Biodiversity is the variety of all life forms: the different plants, animals and micro-organisms, their genes and the ecosystems of which they are a part. There are three widely recognised levels of biodiversity - entire ecosystems, the species which interact to make up ecosystems and genetic differences within each species.
More recently, studies on irreplaceability, uniqueness and rarity have argued that these qualities should be essential when assessing the Outstanding Universal Value of a World Heritage property. The Wet Tropics World Heritage Area was ranked sixth among all global sites and second among World Heritage sites for its irreplaceable endemic species and threatened species. You can read more in our Irreplaceable and Outstanding eBulletinn article.
In 2010 the forests of eastern Australia (from the Wet Tropics to northern New South Wales) were recognised as one of 35 international global biodiversity hotspots. To be recognised as a hotspot a region must first have more than 1,500 endemic vascular plants and more than 70% of its original (pristine) native vegetation must have been lost or significantly degraded. This shows the importance of places like the Wet Tropics World Heritage Area which retains much of its original biodiversityand a wealth of endemic plants and animals.
The Wet Tropics World Heritage Area is famous for the rainforests which cloak its rugged mountain ranges and some coastal and tablelands areas. The Area also contains numerous other vegetation communities such as wet sclerophyll forests, open woodlands, riverine communities, melaleuca swamps, wetlands, coastal scrub and mangroves (see plant communities). Soils in the Area are predominantly derived from granites and rhyolites, and metamorphic sedimentary rocks. There are also some soils associated with basalt flows in the Atherton Tableland area and the coastal lowlands have extensive alluvial plains where soils can be over 60 metres deep (see geology and ancient landscapes).
The World Heritage Area (894,420ha) forms the core of the Wet Tropics bioregion (1,849,725ha) and 77 percent of the bioregion maintains remnant vegetation. The bioregion (0.26 percent of the Australian continent by area) contains an extremely rich variety of Australian animals and plants, many of which are endemic, rare or threatened. Wet Tropics fauna includes at least 663 vertebrate animal species. Invertebrate fauna is the richest in Australia and includes 230 butterfly species, 135 dung beetle species and 222 species of land snails. The ancient rainforests conserve an extraordinary diversity of plants including ferns, cycads and conifers which evolved over 200 million years ago. The Wet Tropics contains 16 of the 28 ancient lineages of primitive flowering plants, more than anywhere else in the world.
The World Heritage Area (0.12 percent of Australia by area) contains over 2,800 vascular plant species of which over 700 are restricted (endemic) to the Area. The Area contains:
You can learn about the unique biodiversity of the Wet Tropics on the following web pages: