Artimore Creek, Nildottie Spring
2012 Aquatic Ecosystem Condition Report
- Permanent, shallow flowing stream in autumn but contracted to isolated in-stream pools when sampled in spring 2012
- Moderately diverse macroinvertebrate community with several flow-dependent species present
- Water was moderately fresh, clear and generally low in nutrient concentrations despite showing signs of nutrient enrichment
- Riparian vegetation consisted of native trees and shrubs and the creek was covered by filamentous algae and aquatic plants
About the location
Artimore Creek is a small stream that rises near Patawarta Hill in the Northern Flinders Ranges and flows south-east, for about 35 km, where it discharges into Wirrealpa Creek. This stream then drains into Balcoracana Creek which eventually disappears underground on the plains surrounding the southern part of Lake Frome; flow rarely extends onto the plains except during exceptionally wet years. The only land use in the 4,070 hectare catchment, upstream from the site sampled, was grazing natural vegetation. The monitoring site was located off a track from the Blinman to Wirrealpa Road, about 13 km north-east from Blinman.
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 stock and feral animals accessing the banks but the stream provides habitat for several flow-dependent and sensitive species of macroinvertebrates.
A moderately diverse community of at least 29 species of macroinvertebrates was collected from the creek, 2.7-2.8 m wide and up to 25 cm deep, in autumn and spring 2012. The creek consisted of non-flowing pools connected by small areas with flowing riffle habitats in autumn but contracted to smaller, isolated pools in spring. The community was dominated by moderate numbers of baetid mayflies (Cloeon) and chironomids (Procladius, Cricotopus, Tanytarsus and Chironomus) in autumn but no species was abundant in spring. Other species collected included mites, beetles (Platynectes decempunctatus, Allodessus, Necterosoma, Eretes, Hyphydrus elegans, Sternopriscus multimaculata, hydrophilid larvae and Scirtidae), mosquitoes (Culex and Anopheles), biting midges (Bezzia), blackflies (Simulium ornatipes), other flies (Tabanidae and Stratiomyidae), waterbugs (Diaprecoris barycephala, Microvelia, Agraptocorixa and Anisops), dragonflies (Hemianax and Hemicordulia) and caddisflies (Triplectides australis, Hellyethira simplex and Cheumatopsyche).The lack of snails and crustaceans was unexpected given the range of habitat types present, and may indicate that the stream is too shallow and ephemeral to support most non-insect groups at the site sampled. Despite this, the stream did support a range of flow-dependent species, including blackflies (Simulium), dytiscid beetles (Platynectes) and caddisflies (Cheumatopsyche). The mayfly was the only sensitive but widely distributed species collected. Most species were, however, generalists and tolerant insect groups that are capable of dispersing aerially to other wetted habitats in the region.
The water was moderately fresh (salinity ranged from 1,702-2,221 mg/L), well oxygenated (72-105% saturation) and clear, and with low to moderate concentrations of nutrients such as phosphorus (0.02 mg/L) and nitrogen (0.41-0.57 mg/L).
The sediments were dominated by bedrock, pebble, gravel and algae, with smaller amounts of cobble, sand, silt and detritus also present; samples taken from below the surface were grey sands and gravels that were sulphidic in spring when the stream ceased flowing, indicating that they were anaerobic, or lacking in oxygen. No evidence of any significant bank erosion was noted but a range of animal faeces was recorded from the channel and edges of the creek, including goats, sheep, kangaroos and emus.
A small amount of phytoplankton was present in spring (chlorophyll a 1.23 Âµg/L) and over 35% of the shallow margins of the creek was covered by filamentous algae (Cladophora and Spirogyra) in autumn. Several species of aquatic plants were recorded from the stream including submerged (Chara and Nitella) and emergent plants (Cotula, Cyperus and Juncus). The riparian vegetation was dominated by River Red Gums over sedges on the moderately well vegetated banks (50-79% vegetative cover). The surrounding vegetation at the site comprised low native woodland dominated by eucalypts, White Cypress Pines and wattles.
Special environmental values
Artimore Creek is a largely natural, permanent stream in the North Flinders Ranges that provides habitat for a wide range of aquatic macroinvertebrate species, including several flow-dependent species and some long-lived pool species. The stream also supports large numbers of frogs and a largely natural vegetation assemblage.
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.
|Livestock have direct access at the site and upstream, causing sediment erosion and adding excessive 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.