Riparian vegetation dominated by willows and gum trees over fruit trees and weeds
Fine sediment deposits smothered streambed in places
Area map
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 in the catchment are dairying, livestock grazing, vineyards, forestry plantations, and rural living areas. The monitoring site was located off Wicks Road, about 5 kilometres south-west from Meadows.
The creek was given a Fair rating because the site sampled showed evidence of moderate changes in ecosystem structure, and some changes to the way the ecosystem functions. There was evidence of human disturbance including nutrient enrichment, fine sediment deposition and weeds dominating the understorey vegetation on the banks.
Findings
A moderately diverse community of at least 30 species of macroinvertebrates (14 species in autumn and 19 in spring) was collected from the non-flowing creek, up to 8 metres wide and over 1.4 metres deep, in autumn and spring 2015. The community was dominated by generalists and species tolerant to poor water quality such as amphipods (Austrochiltonia) in autumn and by amphipods, beetles, mosquitoes and chironomids in spring. It also included smaller numbers of other tolerant taxa such as water mites, snails (including native Glyptophysa and introduced Physiella), scirtid beetles, sciomyzids fly larvae, waterbugs, damselflies and caddisflies (Hellyethira simplex and Lectrides varians). The site lacked any sensitive or rare species, and the lack of flowing riffles meant that no flow-dependent macroinvertebrates were recorded at the site.
The water was fresh (salinity ranged from 942 - 2,119 mg/L), poorly to moderately well oxygenated (32-45% saturated), clear and slightly coloured in autumn, and with high concentrations of nutrients such as nitrogen (0.61-1.02 mg/L) and phosphorus (0.07 mg/L).
The sediments were dominated by dead and living detritus and included smaller amounts of sand, silt and clay, and filamentous algae was also noted in spring. More than 10 centimetres of fine sediment covered the bottom of the stream channel. Samples taken from below the surface were grey in colour and appeared well oxygenated in autumn but the sediments released sulfide when tested and lacked oxygen in spring, indicating they were a harsh environment for most burrowing species to tolerate. A small amount of bank erosion was present at the site due to past bank slumping, presumably caused during the recession of a recent flood.
A small to moderate amount of phytoplankton was recorded (chlorophyll a ranged from 0.9-4.6 µg/L) but filamentous algae was only seen in spring when Spirogyra covered less than 10% of the channel. Over 65% if the channel was covered by aquatic plants, including dense stands of cumbungi (Typha) and patches of submerged (Callitriche) and emergent species (Rumex). The riparian vegetation extended more than 30 m from the edge of the stream and comprised introduced willows and fruit trees and a few native gums over various woody weeds (mostly wild roses and gorse). The surrounding vegetation at the site was rural gardens with a range of planted and native plants present.
Special environmental values
None detected in 2015.
Pressures and management responses
Pressures
Management responses
Livestock have direct access to some creeks, causing sediment erosion and adding excessive nutrients (which leads to habitat disturbance, algal growth and aquatic weeds).
Natural Resources SA Murray–Darling Basin 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 some creeks, providing minimal buffer protection from catchment landuses (reducing habitat quality).
Natural Resources SA Murray–Darling Basin recognises that the management of riparian vegetation requires a long-term, integrated approach to achieve ecosystem benefits. The NRM 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).
A water allocation plan that guides sustainable water use in the Eastern Mount Lofty Ranges has been developed by Natural Resources SA Murray–Darling Basin, working with the community and government (particularly the Department for Environment, Water and Natural Resources (DEWNR)). The plan aims to balance social, economic and environmental water needs and is implemented through a system of water licensing and permits for water affecting activities administered by DEWNR.
A key component of the water allocation plan is to provide water to sustain the environment at an acceptable level of risk. Securing low flows for the environment is a key environmental water provision in this area, and Natural Resources SA Murray–Darling Basin is working together with DEWNR, Natural Resources Adelaide and Mount Lofty Ranges and the community to develop a program to secure low flows across the Mount Lofty Ranges. For more information on water allocation planning and associated projects go to our Water Allocation Planning web page.
Widespread introduced trees and weeds in riparian zones (reducing habitat quality).
Natural Resources SA Murray–Darling Basin recognises the limitations of available funds relative to the scale of the degradation caused by introduced trees and weeds. It 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. It actively seeks funding opportunities for weed control; most opportunities are for locations where biodiversity outcomes can be achieved.
Observed Condition
Expected Condition
