The distribution and dynamics of mangroves are influenced by a number of factors relating to the terrestrial environment, with these including hydrology and geomorphology
Hydrology The discharge or water and sediment through rivers has an impact on mangroves, leading to erosion on the coastline but also accretion with this often leading to loss and gains of mangroves and changes in structure. An example is provided for the Gulf of Carpentaria, which shows extensive flooding in the Flinders River and proximal catchments (Asbridge et al.., 2016)
Geomorphology Along the coastline of Australia, a wide range of coastal landform (or geomorphological) types have been recognized and described on the basis of topography, elevation, shape and composition (e.g., based on rock types, unconsolidated materials. These include coastal plains (e.g., along the Gulf of Carpentaria) but also more topographically diverse areas (e.g., the Kimberley). Tidal ranges are high in the north of Australia, in particular, and the extent of inundation at the higher tidal levels is greatest in low lying and flat terrain. Many mangrove areas are sheltered from high energy waves, including along the north-east tropical coastline (as these are moderated by the Great Barrier Reef), the northern coast (because of reduced exposure to large oceanic pressure systems and fetches) and southeastern Queensland (because of an extensive chain of sand islands). Along the coast of New South Wales, ocean waves impact the exposed portions of the coastline and hence mangroves are generally smaller in extent, dispersed and confined to sheltered embayments and estuaries. The varying lithologies also influence mangrove distributions as these determine (in part) the delivery of different sediment types and amounts to the coastal margin.
Where available, links to environmental conditions on the land surface that impact on the state and dynamics of mangroves are listed below.
- Land surface temperature
- Water inundation (frequency and period)
- Geomorphic setting
- Non-mangrove vegetation distributions.
References Asbridge, E., Lucas, R.M., Ticehurst, C. and Bunting, P. (2016). Mangrove response to environmental change in Australia's Gulf of Carpentaria. Ecology and Evolution, 6, 3523–3539, doi:10.1002/ece3.2140 (2016).