Boundaries

This ecoregion is delimited by the drainages that flow east, west, and south from the Central Tasmanian Highlands. The specific boundaries are south from the George River in the northeast, then west and north around the Tasmanian coastline to the Arthur River in the northwest.

Topography

This ecoregion is mountainous with elevations of up to 1600 m asl. It includes the Central Mountain Ranges in the north, the Princess Range in the west, and the Frankland Range in the southwest.

Freshwater habitats

This ecoregion is the smallest in Australia, covering only 36,000 square kilometers. Rivers, streams, lakes, lagoons, wetlands, and estuaries all occur in this ecoregion. Given the rugged topography, most rivers are swift-flowing and have rocky beds. This is only one of two Australian ecoregions with a significant number of natural permanent lakes. All of these lakes were formed due to the influence of repeated glaciation in Tasmania over the last 2 million years (Colhoun & Peterson 1986). Many of these natural lakes have been modified to increase their size.

Terrestrial habitats

Terrestrial vegetation includes wet and dry sclerophyll woodland and grasslands at lower elevations, grading into alpine and coniferous forest at higher elevations (World Wildlife Fund 2001a). Temperate rainforest occurs in the wetter, western portion of the ecoregion (World Wildlife Fund 2001b).

Description of endemic fishes

All of the ecoregion’s endemic fish species are from the Galaxiidae family (Galaxias auratus, golden galaxias; G. johnstoni, Clarence galaxias; G. parvus, swamp galaxias; G. pedderensis, pedder galaxias; Paragalaxias dissimilis, Shannon paragalaxias; P. eleotroides, Great Lake paragalaxias; and P. julianus, Julian paragalaxias). Each of these endemics has a relatively small natural range.

Justification for delineation

This ecoregion has an endemic fauna that appears to have largely evolved in situ. All of the endemic species found here have restricted ranges, often in only one or a few lakes or streams. The isolation of this region is likely due to its location at the far southern end of Australia and effective ocean barriers due to a narrow continental shelf (Unmack 2001).

Level of taxonomic exploration

The level of taxonomy is good as most species appear to be relatively well known. Most species are diadromous and thus have wide natural ranges.