Riparian vegetation consisted of native trees and shrubs, and an aquatic plant occurred 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). 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 Innamincka Regional Reserve off the 15 Mile Track, about 10 km south-west from Innamincka.
In summary
The creek was given a Good rating because the site sampled showed evidence of relatively minor changes in ecosystem structure and function. There was evidence of human disturbance due to nutrient enrichment but the stream provides habitat for a range of aquatic species, including several rare and sensitive species of macroinvertebrates. 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 15 species of macroinvertebrates was collected from the 70 m wide, non-flowing, arid-zone waterhole in spring 2012. The community was dominated by moderate numbers of several species of chironomids and included smaller numbers of waterbugs (Anisops and Micronecta), mayflies (Cloeon and Tasmanocoenis tillyardi), and a hydrophilid beetle, biting midge (Culicoides) and freshwater prawn (Macrobrachium). An empty viviparid shell (Centrapala) was collected and several empty mussel shells (Velesunio) were also seen around the edge of the waterhole. The rich assemblage of chironomids (Cladopelma, Cladotanytarsus, Coelopynia, Dicrotendipes, Tanytarsus, Larsia, Polypedilum and Parachironomus) was unusual for an arid zone site and the absence of odonates, caddisflies and mites was unexpected given the range of habitat types present at the site sampled. The only groups normally associated with stream environments were the prawn, thiarid snail, viviparid, mussel and possibly chironomid Cladotanytarsus, whereas the other species collected are typically found in pool habitats and temporary waters throughout the Far North region. The thiarid, viviparid and one of the chironomids (Coelopynia) are rare species and the mayflies are both widely distributed but sensitive species that are typically found from the more permanent freshwater habitats in the region. No fish were caught or seen at the site when it was sampled in November 2012.
The water was fresh (salinity of about 130 mg/L), well oxygenated (98% saturated) and turbid (secchi depth 8 cm), with high concentrations of nutrients such as nitrogen (2.58 mg/L) and phosphorus (0.53 mg/L).
The sediments were dominated by detritus, sand, silt and clay; samples taken from below the surface were grey sands and showed no signs that the sediments were anaerobic, or lacking in oxygen. No evidence of any significant bank erosion was noted and no animal faeces were recorded from the edges or bank surrounding the waterhole.
A moderate amount of phytoplankton was present (chlorophyll a 6.9 µg/L) and a small amount of filamentous algae was recorded. About 10% of the waterhole was covered by a native aquatic plant called Water Primrose (Ludwigia peploides). The riparian vegetation was dominated gum trees and lignum, with patches of acacias and sedges (Cyperus) on the moderately vegetated banks (50-79% vegetative cover). The surrounding vegetation comprised low gum and acacia woodland.
Special environmental features
The more permanent waterholes and channel reaches on Cooper Creek provide an important refuge habitat for a wide range of arid-zone fish (Cockayne et al. 2013). While no fish were noted during the present work, the waterhole probably supports a number of fish species for extended periods following flood events.
Pressures and management responses
Pressures
Management responses
High nutrient concentrations causing excessive algal growth although the source(s) of all the nutrients is 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).
Recreational camping near the waterhole may be causing erosion, contributing to litter and weed dispersal.
The SA Arid Lands Natural Resources Management Board acknowledges the impact of uncontrolled tourism on private lands in the region, particularly where priority aquatic are subject to frequent camping visits. A trial is currently underway for an assessment tool which describes cultural, ecological and social features associated with aquatic sites as well as identifying impacts and prioritising management interventions, such as fencing and interpretive signage. In addition, an education program targeting the tourism industry is being planned, funding dependent, to help improve understanding of ecological impacts and to raise awareness about more appropriate, lower-impact behaviours
Livestock in the catchment are exerting excessive grazing pressure on vegetation and causing sediment erosion.
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.
Cockayne, B., Schmarr, D., Duguid, A. & R. Mathwin (2013). “Lake Eyre Basin Rivers Assessment (LEBRA) 2012 Monitoring Report.” Report to LEBRA Oversight Group.
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
