INVESTIGADORES
BORTOLUS alejandro
artículos
Título:
Spatial variation in molluscan assemblages from coralline turfs of Argentinean Patagonia.
Autor/es:
BP KELAHER,; JC CASTILLA,; L PRADO,; P YORK,; E SCHWINDT,; ALEJANDRO BORTOLUS
Revista:
JOURNAL OF MOLLUSCAN STUDIES
Editorial:
Oxford University Press
Referencias:
Año: 2007 vol. 73 p. 139 - 146
ISSN:
0260-1230
Resumen:
Abstract Patterns of spatial variation of molluscan communities associated with coralline algal turf were evaluated over 1000 km of the coast of Argentinean Patagonia. A hierarchically-nested experimental design was used to determine the relative importance of molluscan assemblage variation at three different spatial scales (shores, sites and cores). Hypotheses were also tested about the potential role of habitat variables (frond density, frond length, sediment and epiphytes) for determining molluscan community structure. In total, 37 molluscan species were found comprising 4, 16 and 17 species of polyplacophorans, gastopods and bivalves respectively. Densities of molluscs in coralline turf reached ca. 77000 individuals per m2 and were dominated by mussels, especially Perumytilus purpuratus. Multivariate and univariate analyses of assemblage structure consistently showed that variation at the scales of metres dominated and at the scales of 100s of km, with sites 20-50 m apart always between 0-23% of the total. Significant associations between molluscan community structure and both frond density and frond length demonstrated the potential importance of habitat structure in determining community structure at local scales. Variation in molluscan assemblages at the scale of shores, however, did not appear to correlate with latitudinal, temperature or wave exposure gradients, indicating other processes must be operating. The compositions of molluscan assemblages in coralline turf on the coast of Argentina were similar to those reported for central Chile. Comparisons of the richness of these South American assemblages to other parts of the world revealed some striking biogeographical patterns that warrant further investigation. Overall, this work highlights the general importance of small-scale variation in molluscan assemblages on rocky shores and the consistent influence of habitat complexity for determining the structure of diverse molluscan communities associated with mat-like habitats.