Latitudinal patterns of species diversity on South American rocky shores: Local processes lead to contrasting trends in regional and local species diversity

JUAN JOSE CRUZ MOTTA; PATRICIA MILOSLAVICH; EDLIN GUERRA-CASTRO; ALEJANDRA HERNANDEZ; CESAR HERRERA; FRANCISCO BARROS; M. G. PALOMO

JOURNAL OF BIOGEOGRAPHY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020 vol. 47 p. 1966 - 1979

0305-0270

AbstractAim: We evaluated whether patterns of species diversity (α, β and γ) of rocky shoreassemblages followed latitudinal gradients (i.e. LDGs) along the South Americancoasts, and tested hypotheses related to potential processes sustaining or disruptingthe expected LDG pattern at various spatial scales.Location: Coasts of South America.Taxon: Macroalgae and sessile/slow-moving macrofauna on intertidal rocky shores.Methods: We evaluated changes in species composition across 143 sites. The degree of replacement and loss of species at different spatial scales (i.e. coasts, regionsand sites) were estimated to help distinguish among ecological, historical and evolutionary hypotheses for explaining LDGs. Furthermore, components of diversity andtaxonomic distinctness were measured, and variability in these measures was decomposed using analysis of covariance. Finally, we examined relationships between diversity and a suite of environmental and anthropogenic variables to identify potentialmechanisms that may be responsible for the reported spatial relationships.Results: Species composition varied with latitude, and this variability was relativelyconsistent on both coasts. At all spatial scales, replacement of species was the dominant phenomenon (>95%), rather than loss in the total number of species (