The keystone species concept originated from studies on the funcional role of the predator starfish Pisaster ochraceus. This species enhances biodiversity by preventing space monopolisation by potentially dominant species. An opposite role may be played by echinoderm grazers such as sea urchins which depress species richness and diversity values of benthic communities. In the Mediterranean Sea endolithic date mussels are collected by rock dismantling this causing disruption of hard bottom communities and desertification of large areas. At these sites, grazing activity of large populations of sea urchins heavily impairs recolonisation. Furthermore, we hypothesize that high densities of Paracentrotus lividus and Arbacia lixula might be related to the absence of common predators such as the starfish Marthasterias glacialis.
Opposite roles of sea urchins and starfishes in marine benthic communities
PIRAINO, Stefano;
1999-01-01
Abstract
The keystone species concept originated from studies on the funcional role of the predator starfish Pisaster ochraceus. This species enhances biodiversity by preventing space monopolisation by potentially dominant species. An opposite role may be played by echinoderm grazers such as sea urchins which depress species richness and diversity values of benthic communities. In the Mediterranean Sea endolithic date mussels are collected by rock dismantling this causing disruption of hard bottom communities and desertification of large areas. At these sites, grazing activity of large populations of sea urchins heavily impairs recolonisation. Furthermore, we hypothesize that high densities of Paracentrotus lividus and Arbacia lixula might be related to the absence of common predators such as the starfish Marthasterias glacialis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
