Balcanoona Creek, Weetootla Campground
2012 Aquatic Ecosystem Condition Report
- Isolated pools in autumn and dry in spring 2012
- Moderately diverse macroinvertebrate community that included snails and mayflies
- Water moderately fresh, clear and low in nutrients
- Riparian vegetation consisted of native trees and shrubs over a few weeds
About the location
Balcanoona Creek is a large stream that rises off the southern side of the Blue Range in the Vulkathunha-Gammon Ranges National Park and flows in an easterly direction for 65 km through Weetootla Gorge and across Balcanoona Ranges, eventually discharging onto the plains surrounding the north-western edge of Lake Frome; flow only extends onto the plains during exceptionally wet years. The only land use in the 3,045 hectare catchment, upstream from the site sampled, is national park. The monitoring site was located off Weetootla Trail from Arkaroola Road, about 6 km north-west from Balcanoona.
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 including nutrient enrichment and weedy riparian zones but the stream provides habitat for several rare and sensitive species of macroinvertebrates.
A moderately diverse community of at least 21 species of macroinvertebrates was collected from the creek, 5.8 m wide and up to 25 cm deep, in autumn; the site was dry in spring 2012. The creek consisted of shallow, isolated pools when wet. The community was dominated by moderate numbers of mosquitoes (Anopheles) and included smaller numbers of snails (Austropeplea and Pygmanisus), beetles (Sternopriscus, Necterosoma penicillatus and Eretes), biting midges (Bezzia), tabanid flies, chironomids (Procladius, Larsia, Tanytarsus and Chironomus), mayflies (Cloeon and Tasmanocoenis tillyardi), waterbugs (Mesovelia, Agraptocorixa and Anisops), odonates (Ischnura, Hemianax and Hemicordulia) and caddisflies (Triplectides australis). The presence of two snails and two mayflies was notable for the site as few streams in the Flinders Ranges supported these rare and/or regionally sensitive species in 2012. Most species collected were, however, widely found generalist and tolerant insect groups, capable of aerially dispersing between wetted habitats throughout the region. The site lacked any mites or crustaceans, presumably because the stream dries on occasion; the snails and mayflies, in contrast, are probably able to refuge in the wet sediments under the large rocks found in the creekbed.
The sediments were dominated by filamentous algae and detritus, with smaller amounts of boulder, cobble, gravel, sand, pebble and silt also present; samples taken from below the surface were grey sands that showed no signs that the sediments were anaerobic, or lacking in oxygen. No evidence of any significant bank erosion was noted and the only animal faeces recorded from the edges of the waterhole were from kangaroos and emus.
A small amount of phytoplankton was present (chlorophyll a 2.1 Âµg/L) and over 35% of the shallow margins of the creek was covered by a filamentous alga (Cladophora). About 10% of the creek was covered by two species of aquatic plants (sedge Cyperus gymnocaulos and cumbungi Typha), indications that the site regularly holds water for extended periods. The riparian vegetation was dominated by River Red Gums, paperbarks and acacias over native shrubs, sedges and weeds (Salvation Jane) on the poorly vegetated banks (25-49% vegetative cover). The surrounding vegetation at the site comprised low native woodland dominated by eucalypts, native pines and wattles.
Special environmental features
Balcanoona Creek is a largely natural, ephemeral stream in the Vulkathunha-Gammon Ranges National Park. Few human disturbances are evident due in part to the remote location although large herds of goats and other animal pests such as rabbits occur in the area on occasion. The main feature of the site in autumn 2012 was the presence of two species of snail and the two commonly occurring mayfly species from the region. This section of Balcanoona Creek and the inflowing Weetootla Creek just upstream, also provide significant habitat for the endangered Northern Purple-spotted Gudgeon.
Pressures and management responses
|Feral goats, donkeys and rabbits are exerting excessive grazing pressure on vegetation, causing erosion and adding excessive nutrients to the watercourse.||The SA Arid Lands Natural Resources Management Board provides technical advice and incentives for the management of introduced weeds and feral pest animals, as funding permits. Pest management efforts are guided by a region-wide strategy, based on risk assessment, to determine priority locations and species. Funding is actively sought from a number of sources to support region-wide integrated management.|