What Makes Australian Wildlife Special?
Nature & People
The natural habitats of the New South Wales section of the Great Eastern Ranges corridor contain:
- 59% of the vulnerable and endangered fauna species in NSW
- 64% of the endangered and vulnerable flora species in NSW
- 70% of the vegetation classes in NSW
- Many endangered ecological communities.
All this is contained in an area of 10,995,678 hectares (less than 14% of NSW) extending across all land tenures, illustrating the extraordinary importance of the Great Eastern Ranges as a refuge for biodiversity in the face of climate change and other threats.
Endemism
An 'endemic' species is one restricted to a particular geographic region. Endemic species are often not well adapted to change, due to their reliance on their localised habitats. Many species have undergone habitat 'retraction' and 'fragmentation' as a result of recent human activity such as land clearing, which negatively alters the continuity of habitats that many species need to survive.
The Broad-headed Snake (Hoplocephalus bungaroides) is an endemic species restricted to a sandstone landscape, 250 km from Sydney. This species has very specific habitat and biological requirements that limit its adaptability to change and increase its scarcity. Similarly, the Dwarf Mountain Pine (Pherosphaera fitzgeraldii) grows exclusively in the splash zones of waterfalls in the Blue Mountains.
Refugia
A certain species or an entire ecosystem requiring a very specific set of conditions might be threatened by a change such as land clearing or a shift in climatic conditions. If these species or ecosystems have nowhere to go they face extinction. However, if they can move along a habitat corridor to a place with the right climate or other conditions the area available to them is known as a 'refugia' or refuge.
A refuge can become a place of habitat isolation containing relict populations of species that may have once been widespread. The Wollemi Pine (Wollemi nobilis) is a world-famous example of a species that has survived in refuge. As climatic conditions changed the Wollemi Pine's habitat was restricted to a small number of locations.
The Great Eastern Ranges contain a wider variety of landscapes – such as variations in slopes, aspect, rainfall, shelter, topography and soil types – than other areas in Australia, resulting in a greater range of refuge areas providing habitat to threatened species. Elevation changes from sea level to 2,228 m at Mount Kosciuszko, providing an opportunity for species to find habitats with favourable conditions. The ruggedness of the terrain creates microhabitats such as those along the Great Escarpment – including cliff faces, deep valleys, gorges, exposed ridgelines and waterfalls – protecting some species and ecosystems from threats such as fire and climate change.
Species Richness
'Species richness' refers to the number of species in a particular habitat or ecosystem. It indicates the variety of life in a particular area, and can indicate the sensitivity of the area to threats and pressures. A great example is the 'Green Cauldron' created by the rim of an ancient volcano in the Border Ranges of north-east NSW; the most biologically diverse region of the Great Eastern Ranges corridor in NSW. Wildlife here includes:
- 97 rainforest plant species.
- 31 fauna species.
- 1 threatened ecological community that includes the Double-eyed Fig-Parrot (Cyclopsitta diophthalma coxeni), the Richmond Birdwing Butterfly (Troides richmondia) and the Brush-tailed Rock-wallaby (Petrogale penicillata).
