IUCN Red List of Ecosystems, Mangroves of the Australian Coral Sea

Tertius de Kluyver, Norman C. Duke, Catherine E. Lovelock, Ena Suarez, Sean G. MCGregor

Mangroves of the Australian Coral Sea is a regional ecosystem subgroup (level 4 unit of the IUCN Global Ecosystem Typology). It includes the marine ecoregions of the Central and Southern Great Barrier Reef, Coral Sea, Torres Strait Northern Great Barrier Reef, and Tweed-Moreton. The Australian Coral Sea mangrove province mapped extent in 2020 was 2398.3 km2 across, representing 1.6% of the global mangrove area. The biota is characterised by 46 species of mangroves.
This bioregion is notable for having the most biomass-rich mangrove forests in Australia, with trees reaching heights of 25–30 meters, particularly in lush tropical areas adjacent to the Wet Tropics rainforests, such as the Daintree River. Isolated pockets along the northeast coast also exhibit both high biomass and biodiversity. The mangroves are divided into three sub-regions, based on rainfall, tidal ranges, and distinct geological and physiographic conditions.
Today the Australian Coral Sea mangroves cover ≈8% more than our broad estimation for 1970, although the mangrove net area change has been -1.6% between 1996 and 2020. If this trend continues an overall change of -5.3% is projected over the next 50 years. However, an alternative scenario, based on mangrove forest dynamics, suggests that cyclical increases and decreases may result in relatively stable mangrove cover over time. Furthermore, under a high sea level rise scenario (IPCC RCP8.5) ≈-7.2% of the Australian Coral Sea mangroves could be submerged by 2060. Additionally, 1.1% of the province’s mangrove ecosystem is undergoing degradation, with the potential to increase to 3.4% within 50 years, based on a vegetation index decay analysis. Overall, the Australian Coral Sea mangrove ecosystem is assessed as Least Concern (LC).