Wetlands are areas of land that are flooded naturally or are waterlogged on a seasonal or intermittent basis. They can be ponds, lakes, swamps, marshes or billabongs.
The Darling Basin has a variety of wetlands, many of which have special features of high ecological value. Many species of amphibians, fish, birds and animals are dependent on them for their survival. They also store carbon and nutrients which are recycled back into the rivers and streams, helping to keep them healthy.
Wetlands support a variety of unique vegetation types that must survive the wet and dry extremes of the Australian inland climate. Most of the wetlands in the region are ephemeral (that is, they dry out); the plants growing in them are well adapted to floods and long droughts.
There are three key wetland plant communities in the Upper Darling:
- Lignum communities are found on alluvial cracking clay soils that are subject to periodic flooding. The boundaries of Lignum communities are usually well defined, but they are occasionally associated with Coolabah or River Red Gum.
- Canegrass communities occur on low areas of sandy or compact light clay soils that are subject to inundation, usually in the West of the region. Canegrass forms large clumps that are evenly distributed through the wetland.
- Marsh (or swamp) communities have a higher requirement for water and are areas of more or less permanent, shallow, still or slow moving water. They are commonly associated with the lower reaches of the major rivers in the region. The dominant plants are numerous species of reeds or rushes. Some of these species are tall and form dense continuous stands.
Wetlands were originally thought to be of little value, but it is now known that they are very important for the overall condition of the catchments in which they occur.