Recovery of benthic communities following the installation of Environmentally Friendly Moorings

Scouring form moorings can cause large-scale seagrass loss and changes in the benthic community. As a result, there has been a push to design moorings that will minimize impact to the benthic community. In Moreton Bay the... [ view full abstract ]

Scouring form moorings can cause large-scale seagrass loss and changes in the benthic community. As a result, there has been a push to design moorings that will minimize impact to the benthic community. In Moreton Bay the Environmentally Friendly Mooring Program (EFM) began in 2009. The objective of the program was to replace traditional block and chain moorings with EFMs to minimize the damage to marine habitats and promote the recovery of marine habitats in areas once damaged by scouring from traditional block and chain moorings. The objectives of this study were to quantify the recovery of the benthic community following the installation of EFMs. We found that EFMs had an average scour of 1.1m (±0.2) diameter; an area significantly smaller than the estimated average EFM recovery area of 19.2m (± 2.5) diameter. There was overall good recovery of vegetation within 1-2 years of EFM installation, averaging 40-60% vegetated cover. However, the species that did colonize the EFM recovery sites tended to be the faster growing pioneering species, with just two species dominating each study site. Fast growing species recovered to shoot densities and biomasses similar to positive control sites; whereas the slower growing species, Zostera muelleri and Cymodocea serrulata, had significantly lower biomass and shoot density than positive control sites. Overall, the installation has promoted seagrass and macroalgal recovery in Moreton Bay. However, the recovery is dominated by pioneering species that are unlikely to have the same ecosystem services as well larger, slower going climax species. Therefore, it may be several years until the recovery sites reach their full functional recovery.