Areas of Identified Conservation Significance
Tarrabool Lake is one of Australia’s largest wooded swamps, located about 160km north-east of Tennant Creek. The Lake waters most frequently occupy an inner basin of about 400km² but the extent of the flooded area varies enormously from year to year depending on that season’s rainfall. In exceptionally wet years the Lake will join with Eva Downs Swamp in the north to cover an area of over 2750km², forming one of the largest freshwater wetlands in inland Australia. Tarrabool Lake is unique in its Eucalyptus coolibah dominance, providing it with a wooded area of at least 1200km². The Lake supports large areas of grassland, open lignum and bluebush shrubland.
Lake Sylvester is one of the biggest and most outstanding natural freshwater wetlands of inland Australia, with regards to both its physical and biological features. Lake Sylvester is located approximately 180km east-north-east of Tennant Creek and comprises four primary basins (Sylvester, Corella, De Burgh, and an unnamed basin to the west of Corella). The size of the inner basins of individual lakes vary from 100 to 300km², but in exceptionally wet years the lakes form into a single lake with an area of about 2,000km². These lakes provide diversity of wetland habitats, including broad areas of grassland, lignum and bluebush shrublands, as well as fringing areas of open eucalypt and acacia woodland.
Lake Woods is large ephemeral wetland located on the western edge of the Barkly Tableland, approximately 220km north of Tennant Creek. Lake Woods commonly occupies an area of approximately 350km², but during periods of major flooding it joins with the lower reaches of Newcastle Creek and can nearer 1000km² – making it one of the largest temporary freshwater lakes in the Northern Territory and tropical Australia. The Lake basin supports grass and sedge communities, including the largest areas of lignum swamp in the Northern Territory. The northern edge of the Lake and Newcastle Creek are fringed by river red gum and Eucalyptus coolibah.
The above four locations have all been identified as High Conservation Value Aquatic Ecosystems (HCVAE) and sites of international conservation significance. Three other sites of national significance that are located within the Barkly Tableland include part of the Davenport and Murchison Ranges, the Frew River floodout swamp and part of the Wollogorang and China Wall Sandstone Ranges.
The Georgina River Catchment is a major headwater of the expansive Lake Eyre Basin. The Georgina catchment area is positioned across the Northern Territory and Queensland with a total basin area of approximately 232,000km² (almost the size of the entire state of Victoria). The Georgina is fed by the Ranken River and James River in the Northern Territory and the Buckley River flowing in from Queensland as well as a significant network of streams and smaller tributaries. However due to the arid nature of the environment here, the mean annual flow of the Georgina basin is only about 0.7km3. With vast areas of Mitchell grass downs country on black cracking clay soils, like most of the e Barkly Tableland, the Georgina catchment supports a significant pastoral production industry.
Threats to the Barkly
Invasive weeds are among the most serious threats to Australia’s natural environment and primary production industries. Weeds species displace native species, contribute significantly to land degradation, and reduce land productivity. Considerable amounts of time and money are spent each year combating weed infestations and protecting unique ecosystems and primary production regions such as the Barkly Tableland.
Feral animals can substantially affect a region’s biodiversity. Ferals can potentially impact on native fauna in multiple ways, including direct predation, competition for food and habitat, direct destruction of habitat and spread of disease. In Australia, feral animals typically have few natural predators or fatal diseases and some have high reproductive rates. As a result, their populations have not naturally diminished and they can multiply rapidly if conditions are favourable.
In addition to the direct impacts on Australian biodiversity, the far-reaching carryon impact from feral animal leads to pressures and major implications on soil landscapes, waterways, native plants and animals. Find out more information on feral animals within the Northern Territory here.