Researchers conducted an experimental manipulation to test whether the effects of grazing by Centrostephanus rodgersii were linearly related to density.
Site Selection Criteria:
Treatments were replicated in 4 discrete patches of barrens habitat, each between 3 and 4m2 in area. The crevices within these patches were comprised of either undercut platforms or boulders resting on the substratum. Patches used in the experiment were in water 2 to 5m deep, separated by at least 5m and spread over an area of approximately 2000m2.
Cause Of Decline:
The long-spined sea urchin Centrostephanus rodgersii is one of the most important grazers on rocky reefs in NSW. Grazing by C. rodgersii can remove foliose algae from large areas of reefs, while removing urchins leads to an increase in foliose algae and decrease in limpets and crustose coralline algae.
DENSITY-DEPENDENT FORAGING IN THE SEA-URCHIN CENTROSTEPHANUS-RODGERSII ON SHALLOW SUBTIDAL REEFS IN NEW-SOUTH-WALES, AUSTRALIA
Marine Ecology Progress Series, Vol. 99.https://doi.org/10.3354/meps099089