Regional ecosystems
Regional ecosystems are vegetation communities that consistently occur on particular soil types, geology and landforms in an area. This broad classification system can be used to predict the vegetation that would have occurred in an area. In Seaforth, we are part of the Central Queensland Coast Bioregion. Landforms include basalt plains and hills, coastal dunes and river and creek flats. This gives important information about the soil type, geology and environmental conditions in an area.
Dune vegetation zonation along the length of Seaforth Beach is highly variable, and there are localised areas
which retain natural dune zonation including colonising spinifex and casuarina woodland on foredunes, and
open forest communities beyond the frontal dune. There are also pockets of eucalypt and acacia open forest with beach scrub understory.
Mangroves
Mangroves are trees, shrubs, palms or ground ferns, generally larger than half a metre in height, that grows above mean sea level in the intertidal zone of marine coastal environments and estuarine margins. The term mangrove also refers to the tidal habitat in which these plants grow.
The intertidal zone is a harsh environment and mangrove species are adapted to tolerate these conditions. Mangrove soils are regularly water-logged ad loaded with salt. High tides bring saltwater inundation, while low tides expose mud and roots to heat and desiccation. Some plants have above ground breathing roots to cope with growing in water saturated conditions. Mangroves also have specialised attributes for growing in salty environments with saturated airless soils. The seeds of some mangrove species germinate on the parent plant and the new seedling remains attached as it grows. Propagules such as fruits and seeds can often survive at sea for many months, before they wash up in a suitable area for them to grow.
Some of the mangrove species found include;
- Grey Mangrove – Avicennia marina var. eucalyptifolia
- Large-leafed Orange Mangrove – Bruguiera gymnorhiza
- Smooth-fruited Yellow Mangrove – Ceriops australis
- Milky Mangrove – Excoecaria agallocha
- Keeled-pod Mangrove – Heritiera littoralis
- White-flowered Black Mangrove –Lumnitzera racemosa
- Long-style Stilt Mangrove – Rhizophora stylosa
- White-flowered Apple Mangrove – Sonneratia alba
An estimated 75 percent of fish caught commercially spend some time in mangroves or are dependent on food chains which can be traced back to mangrove environments. Mangroves also protect the coast by absorbing wave and wind energy, particularly during storms. Mangrove roots can trap sediments and help protect corals and sea grasses in adjacent marine habitats, which can be killed by high levels of sedimentation.