This study aimed to identify factors responsible for the persistence of barrens created by H. erythrogramma in Tasmania, by assessing whether recovery of native canopy-forming algae on sea urchin barrens can be inhibited in the absence of intense sea urchin grazing.
Site Selection Criteria:
The experiment was conducted at 7–10 m depth on rocky reef at Lords Bluff, situated at the northern extremity of the Mercury Passage on the east coast of Tasmania. At this site, a large Heliocidaris erythrogramma barren was found adjacent to reef dominated by a diverse assemblage of native canopy-forming species including the common kelp Ecklonia radiata and the fucoids Phyllospora comosa, Carpoglossum confluens and Seirococcus axillaris.
Cause Of Decline:
C. amentacea var. stricta and C. compressa form complex communities providing habitats for numerous epiphytic species and shelter for many shade-loving organisms. For decades, the Region Provence-Alpes-Cote d’Azur’s coastline (France) has been exposed to water pollution and many studies have reported severe degradations or even disappearance of Cystoseira popula. Despite the setting up of a wastewater treatment plant in the vicinity of the Marseille sewage outfall 8 years ago, C. amentacea var. stricta has still not recolonised its former habitat.
Persistence of sea urchin (Heliocidaris erythrogramma) barrens on the east coast of Tasmania: inhibition of macroalgal recovery in the absence of high densities of sea urchins
Botanica Marina, Vol. 48.https://doi.org/10.1515/bot.2005.025