Riparian vegetation mostly native trees over introduced grasses.
Area map
About the location
Baker Creek is a small stream in the eastern Mount Lofty Ranges. It rises south of Mount Pleasant, flows in a southerly and then heads east where it ultimately discharges into Reedy Creek. The major land use is sheep grazing. The monitoring site was located on a track off Camels Hump Road, over two kilometres south of Palmer.
The creek was given a Fair rating because the site sampled showed moderate changes in ecosystem structure and some changes to the way the ecosystem functions. There was evidence of human disturbance, including nutrient enrichment and degraded riparian habitat.
Findings
A sparse community of about 21 species of macroinvertebrates was collected from the flowing creek, seven metres wide and up to 50 cm deep, in spring 2010; the site was dry in autumn. The community was dominated by large numbers of species that are tolerant to poor water quality such as chironomids (including Cricotopus, Chironomus and Dicrotendipes) and notonectid waterbugs (Anisops) in the still water sections and blackfly larvae and dytiscid beetles in the flowing riffle habitats. The community also included smaller numbers of mites, amphipods, freshwater shrimp, beetles, biting midges (Bezzia), damselflies, stoneflies and caddisflies. The only rare species collected was a single stonefly (Riekoperla naso) specimen from the riffle habitat in spring. Several other species that are often associated with flowing waters were collected including blackfly larvae (Simulium ornatipes), dytiscid beetle larvae (Platynectes decempunctatus) and whirligig beetles (Gyrinidae).
The water was moderately fresh (salinity of 2,402 mg/L), well oxygenated (80% saturation) and slightly coloured, with moderate to high concentrations of nutrients such as nitrogen (1.16 mg/L) and phosphorus (0.03 mg/L).
The sediments were dominated by cobbles, sand and algae in the riffle and gravel, sand and cobbles in the pools. There was no evidence that the sediment was lacking in oxygen.
Filamentous algae (Spirogyra) covered more than 10% of the channel in spring. Small patches of emergent plants (Cyperus, Juncus, Typha and Carex) were also present and covered slightly less than 10% of the channel. The riparian zone consisted of gum trees, melaleucas and acacias over introduced grasses and sedges. The surrounding vegetation was mostly introduced grasses, and patches of native vegetation (yakkas, acacias and gums).
Special environmental features
Baker Creek provides habitat for a rare species of stonefly (Riekoperla naso) that only occurs in parts of South Australia (eg Mount Lofty Ranges, Fleurieu Peninsula, Kangaroo Island and the lower Flinders Ranges).
Recent fish surveys in the region indicate that a few permanent pools further upstream in Baker Creek may be the major refuge habitats for the threatened Mountain Galaxias within the Reedy Creek catchment (M Hammer, Aquasave Consultants, 2009).
Pressures and management responses
Pressures
Management responses
Livestock have direct access at the site and upstream, causing sediment erosion and adding excessive nutrients (which leads to habitat disturbance, algal growth and aquatic weeds).
The SA Murray-Darling Basin NRM Board acknowledges the significant impacts that livestock have on aquatic environments and seeks to provide free technical advice and incentives to land managers for fencing and other works as funding permits. Funding incentives are limited in value and extent and require land managers to volunteer to be involved.
Limited riparian vegetation at the site and upstream, providing minimal buffer protection from catchment landuses (reducing habitat quality).
The SA Murray-Darling Basin NRM Board recognises that the management of riparian vegetation requires a long-term, integrated approach to achieve ecosystem benefits. The board therefore provides free technical advice on a range of topics for land managers and various incentives for works as funding permits.
Observed Condition
Expected Condition
