|Benthic biodiversity is used as a proxy for ecosystem health of the Great Australian Bight Marine Park (Commonwealth Waters) (GABMP CW). The Benthic Protection Zone (BPZ) of the GABMP (CW) was proclaimed in 1998 to preserve a representative sample of the benthic flora and fauna and sediments (Director of National Parks 1999; Director of National Parks 2005). The BPZ is a 20 nautical mile wide strip orientated north to south and extends 3 nautical miles from the coast to the edge of Australia's Exclusive Economic Zone (200 nautical miles offshore). Within the zone, benthic assemblages are protected from demersal trawling and other potentially destructive human activities. There was a lack of information on the benthic communities of the GAB region at the time of the establishment of the GABMP (CW) and the location of the BPZ was not based on quantitative ecological data.
|Natural Resource System
|Marine protected areas
|Somewhat unclear boundaries (2)
|The boundaries that define the spatial extent of this commons are biophysical and do not reflect the boundaries of the GABMP (CW). Species richness and biomass generally declines with increasing depth and distance offshore and benthic community composition was found to reflect the spatial distribution of the sedimentary facies on the shelf (Ward et al. 2003). In the deep-water survey, the infaunal communities of the BPZ slope were found to be more diverse than those found on the shallower waters of the adjacent continental shelf although, infaunal abundance declined with increasing depth (Currie and Sorokin 2011).
Benthic communities have been found to be significantly different inside and adjacent to the Benthic Protection Zone (BPZ) of the GABMP (CW) (Ward et al. 2003; Currie et al. 2008)
|The shelf bedforms of the GAB are largely biogenic and form a large expanse of temperate carbonate sediments. The sediments are generally coarse-grained and gravelly inshore but become progressively finer and muddier with increasing depth and distance offshore (Connolly and Von Der Borch 1967).
|Inter Annual Predictability
|The marine ecosystems of the GAB have received less research attention than other areas of temperate Australia because of its remote location. Species composition of the benthic communities in the GABMP were unknown prior to Park implementation.There is little information on the benthic communities or environmental factors that affect their patterns of distribution or abundance. The first quantitative epibenthic survey of the region was undertaken in 2002 and was aimed at assessing the effectiveness of the GAB BPZ in representing regional biodiversity (Ward et al. 2003, 2006). The 2002 sites were re-surveyed in 2006 and the patchy distributions in the populations of species suggested that a high proportion of the benthic fauna residing in and around the BPZ has not yet been sampled. A preliminary assessment of the deepwater benthic communities of the GABMP beyond the shelf-break was conducted in 2011 (Currie and Sorokin, 2011).
|Intra Annual Predictability
|Poriferans, ascidians and bryozoans dominated the biomass of benthic species found in the GABMP and these marine invertebrates are renewable.
|Very productive (3)
|The life-cycle of poriferans, ascidians and bryozoans, which dominate the biomass of benthic species found in the GABMP, can incorporate phases of both asexual and sexual reproduction. A survey in 2002 established that the macrofaunal communities of the eastern GAB shelf are among the worlds most diverse (with almost 800 invertebrate species being identified from 65 sled tows of 5-minute duration) (Ward et al. 2003). A species accumulation model developed with contemporary grab data suggests that the deep-water infaunal communities of the BPZ slope are more diverse than those found on the shallower waters of the adjacent continental shelf although, infaunal abundance declined with increasing depth (Currie and Sorokin 2011).
|Somewhat accessible (2)
|The benthic communities of the GABMP (CW) are accessible with the use of technology (large boats that have equipment with appropriate substrate sampling equipment such as a benthic sled or an underwater video system).
|Similar benthic assemblages are found inside and outside of the BPZ of the GABMP (CW) although a marked shift in species representation was observed between the two surveys (2002, 2006). However, populations of individual species had patchy distributions suggesting that a high proportion of the fauna in and around the BPZ of the GABMP (CW) has not yet been sampled (Ward et al. 2003; Currie et al. 2008)
|Commons Spatial Extent
|This is the approximate spatial extent of the GABMP (Commonwealth Waters) that this environmental commons is found in similar benthic communities are found throughout the GAB region.