Riparian vegetation consisted of native trees and shrubs, and an aquatic plant occurred in patches around the edges of the waterhole
Area map
About the location
Cooper Creek is a large stream in the Far North that rises at an altitude of 230m in western Queensland and flows south-westerly for over 1,500 km through increasingly arid woodland, grassland and desert before discharging into Lake Eyre. In the ‘channel country’ of the middle reaches it forms both deep, narrow channels which transport sand and mud at moderate flows and a large network of braided channels that transport clay-rich mud during high flow periods. As the river passes into South Australia it forms the one channel near Innamincka and then further downstream it extends across a wide floodplain and forms another mosaic of shallow freshwater and saline lakes, deep permanent and semi-permanent channel reaches, flooded woodlands and grasslands, samphire-lined claypans and other wetlands (for more details see Walker et al. 1997 and Silcock 2009 under the Further Information heading). Flow patterns in the unregulated Cooper Creek are highly variable and driven by monsoonal summer rainfall in the upper catchment area in Queensland. Most water is retained or evaporates in the channel country and only 30% of overbank flows reaches Innamincka. As a result, Lake Eyre only receives water during extremely large floods.
The major land uses in the 296,000 square kilometre catchment are sheep (Qld only) and cattle grazing on native grasslands, with smaller areas used for rural towns and settlements, mining, tourism and national parks.
The monitoring site was located in the Coongie Lakes National Park off Coongie Track, about 85 km north-west from Innamincka.
The creek was given a Fair rating because the site sampled showed evidence of moderate changes in ecosystem structure, and some changes to the way the ecosystem functions. There was evidence of human disturbance including nutrient enrichment but the stream still provided habitat for a rare snail and chironomid and a range of other aquatic species. Note that the high nutrient concentrations recorded from the waterhole were similar to other sites sampled from Cooper Creek and were assumed to have originated from upstream grazing and cropping practices. Similarly, the high turbidity was sourced by floods naturally mobilising clays from the channel country in Queensland and was not obviously exacerbated by local land use practices.
Findings
A moderately diverse community of at least 11 species of macroinvertebrates was collected from the 100 m wide, non-flowing, arid-zone waterhole in spring 2012. The community was dominated by moderate numbers of waterbugs (Anisops and Micronecta) and included smaller numbers of 3 molluscs (Thiaridae, Glyptophysa and Ferrissia), 3 chironomids (Cricotopus, Coelopynia and Cladopelma), a freshwater prawn (Macrobrachium), a caddisfly (Triplectides australis) and oligochaete worms. The community included groups normally associated with stream environments (prawn and thiarid snail) and others that are typically found in pool habitats and temporary waters throughout the Far North region (insects such waterbugs, chironomids and caddisfly). The thiarid snail (Thiara) and chironomid (Coelopynia) were the only rare species to be recorded from the site. The waterhole was notable due to the absence of groups commonly found elsewhere along Cooper Creek, including beetles, mayflies, odonates and mites. A few freshwater mussel shells (Velesunio) were seen around the edge, which indicates this waterhole provides a refuge habitat for long-lived biota. A small number of introduced mosquitofish (Gambusia) were collected at the site but no native species of fish were observed.
The water was fresh (salinity of about 169 mg/L), well oxygenated (86% saturated) and turbid (secchi depth 11 cm), with high concentrations of nutrients such as nitrogen (2.92 mg/L) and phosphorus (0.6 mg/L).
The sediments were dominated by living and dead detritus, with smaller amounts of sand, silt and clay; samples taken from below the surface were anaerobic grey sands, indicating that the sediments were lacking in oxygen. No evidence of any significant bank erosion was noted and the large amount of rabbit droppings around the banks was the only evidence of animals accessing the waterhole.
A large amount of phytoplankton was present (chlorophyll a 28.9 µg/L) and included some blue-green algae (chlorophyll b 3.8 µg/L) but no filamentous alga was seen. About 10% of the waterhole was covered by a native aquatic plant called Water Primrose (Ludwigia peploides). The riparian vegetation was dominated gum trees acacias and patches of lignum on the poor to moderately vegetated banks (25-49% vegetative cover). The surrounding vegetation comprised low gum and acacia woodland.
Special environmental features
The waterhole lies within the Coongie Lakes Ramsar Wetlands which contains a diverse range of aquatic habitats, supports a huge number of breeding birds during favourable flood conditions, as well supporting many other significant plant and animal species in the region.
Pressures and management responses
Pressures
Management responses
High nutrient concentrations causing excessive algal growth although the source(s) of the nutrients are not known with certainty.
The EPA in collaboration with the Department for Environment, Water and Natural Resources is anticipating a study program to investigate the source(s) of nitrogen and phosphorus. This will provide a better understanding of nutrient dynamics with the aim of developing a management strategy (if appropriate).
Livestock have direct access at the site and upstream in the catchment exerting excessive grazing pressure on vegetation, causing sediment erosion and adding nutrients to the watercourse.
The SA Arid Lands Natural Resources Management Board recognizes that both direct and diffuse impacts on aquatic ecosystem condition can occur through direct stock access and excessive grazing pressure from stock and feral herbivores. Technical advice and incentives are offered to land managers in the region, as funding permits, to address these impacts through appropriate activities suitable for the context. In addition, projects are underway across the region to identify, prioritise and address impacts at key aquatic sites.
Silcock, J. (2009). “Identification of Permanent Refuge Waterbodies in the Cooper Creek and Georgina-Diamantina River Catchments for Queensland and South Australia.” Final report to South Australia Arid Lands Natural Resource Management Board.
Walker, K.F., Puckridge, J.T. & S.J. Blanch (1997). Irrigation development on Cooper Creek, central Australia – prospects for a regulated economy in a boom-and-bust ecology. Aquatic Conservation: Marine and Freshwater EcosystemsVolume 7, pages 63-73.
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Observed Condition
Expected Condition
