The aim of this paper was to critically test the effect of H. erythrogramma on macroalgal habitat when the sea urchin occurs at relatively low but typically observable densities of 46 individuals per square meter.
Site Selection Criteria:
Experimental plots were established on sheltered reefs (2–10 m depth). Typical of sheltered coastal reefs in eastern Tasmania, these locations contained moderate densities of H. erythrogramma, and were associated with macroalgal impoverished rocky reef habitat, i.e. ostensibly sea urchin barrens habitat.
Cause Of Decline:
In temperate Australia, the sea urchin Heliocidaris erythrogramma is considered an ecologically important herbivore on shallow sub-tidal reef assemblages. However, there is a paucity of evidence demonstrating the capability of this species to graze and modify benthic habitats. Over much of its range H. erythrogramma is observed in association with macroalgal dominated rocky reefs where the sea urchin appears to have little or no influence on standing macroalgal communities. Nonetheless, in some parts of its range, and frequently observed on sheltered Tasmanian reefs, H. erythrogramma can be found in association with macroalgal impoverished rocky reefs ostensibly caused by the sea urchin consuming canopy-forming brown algae.
, Vol. 395., Journal of Experimental Marine Biology and Ecologyhttps://doi.org/10.1016/j.jembe.2010.08.027