Current view: Text account
Site description (2008 baseline):
Site location and context
The large ephemeral Lake Sylvester system is located on the Barkly Tableland 180 km north-east of Tennant Creek. The IBA comprises of Corella Lake, Lake de Burgh, Lake Sylvester, an unnamed basin to the west of Corella Lake, and a surrounding network of interconnected wetlands. It includes two semi-permanent freshwater billabongs, Corella Hole and Big Hole, which are located upstream from the deltas that mark the meeting points of Corella Creek and Corella Lake and Brunette Creek and Lake Sylvester, respectively. Corella Lake, Lake de Burgh and Lake Sylvester are ephemeral freshwater lakes. They are seasonally inundated, but can retain water for more than 12 consecutive months after substantial floods. At normal capacity, Corella Lake (10,000 ha), Lake de Burgh (30,000 ha) and Lake Sylvester (15,000 ha) are discrete water bodies. In wetter years, excess water from Corella Lake flows into the unnamed basin to the west (5000 ha), and all four basins can become full and connected. During exceptional flood events, such as that which occurred in 2001-2002, all water bodies present in the system can merge to form a single massive lake with an area of up to 200,000 ha. The Lake Sylvester system is situated on deep-cracking grey clay that supports sparse to open shrublands dominated by Northern Bluebush and Lignum, sparse to open woodlands and scattered specimens of Coolibah, stands of Belalie, tussock grasslands dominated by Rat's Tail Couch and Pepper Grass, carpet-like patches of Annual Verbine, and mats of the aquatic species Nardoo, Spiny Mudgrass and (infrequently) Potamogeton tricarinatus and Myriophyllum verrucosum (DEWHA 2007; R. Jaensch pers. comm. 2007).
At least 65 species of waterbird have been recorded in the Lake Sylvester system (Wetlands International unpublished data provided by R. Jaensch). Waterbirds recorded in notable but sub-threshold numbers include Freckled Duck (observed on all three named lakes, with up to 56 birds on Corella Lake, and breeding at Lake Sylvester; the only confirmed breeding locality in the Northern Territory), Great Egret (1000 pairs at Lake Sylvester in 2006), Intermediate Egret (1000 pairs at Lake Sylvester in 2006), Glossy Ibis (3000 pairs at Lake Sylvester in 2006, the largest documunted inland colony of this species in the Northern Territory and one of the largest documented colonies in tropical Australia), Oriental Pratincole (more than 15,000 individuals at Lakes Sylvester and de Burgh in 1993), Australian Pratincole (1350 individuals in 1995) and White-winged Black Tern (1700 individuals counted in 2002 but real total possibly many thousands). Little Curlew have been recorded in moderate numbers, but the species is difficult to survey and actual numbers are therefore likely to be globally significant (Jaensch and Bellchambers 1997; R. Jaensch pers. comm. 2007). Sub-threshold numbers of Nankeen Night-Heron, Royal Spoonbill, Little Black Cormorant, Pied Cormorant, Australasian Darter, Magpie Goose, Caspian Tern and Whiskered Tern are recorded to breed in the system (Wetlands International unpublished data provided by R. Jaensch). Yellow Chat occurs in aggregations of tens if not hundreds of birds (R. Jaensch pers. comm. 2007). There are historical records of the vulnerable Australian Painted Snipe from the Lake Sylvester system, Brunette Creek and Playford River. Evidence suggests the Australian Painted Snipe may still occur at least occasionally in the IBA: suitable habitat for the species is abundant at Lake Sylvester and in 1993 a positive sighting was made at Lake Woods, in habitat similar to that which occurs at Lake Sylvester, and breeding was documented at Tarrabool Lake, which lies approximately 60 km north-west of the Lake Sylvester system (Jaensch 2003; R. Jaensch pers. comm. 2007).
Non-bird biodiversity: The Lake Sylvester system supports two plant species, Bergia barklyana and Goodenia cylindrocarpa, which are endemic to the Mitchell Grass Downs bioregion (Harrison et al. 2009). A number of plant and vertebrate species recorded in the system are largely confined to cracking-clay grasslands within the Mitchell Grass Downs bioregion (Fisher et al. 2002). Four plant species present in the system (Commelina tricarinata, Senecio depressicola, Iotasperma sessilifolium and Urochloa atrisola) have a restricted range within the Northern Territory (Harrison et al. 2009).
Pressure/threats to key biodiversity
Develop a wetlands management strategy with landholders to identify additional stock exclusion areas and appropriate management of wetlands to maintain conservation values (NRETA 2005). This strategy could include protocols to monitor for Parkinsonia aculeata re-infestation, prevent major wildfires and regulate boating activity to minimise disturbance of waterbirds. In cooperation with landholders, assess the benefits of possible nomination of the system as a Ramsar site (NRETA 2005). Monitor and maintain fish stocks in waterways which feed the lake system.
Conservation responses/actions for key biodiversity
The three named lakes in the system are listed in the Directory of Important Wetlands in Australia (DEWHA 2007). The Lake Sylvester System is classified as a site of conservation significance by the Northern Territory Government (Harrison et al. 2009; Ward & Harrison 2009). The Lake Sylvester System and Corella Lake System are listed on the Register of the National Estate (Harrison et al. 2009). Lake Sylvester is acknowledged as an internationally important site for migratory shorebirds within the East Asian-Australasian Flyway (Bamford et al. 2008). Since 1993, Wetlands International have conducted infrequent surveys of waterbirds during and/or after flood events. An area of 100 ha on the margin of Lake Sylvester has been fenced to exclude livestock for research on vegetation management (R. Jaensch pers. comm. 2007), although the current state of the fence is unknown. Vegetation condition was monitored annually at transects in and around this fenced area during the 1990s. The landholder has greatly reduced, if not eliminated, Parkinsonia aculeata from this site. Six tier 1 rangeland monitoring points are located in the Lake Sylvester region. Fire on the tropical savannas is mapped continously under the North Australia Fire Information Project (Harrison et al. 2009; Ward & Harrison 2009).
None.
Pastoral lease (Brunette Downs) managed by Australian Agricultural Company.
Site access / Land-owner requests
Access can be arranged by contact with Brunette Downs station.
Roger Jaensch of Wetlands International provided review comments and interpretation on the habitat and waterbird information.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Lake Sylvester System (Australia). Downloaded from
https://datazone.birdlife.org/site/factsheet/lake-sylvester-system-iba-australia on 22/11/2024.
