SA Murray–Darling Basin NRM Regional Summary
2010 Aquatic Ecosystem Condition Report
A total of 43 sites were sampled in the eastern Mount Lofty Ranges in autumn and spring 2010. These sites were located throughout the region between Burra Creek in the north and Currency Creek in the south. Rainfall patterns are dominated by winter rains and annual averages range from over 700 mm in the eastern hills and southern areas (e.g. Mount Barker, Kuitpo Forest, Mount Compass) to less than 300 mm on the plains near the River Murray (eg Black Hill).
Land use is dominated by agriculture (grazing and dryland cropping) and also includes areas of irrigated vines and orchards, dairying, forests, urban areas, mines and remnant native vegetation. The generally low hills and flat plains of the Mount Lofty Ranges have been extensively cleared since European settlement, with only about 15% of the original vegetation remaining (EPA 2008). The Eastern Mount Lofty Ranges has, however, been particularly altered because only about 8% of the original pre-European vegetation (eg grassland and grassy woodland communities) remains (O’Connor et al 2008).
- The streams monitored extended from Burra in the north to Goolwa in the south. They included streams that drain to the River Murray (eg Burra and Reedy creeks), or discharge to groundwater in the Murray plains (eg Truro and Salt creeks) or others that drain into the Lower Lakes region (eg Finniss and Bremer Rivers).
- No site was assessed in either an Excellent or Very Poor condition whereas 1, 5, 23 and 14 sites were assessed in Very Good, Good, Fair and Poor condition, respectively.
- The better sites were from the Finniss River catchment on the Fleurieu Peninsula and the poorer sites were from the more ephemeral or saline streams, or downstream from wastewater discharges.
- Many rare and sensitive aquatic species occur in the region, particularly from the Finniss River catchment.
- Most streams were affected by nutrient enrichment.
- Riparian zones were often reduced and degraded due to the lack of trees and shrubs and dominance by introduced weeds.
Sites monitored in the eastern Mount Lofty Ranges during 2010 were considered to be in Very Good to Poor condition. No sites were assigned to either the Execellent or Very Poor condition classes. Of the sites assessed, one (2%) was considered to be in Very Good condition with very little change to animal and plant life; five (12%) were considered to be in Good condition with only minor changes to animal and plant life; 23 (53%) were considered to be in Fair condition, with moderate changes to animal and plant life, and some changes to the way the ecosystems functioned; and 14 (33%) were considered to be in Poor condition, with evidence of major changes in the animal and plant life, and moderate changes to the way the ecosystems functioned.
The site in Very Good condition was in Tookayerta Creek near Mount Compass and was characterised by a high diversity of aquatic fauna and presence of many rare and sensitive species. However, much of the catchment upstream is used for grazing which could potentially increase nutrient and sediment loads to this creek in the future.
The five sites assessed in a Good condition included Tookayerta Creek near Tooperang, Finniss River near Yundi, Finniss River near Mount Observation, Blackfellows Creek near Mount Magnificent Conservation Park and Bull Creek near Ashbourne. These sites were all located within the Finniss River catchment on the Fleurieu Peninsula. They all retain a high diversity of aquatic species and include some rare species but show signs of bank erosion and degraded vegetation within the riparian zone.
The sites assessed in Fair and Poor conditions were from streams in agricultural settings that had moderately diverse to sparse aquatic communities, evidence of obvious nutrient enrichment and degraded riparian zones. The worst sites sampled included ephemeral or saline streams (eg lower Marne River, Rodwell and Paris creeks), a dry site (Baldina Creek) or downstream from a discharge of treated effluent (Mount Barker Creek)
Most sites showed evidence of nutrient enrichment by the presence of large growths of filamentous algae, phytoplankton, reeds or other aquatic plants, or high concentrations of nitrogen and phosphorus in the water. Many streams sampled had significantly disturbed riparian zones with cropping or other introduced grasses and weeds often being the main plants growing on the banks. Agricultural runoff carrying nutrients and sediment, and bank erosion from stock damage were considered to be significant stressors affecting the condition of streams in the region. Saline groundwater discharges into and forms the baseflow for many streams in the drier parts of the region on the Murray plains, and contributes to the generally poorer condition of the lower Marne River, Logan, Mitchell Gully and Salt creeks.
The aquatic macroinvertebrate communities of most streams were typically dominated by a range of tolerant species that included an amphipod crustacean (Austrochiltonia australis), small unidentified chironomids, an introduced snail (Physa), waterbugs (Micronecta, Microvelia and Anisops) and a caddisfly (Triplectides). Sites with flowing water also provided habitat for large numbers of blackfly larvae (Simulium ornatipes) and psychodid caddisflies (Cheumatopsyche). Worms and various chironomids (eg Chironomus, Dicrotendipes and Cricotopus) were also often collected in low numbers from most sites.
Special environmental features
Many rare and sensitive species were found in the region in 2010. One very rare and restricted macroinvertebrate species, a mayfly (Tasmanophlebia), was found at two sites on Tookayerta Creek. This mayfly only occurs in permanently flowing, sandy, freshwater streams from the Fleurieu Peninsula in South Australia.
