Revista Chilena de Historia Natural 84 (1): 143-154, 2011
RESEARCH ARTICLE
Geographic variation in diversity of wave exposed rocky intertidal communities
along central Chile
Along the coast of central Chile, geographic trends of diversity have been
inferred from literature compilations and museum collections based on species range limits for some taxonomic groups.
However, spatially-intensive fieldbased assessments of macrobenthic species richness are largely missing. Over the course
of a multiyear study (1998-2005), we characterized latitudinal patterns of rocky intertidal diversity at 18 sites along the coast
of central Chile (29-36º S). At each site, the number of sessile and mobile macrobenthic species was quantified in 0.25 m2
quadrats. Two estimators of local (alpha) diversity were used: observed local species richness, calculated from the
asymptote of a species-rarefaction curve, and the Chao2 index, which takes into account the effect of rare species on
estimates of local richness. We identified a total of 71 species belonging to 66 genera for a total of 86 taxa. The most
diverse groups were herbivorous mollusks (27 taxa) and macroalgae (43 taxa). Diversity showed a complex spatial pattern
with areas of high species richness interspersed with areas of low richness. In accordance with previous work, we found no
trend in the number of herbivorous mollusks and an inverse and significant latitudinal gradient in the number of algal
species. Our results highlight the need for taxonomically diverse assessments of biodiversity of the dominant taxa that
conform intertidal communities.
Key words:
biological
diversity, intertidal ecology, latitudinal diversity gradient, species richness
