The Wet Tropics World Heritage Area has a huge variety of aquatic ecosystems - fast moving streams flowing from mountaintops, rapid rivers cascading through gorges and over waterfalls, meandering coastal rivers and associated wetlands, mangrove communities and estuaries. The majority are freshwater ecosystems, but coastal mangrove communities and estuarine systems support both freshwater and saltwater ecosystems.
Small areas of the World Heritage Area may also include marine species in the mangrove and estuarine systems and marine mammals such as turtles nesting on the dunes above the beach. The Area's boundary goes to the low water mark. Some freshwater species such as barramundi and eels spend parts of their life cycle in the marine environment. These aquatic values are shared with the adjoining Great Barrier Reef World Heritage Area.
The bioregion is drained by 13 major river systems, most of which drain eastward into the Great Barrier Reef World Heritage Area and are linked to marine ecosystems there. There are 30 wetlands of national significance identified in the Wet Tropics bioregion. Wet Tropics freshwater systems contain extremely rich biodiversity. For instance, 80 of the 190 species of Australian freshwater fish can be found in the Wet Tropics. Freshwater systems are a preferred habitat for 30 frog species, 16 reptile species and 73 bird species.
Regional Ecosystems incorporate many types of aquatic ecosystems and their specific vegetation such as mangroves, melaleuca swamps, wetland grasses and some riparian vegetation. However Regional Ecosystems do not adequately accommodate larger, linear water bodies such as rivers, lakes, dams and estuaries. Aquatic ecosystems also have special qualities such as their linear connectivity across the landscape and the inherent variability of water flows. The linear nature of aquatic ecosystems means that they also have the capacity to move and accumulate threatening processes such as siltation and pollution across large distances. For example, run off from upland agriculture affects the Great Barrier Reef.
Rivers are also closely associated with scenic and recreational values, especially waterfalls, swimming holes and rapids used for rafting. They are also used for fishing and the Wet Tropics contains some commercial enterprises such as barramundi farms.
You can read more about freshwater ecosystems and their plants and animals in the publications and links below: