Riparian vegetation consists of mostly introduced species with vineyards and cropping beyond
Area map
About the location
The North Para River is one of the largest streams in the Northern Mount Lofty Ranges. It rises at an elevation of about 450 m in the Flaxman Valley near Eden Valley and flows north towards Angaston, where the river flows south-east through Nuriootpa, Tanunda and Rosedale before eventually joining with the South Para River at Gawler to form the Gawler River. The major land uses in the 44,040 hectare catchment were stock grazing, irrigated vines and cropping, with smaller areas used for other minimal uses, roads, dams, residential living and mines. The site was located in the lower reaches just upstream from the weir near Chateau Yaldara Winery off Henschke Road, about 3 km north from Lyndoch.
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 and the presence of weeds in the riparian zones but the stream still provided habitat for some rare and sensitive macroinvertebrate species.
Findings
A highly diverse community of at least 56 species of macroinvertebrates was collected from this flowing creek, approximately 6 m wide and more than 1 m deep, in autumn and spring 2015. The creek consisted of slow-flowing pools with fast-flowing riffle sections between the pools in both autumn and spring 2015. The site was dominated by Hydrobiidae snails, worms, blackfly larvae and midge larvae. Other species collected in smaller numbers included a range of generalist and pollution tolerant species, such as flatworms, snails, round worms, mites, scuds, freshwater shrimp, eight different beetles, a diverse range of non-biting midges, mayflies, waterbugs, damselflies and dragonflies and caddisflies. Some sensitive and rare species, as well as flow-dependent species, were also collected, including blackfly larvae (Simulium), stoneflies (Dinotoperla and Riekoperla), and the caddisflies Cheumatopsyche, Triplectides similis, and Notalina. Introduced fauna such as mosquitofish and the snails Potamopyrgus and Physiella were seen in the creek. There was also evidence of yabbies being present in the creek.
The water was brackish (salinity ranged from 2,087-2,397 mg/L), moderately well oxygenated (37-69% saturation) and clear, with moderate to high concentrations of nutrients such as nitrogen (0.72-0.81 mg/L) and phosphorus (0.037-0.099 mg/L). Small patches of oil were visible on the water’s edge and froth was also noticed.
The sediments were dominated by gravel, cobble, pebbles and silt in the riffle sections and detritus, algae and silt in the slow-flowing pools. Samples taken from below the surface were sandy grey and showed evidence of being anaerobic, or lacking oxygen during some months of the year. Only small deposits of silt covered the stream bed to a depth of about 1 cm in places and no significant areas of bank erosion were seen. There was obvious signs of stock access to the creek with sheep droppings seen on the banks.
A small amount of phytoplankton (chlorophyll a ranged from 1.97-2.58 µg/L), which included a moderate amount of cyanobacteria or blue-green algae (chlorophyll b 0.6 µg/L). Filamentous algae (Cladophora and Spirogyra) covered more than 10% of the site and more than 35% of site was covered by a range of aquatic plants, including the submerged plant Chara, and several emergent plants (Bolboschoenus,Cyperus, Juncus, Phragmites, Schoenoplectus, and Typha). The riparian zone consisted olive trees and scattered gums with an understorey of exotic grasses, onion weed and wild roses. The surrounding vegetation was used for cropping and vineyards.
Special environmental features
North Para River provides important habitat for many rare, sensitive or flow-dependent species such as blackfly larvae, stoneflies and caddisflies that are dependent on the near permanent flows that occur in this creek.
Pressures and management responses
Pressures
Management responses
Livestock having direct access at the site and upstream (causing sediment erosion and adding excessive nutrients).
The Adelaide and Mount Lofty Ranges NRM Board’s land management program encourages and promotes managing land to improve water quality. This includes incentives for waterway and wetland fencing to exclude or limit stock from entering riparian zones.
Widespread introduced weeds in the riparian zone at the site and upstream (reducing habitat quality).
The Adelaide and Mount Lofty Ranges NRM Board has several pest plant (weed) mitigation and control programs. They work closely with landholders to control weeds on their property and to help stop the spread to other properties and waterways.
This aquatic ecosystem condition report is based on monitoring data collected by the EPA. It was prepared with and co-funded by the Adelaide and Mount Lofty Ranges NRM Board.