Meadows Creek, near Kuitpo Forest
2010 Aquatic Ecosystem Condition Report
- Permanently wet with a non-flowing channel in autumn and a flowing freshwater creek with riffles present in spring.
- Moderately diverse macroinvertebrate community with some rare and sensitive species.
- Obvious signs of moderate nutrient enrichment.
- Riparian vegetation was mainly native species but included some woody weeds.
About the location
Meadows Creek is a moderately large stream in the southern Mount Lofty Ranges that rises to the north of Meadows and flows in a southerly direction, where it eventually discharges into the Finniss River. The major land uses are cattle grazing and cropping, and minor areas of irrigated crops such as strawberries.
The monitoring site was located on Tynan Road, less than one kilometre west of Kuitpo Forest.
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 fine sediment deposition, although the stream still provided an important refuge for a few sensitive macroinvertebrate species.
A moderately diverse community of about 34 species of macroinvertebrates was collected from the creek, ranging from 5–7 metres wide and up to 40 centimetres deep, in autumn and spring 2010. The creek consisted of a non-flowing channel in autumn and a flowing channel with large areas of fast-flowing riffle habitats in spring. The community was dominated by large numbers of a few species that are tolerant to poor water quality, such as hydrobiid snails, amphipods (Austrochiltonia australis) and chironomids. It also included smaller numbers of flatworms, snails (including the introduced Physa and Potamopyrgus antipodarum), bivalves, leeches, worms, mites, freshwater shrimps, beetles, mosquitoes, biting midges, blackflies, mayflies and waterbugs. At least two sensitive species of mayflies (Atalophlebia australis and Koorrnonga inconspicua) and two flow-dependent species (blackfly Simulium and dytiscid beetle Platynectes decempunctatus) were recorded, generally from the riffle habitats in spring.
The water was fresh to moderately fresh (salinity of 474–1,154 mg/L), poorly to well oxygenated (24–87% saturation), slightly coloured and turbid in autumn but clear in spring, with moderate to high concentrations of nutrients such as nitrogen (0.98–1.27 mg/L) and phosphorus (0.05–0.15 mg/L).
The sediments were dominated by cobbles, gravel, sand, silt and clay in the riffles and cobbles, algae, sand and detritus in the non-flowing habitats. Samples taken from below the surface were black and sulfidic in autumn and well aerated in spring when the creek was flowing strongly. A deposit of 1-5 centimetres of silt covered the creekbed in autumn and a small area of bank erosion was recorded in both seasons, due to the effects of floods and stock damage.
A moderate amount of phytoplankton was recorded in autumn and filamentous algae (Spirogyra) covered less than 10% of the site in both seasons sampled. Aquatic plants covered over 10% of the channel and comprised several emergent species (Callitriche, Crassula, Cyperus, Juncus, Phragmites, Typha, Rumex and Isolepis).
The narrow riparian zone consisted of the Common Reed (Phragmites australis) and introduced blackberries and grasses under a canopy of gum trees and acacias. The surrounding vegetation at the site was largely grazed grassland and irrigated strawberry fields.
Special environmental features
Meadows Creek provides habitat for at least two sensitive species of mayflies and a few flow-dependent species of macroinvertebrates. Recent fish surveys in the catchment have also recorded the presence of at least two threatened fish species (Mountain Galaxias and Southern Pygmy Perch) from the mid to lower sections of the creek (M Hammer, Aquasave Consultants, 2009).
Pressures and 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.|
|Insufficient natural water flows resulting from water extraction and climate variability (reducing ecological integrity.||The SA Murray–Darling Basin NRM Board is working with the Department for Water and the community to develop a water allocation plan and licensing system which aim to balance social, economic and environmental needs for water. The objective for providing water to the environment is to maintain and/or restore self-sustaining water-dependent ecosystems which are resilient in times of drought.|
|Widespread introduced trees and weeds in the riparian zone at the site and upstream in the catchment (reducing habitat quality).||The SA Murray–Darling Basin NRM Board recognises the limitations of available funds relative to the scale of the degradation caused by introduced trees and weeds. The NRM Board provides free technical advice and community education to assist land managers in dealing with the integrated management of aquatic weeds. The NRM Board also has a targeted process, as directed by State Government, to strictly prioritise its investment in weed control activities as funds are limited. The NRM Board actively seeks funding opportunities for weed control; most opportunities are for locations where biodiversity outcomes can be achieved.|