Gould Creek, Macclesfield
2015 Aquatic Ecosystem Condition Report
Isolated pools present in autumn and dry in spring
Sparse macroinvertebrate community comprising tolerant and generalist species
Some evidence of moderate nutrient enrichment
Riparian vegetation dominated by introduced grasses and weeds under native gums and wattles
About the location
Also known as Doctor’s Creek, Gould Creek rises about four kilometres north of Macclesfield in the southern Mount Lofty Ranges. It flows south through mainly agricultural land used for livestock grazing (68%) and dairying (19%) to join the Angas River northwest of Strathalbyn. The site selected for monitoring was located off Macclesfield Road (also called Aldgate–Strathalbyn Road), about four kilometers southeast of Macclesfield.
The creek was given a poor rating because the site sampled showed evidence of major changes in ecosystem structure and moderate changes to the way the ecosystem functions. There was considerable evidence of human disturbance, including nutrient enrichment and weeds dominating the understorey vegetation on the banks but the stream still provided habitat for some rare and sensitive macroinvertebrate species.
A sparse community of at least 5 species of macroinvertebrates was collected from isolated, drying pools, up to 3.6 metres wide and 45 centimetres deep in autumn; the creek was dry in spring 2015 apart from a tiny puddle that was too small to sample. The community in autumn was dominated by generalists and species tolerant to poor water quality such as mosquitoes (Aedes) and beetles (Copelatus) and included small numbers of hydrophilid beetles, biting midges and snails (Glyptophysa). No rare, sensitive or habitat specialist species were collected or seen.
The water was slightly saline (salinity was 3,655 mg/L), moderately well oxygenated (56% saturated), clear, and with high concentrations of nutrients such as nitrogen (0.81 mg/L) and phosphorus (0.034 mg/L).
The sediments were dominated by living and dead detritus, with smaller amounts of bedrock, boulder, cobble, filamentous algae, sand and silt. Samples taken from below the surface were grey in colour and showed no evidence that the sediments were anaerobic or lacked oxygen.
Filamentous algae (mostly Spirogyra) covered about 10% of the channel and a number of submerged (Callitriche) and emergent plants (Cyperus, Juncus, Triglochin, Baumea and introduced Rorippa) covered 35% of the creek in autumn. In contrast, no plants were recorded within the channel in spring. The riparian zone was dominated by introduced grasses and woody weeds (eg gorse) under a canopy of gums and wattles lining the creek. The surrounding vegetation at the site was cleared grazing land with a few scattered gum trees.
Special environmental values
None detected in 2015.
Pressures and 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.
In addition, this site is located in an area where the total demand for water is higher than the sustainable limits set out in the water allocation plan. Natural Resources SA Murray–Darling Basin is monitoring the situation and will work with the community to develop solutions for managing high water demand where required.
|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.