The aim of this study was to examine the impact of the range-extending sea urchin Centrostephanus rodgersii on reef habitat structure and associated biodiversity within their extended range in Tasmania by using controlled sea urchin removals.
Site Selection Criteria:
This study targeted sites that once had kelp but had been converted to urchin barrens.
Cause Of Decline:
Driven by increased poleward penetration of the warm East Australian Current (EAC), the sea urchin Centrostephanus rodgersii (Diadematidae) has recently undergone a southern range extension in temperate south-eastern Australia. These urchins are able to eliminate macroalgal habitat and effect a catastrophic shift to an alternative sea urchin ‘barrens’ state. Thus, C. rodgersii grazing in eastern Tasmania is considered to pose a major threat to the structure and functioning of the biologically diverse macroalgal-dominated rocky reefs.
Key Reasons For Decline:
Range expansion of a habitat-modifying species leads to loss of taxonomic diversity: a new and impoverished reef state
Oecologia, Vol. 156.https://doi.org/10.1007/s00442-008-1043-9