Experimental estimates to measure changes in ocean ecosystems from 1988 to 2021.
Towards A National Ocean Account is a discussion article that highlights what was learnt through the development of the National Ocean Account with a view to the near future. The article is also a call for comments on the functionality and use of the accounts in this format.
In 2021, total mangroves increased 2.3% (23.5 thousand hectares).
Mangroves were:
166 thousand hectares of mangroves showed increased canopy cover from 2020.
60.2 thousand hectares of mangroves showed decreased canopy cover from 2020.
850.1 thousand hectares of mangroves showed no change in canopy cover.
Mangrove ecosystems were predominantly located in:
The national increase was driven by increases in:
As at 30 June 2021, the total extent of known seagrass meadows was between 2.56 million and 3.06 million hectares. Lower and Upper extent estimates are only available for the Gulf of Carpentaria, the Torres Strait, and the Great Barrier Reef World Heritage Area.
Approximately one third (32%) of seagrass is located outside state boundaries in other commonwealth waters, mainly in the Torres Strait.
Around 20% of seagrass is found in each of Western Australia, South Australia, and Queensland.
At the sediment compartment level, the largest contributors to seagrass extent were:
Estimates of seagrass density and persistence are available for the Gulf of Carpentaria, Torres Strait, and Great Barrier Reef. Over these areas:
As at 30 June 2021, 243 million tonnes of carbon were stored in mangrove ecosystems.
Between 289 and 341 million tonnes of carbon were stored in known seagrass meadows.
Mangrove carbon sequestration services were 8.6 Mt CO2e per annum in 2021 (or the equivalent to emissions of 2.8 million cars), flat on 2016 (0.6% increase).
National carbon sequestration estimates for seagrass as at June 30 2021 range between 4.9 and 5.6 Mt CO2e (or the equivalent to emissions of 1.6 to 1.9 million cars).
In 2021, 85.6 thousand dwellings received coastal protection services from Mangroves. The majority of dwellings (52 thousand) were in Queensland.
175 thousand people received coastal protection services from Mangroves. The majority of people (107 thousand) were in Queensland
18.8 thousand kilometres of Australia's coastline was offered coastal protection by mangroves. The states with the longest length of coastline protected were:
The replacement cost of mangroves offering coastal protection services is $218.7 billion dollars in seawall construction. The states with highest replacement costs were:
$2.2 billion in minimum annual services value and $8.7 billion in maximum annual services value as the economic replacement cost offered by mangroves.
19/12/2022 – Closing Stock of Seagrass Persistence (Primary sediment compartments) updated to reflect persistence data