Changing coastal landscapes: Where are mangroves going?

Mangroves and saltmarsh are vital to many valuable ecosystem services, such as their capacity to sequester carbon dioxide and mitigate climate change effects. Whilst, the organic carbon sequestered within these ecosystems is... [ view full abstract ]

Mangroves and saltmarsh are vital to many valuable ecosystem services, such as their capacity to sequester carbon dioxide and mitigate climate change effects. Whilst, the organic carbon sequestered within these ecosystems is comparable to terrestrial forests, they have been subjected to large global declines and degradation, which in turn can contribute to increasing CO2 emissions due to the loss, and subsequent erosion or conversion of carbon soil deposits. In fact, across Australia 50% of mangroves and saltmarsh have been lost or significantly degraded. With 80% of the population residing in the coastal zone, much of this can be contributed to anthropogenic change.

This study utilised remote sensing to quantify the areal change of mangroves and saltmarsh over a 23 year period across land use categories at various sites within Australia that encompass low to high anthropogenic influences. In doing so, this study was able to illustrate the changing estuarine environment and determine the land use categories that are expanding onto former mangrove and saltmarsh areas, thereby helping elucidate the drivers of their decline. Whilst many studies have mapped mangroves and vegetation at sites across Australia, this study is able to provide key data in analysing the change between land use categories temporally. This is vital for their continued conservation amid a growing population and climate change scenarios that are predicted to largely impact this zone. Further this study discusses the change in mangrove and saltmarsh area in relation to the drivers of change (e.g., anthropogenic, climatic) which will enable the behaviour of mangroves to ascertained pressures (e.g., post reclamation recovery, tidal restrictions, conversion to parkland) to be employed to determine the historic and future influence on the ecosystem services they provide.