattern in most sampling periods, suggesting that a source-sink dynamic dominates between nearby sites and that larval dispersion is limited, inducing low levels of population connectivity.