Mangroves and associated communities of Moreton Bay

Intertidal ecosystems, including mangrove and saltmarsh communities, provide significant social, cultural, economic and ecological values. In recognition of these values, the monitoring, assessment and reporting of these ecosystems has been a central focus of resource managers and stakeholder groups.

Mangrove and associated communities are essential for maintaining the health of fisheries and coastal and marine seascapes and ecosystems. While these communities are currently protected under the Fisheries Act (1994), they are vulnerable to impacts from coastal development as well as from changes to natural processes such as siltation, nutrient runoff and climate.

The report Mangrove and associated communities of Moreton Bay, Queensland, Australia: change in extent 1955-1997-2012 (2016) by the Queensland Herbarium documents the change in extent of each mangrove and associated community from 1955 (historical) to 2012 for Moreton Bay. Supported by the earlier 1974 mapping and the 1997 mapping.

Mangrove communities have increased in area by 958 ha (6.7%) between 1955 and 2012 whereas saltmarsh communities (including samphire, marine couch and claypan) have lost 5,730 ha (64%) of their 1955 extent. Casuarina glauca communities have lost 732 ha (31%) of their area during the same period. The spatial extent of each mangrove and associated community are described for the period from 1955 to 2012. While these communities are all dynamic in nature, losses due to anthropogenic causes have also have occurred mainly from urban and infrastructure development.

Changes in extent of mangrove communities from 1955 to 2012

• 11,000 ha were stable
• 3,282 ha, either changed to another community type or lost due to anthropogenic causes
• 4,209 ha were gained by encroachment into other communities
• some mangrove communities types have increased in area where others have decreased
• there was a net overall gain of 927 ha of mangrove communities
• the net rate of mangrove encroachment into saltmarsh and Casuarina glauca communities was 50% lower in the 1997-2012 period in comparison to the 1955-1997 period.

Changes in extent of saltmarsh communities including samphire, marine couch and claypan from 1955 to 2012

• 2,400 ha were stable
• 6,410 ha either changed to another community type or were lost due to anthropogenic causes
• 710 ha were gained by encroachment into other communities;
• there was a large decrease across all the saltmarsh vegetation community types
• there was a 5,700 ha overall net loss of saltmarsh communities
• the net rate of saltmarsh community invasion by mangrove and Casuarina glauca communities was 43% lower in the 1997-2012 period in comparison to the 1955-1997 period. 

Changes in extent of Casuarina glauca communities from 1955 to 2012

• 759 ha were stable 
• 1,411 ha either changed to another community type or lost due to anthropogenic causes
• 687 ha were gained by encroachment into other communities
• some Casuarina glauca communities have decreased in area where others increased
• there was a 724 ha overall net loss in Casuarina glauca communities
• the net rate of Casuarina glauca communities encroachment into mangrove and saltmarsh communities was higher in the 1997-2012 period in comparison to the 1955-1997 period.

Additional information

• Moreton Bay Marine Park
• Mangrove Watch
• Queensland Museum Mangrove Challenge
• The Nature Conservancy Policy Brief: Securing The Future Of Mangroves

Last updated: 17 June 2016