February 2nd is World Wetlands Day, celebrating the signing of the International Convention on the protection of Wetlands, commonly known as the Ramsar Convention. Moreton Bay is home to extensive Ramsar listed wetlands, recognised for their international significance.
Wetlands are among the most productive ecosystems in the world supporting a diversity of plants and animals, improving water quality, and providing coastal protection against destructive impacts.
Distribution of saltmarsh, mangrove, mudflat, seagrass and coral reef areas of the Moreton Bay wetlands were examined and reported in our publication: Moreton Bay Quandmooka and Catchments – past present and future: Ch4 Wetland and benthic cover changes in Moreton Bay
Figure 1 Moreton Bay Wetland environments, a transition zone between the land and the ocean. These arease undergo periodic inundation and include all environments to a depth of 6 m. The intertidal zone is the most landware zone of the wetlands and is exposed to the air at low tide, and submerged at high tide. The mid-intertidal zone indicated by the mean tide level (MTL) is regularly exposed and submerged. The intertidal zone encompasses saltmarsh, mangrove, seagrass and mudflat habitats. Wetland environments alsi include the inshore reefs found in shallow waters, atop a muddy substrate.
Anthropogenic activity has resulted in marked decreases in the areal extent of all Moreton Bay wetland communities, and remain their greatest threat:
Since 1955- well over 50% of Saltmarsh communities have been lost and Moreton Bay saltmarsh communities were listed as a vulnerable ecological community under the Commonwealth EBPC Act.
Of the original 1955 mangrove distribution 77% remained stable (9). Encouragingly, the rate of mangrove die-back attributed to human causes decreased by 84%, strongly correlated to listing as Ramsar wetlands in 1993.
Mudflat extent has increased than 50% in the past 30 years, largely attributed to recent floods, with mudflats now covering 860 km2 of the Bay.
Despite losses in the past Seagrasses persist in Moreton Bay across a wide range of environmental conditions from muddy sediments in the western Bay to the cleaner, sandier waters of the eastern Bay adjacent to Moreton (Moorgumpin) and Stradbroke (Minjerribah) Islands. There has been an encouraging recovery of meadows in some of the more degraded parts parts of the Bay as a result of management efforts.
Continued monitoring, management and protection of the Bay’s wetland communities through government, scientific and community organisations is vital in ensuring these ecologically, socially and economically important wetland habitats thrive into the future.
