Mangrove distribution in Northwestern Australia in relationship to regional and local freshwater seepage
- Cite this article as:
- Semeniuk, V. Vegetatio (1983) 53: 11. doi:10.1007/BF00039767
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The regional distribution of mangrove species along the tropical NW coast of Australia is closely related to climate. In subhumid regions with rainfall >1000 mm/yr mangals have 12 species which are recurring and common. The climate becomes more arid southwards and species richness decreases: 8 species are common in mangals in semiarid regions and 5 species are common in arid regions. Rainfall influences the distribution of species across tidal flats because of direct recharge to groundwater systems and also because of subsurface seepage along the hinterland edge. Much of the increase in species diversity is located along high parts of tidal flats and along the edge of the hinterland.
At the local level stratigraphy forms an important part of the hydrology by determining the distribution of aquifers and aquacludes. Fresh water seeps into the tidal lands via buried, discrete aquifers and dilutes the highly hypersaline groundwater. Mangroves inhabit these local areas above the less saline groundwater. The influence of rainfall and freshwater seepage on mangals is presented as a unifying theme which helps to explain distribution and diversity of mangroves at both a regional and local level.