Italowie Creek, Italowie Gap
2012 Aquatic Ecosystem Condition Report
- Dry watercourse in autumn and spring 2012
- Likely to be low in nutrient levels when wet because the catchment is largely in a national park
- Some bank erosion caused by flood damage and goats accessing the site in spring
- Riparian vegetation consisted of native trees and shrubs
About the location
Italowie Creek is a small stream that rises in the Blue Range within the Vulkathunha-Gammon Ranges National Park and flows south-east, where it merges with Mount McKinlay Creek to form Big John Creek, which eventually discharges onto the plains on the western side of Lake Frome; flow only extends onto the plains during very wet years. The only land use in the 3,548 hectare catchment, upstream from the site sampled, is national park. The monitoring site was located in Italowie Gorge off Copley Road, about 14 km 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 feral animals accessing the banks and weedy riparian zones but the ephemeral stream provides largely natural habitat features that are dominated by native plants.
The sediments were dominated by bedrock, boulder, cobble and pebble, with smaller amounts of gravel, sand, silt and detritus also present. Samples taken from below the surface were grey sands and showed no signs that the sediments were recently anaerobic, or lacking in oxygen. About 10 m of bank showed evidence of erosion due to past floodwater damage. Feral goats and kangaroos had defaecated in the channel and may also have contributed to localised bank damage.
A few sedges (Cyperus gymnocaulos) were recorded from the channel but no other aquatic plants or any algal remnants were observed during either inspection of the creek. The riparian vegetation was dominated by River Red Gum and acacias over native shrubs, sedges and a range of weeds and grasses on the moderately well vegetated banks (50-79% vegetative cover). The surrounding vegetation at the site comprised native woodland dominated by eucalypts, casuarinas, native pines and wattles.
Special environmental values
Italowie 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 and plant pests obviously occur in the area. No significant environmental values were recorded from the dry site visited in 2012 but previous sampling in the early to mid 1990’s indicated the site could support a wide range of aquatic species when the creek flows, including many flow-dependent macroinvertebrates (e.g. blackflies, Dasyhelea biting midges, empidid larvae) and several mayflies (Cloeon and Tasmanocoenis) and caddisflies (Hellyethira, Hydroptila, Ecnomus and Triplectides).
Pressures and management responses
|Feral goats and donkeys 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.|