Other rare, sensitive or uncommon species collected included various beetles (Laccophilus sharpi and Limbodessus), a mite (Diplodontus), damselfly (Nososticta solida), stoneflies (Dinotoperla evansi, Riekoperla naso, Illiesoperla mayi, Austrocerca tasmanica and Leptoperla tasmanica), mayflies (Offadens, Koorrnonga inconspicua, Atalophlebia australasica and Atalophlebia australis), caddisflies (Taschorema, Ulmerochorema, Ethochorema hesperium, Orthotrichia bishopi, Atriplectides dubius, Notalina fulva, Lingora, Triplectides similis and Triplectides volda), a blackfly (Paracnephia), chironomid (Eukiefferiella) and waterbug (Hydrometra).
The only threatened species of fish recorded during the 2010 surveys were the Mountain Galaxias (Galaxias olidus) and Climbing Galaxias (Galaxias brevipinnis) from four sites in the Finniss River catchment that were each assigned a good condition rating (eg Finniss River at Yundi and near Mount Observation, Blackfellows and Bull creeks).
Previous sampling of streams from the eastern Mount Lofty Ranges since the mid 1990s, has included other rare and uncommon species that were not recorded in 2010. They included: a mite (Rhynchaustrobates bandus); beetles (Sclerocyphon and Simsonia); mayflies (Centoptilium elongatum and Nousia fuscula); stonefly (Newmanoperla thoreyi); caddisflies (Apsilochorema, Maydenoptila rupina, Hydroptila calcara, Hydroptila losida, Hydroptila scamandra, Oxyethira columba and Triaenodes); chironomids (Podonomopsis, Podonomus, Aphroteniella, Coelopynia pruinosa, Rheocricotopus, Gymnometriocnemus, Stempellina and Xenochironomus); dragonflies (Austrogomphus australis and Austogomphus guerini); lacewing (Austroneurorthus); subterranean crustacean from the Family Parabathynellidae; and freshwater crab (Amarinus lacustris) which is more commonly found in the River Murray channel and coastal lakes in the South East.
Other threatened native fish species collected from the region in the past include the Yarra Pygmy Perch (Nannoperca obscura), Southern Pygmy Perch (Nannoperca australis) and the River Blackfish (Gadopsis marmoratus) (M. Hammer, Aquasave Consultants, personal communication 2009).
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).||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 some creeks, 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 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 in some creeks resulting from water extraction and climate variability (reducing ecological integrity.||
For creeks located in the eastern Mount Lofty Ranges, 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.
For creeks located in the Marne Saunders catchment, a Water Allocation Plan and licensing system has been developed.
For those sites not included in a Water Allocation Plan, the Board’s Regional NRM Plan sets limits for new dam construction through the water affecting activity permits section. The dam capacity limits aim to keep new dam development within sustainable limits.
|Widespread introduced trees and weeds in riparian zones (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. 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.|
|Saline groundwater inflows to some creeks (reducing ecological integrity).||Saline groundwater inflows may be exacerbated by two things; vegetation clearing and resultant increase in rainfall recharge, or the extraction of surface water reducing the dilution factor in natural saline discharge zones. The SA Murray–Darling Basin NRM Board’s Land Management Program strategically invests in salinity ‘hotspots’ by providing incentives to land managers to plant perennial pasture/fodder crops or revegetation to reduce recharge. The NRM Board works with various agencies to minimise any further vegetation clearing which may impact on the catchment’s water balance. The NRM Board seeks to manage and provide for environmental flows to allow natural dilution of saline waters through the development of Water Allocation Plans and Water Affecting Activity policies across the region.|
|Stormwater runoff from some urban areas causing high water velocities, containing nutrients and sediments (causing habitat disturbance, algal growth and aquatic weeds).||The SA Murray–Darling Basin NRM Board is working closely with local government through various projects including: Strengthening Basin Communities, funded under the Water for the Future Program to develop Integrated Water Management Plans; the implementation of Water Sensitive Urban Design principles in development planning and conditions; encouraging the implementation of Best Practice Stormwater Management Guidelines. The NRM Board also administers the statutory requirements of the NRM Act relating to Water Affecting Activities.|
|Large nutrient inputs from numerous diffuse sources in some catchments (leading to extensive growth of algae and aquatic weeds).||The SA Murray–Darling Basin NRM Board’s Land Management Program provides free technical advice and education to land managers to minimise fertiliser, manure, or effluent sources of nutrients. The NRM Board also works closely with local government and developers to pursue industry best practice and manage sediment loads entering waterways. The water Allocation Planning and Water Affecting Activities policies of the NRM Board also seek to minimise nutrient inputs and allow for natural flows to dilute naturally occurring nutrient loads in waterways.|
|Extensive aquatic weed growth in some creeks (reducing ecological integrity).||The SA Murray–Darling Basin NRM Board provides free technical advice and community education to assist land managers in dealing with the integrated management of aquatic weeds. The 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.|
|Wastewater discharges to some creeks, adding excessive nutrients and organic matter (leading to algal growth and aquatic weeds).||
Mount Barker Community Wastewater Management System
Plans are being developed by the District Council of Mount Barker to minimise the discharge from the Community Wastewater Management System by significantly increasing reuse opportunities.
Bird in Hand Wastewater Treatment Plant
SA Water assess and undertake scheduled process improvement actions at the wastewater treatment plant, with the aim to reduce environmental risk and ensure operations are compliant with EPA licence conditions.
The SA Murray–Darling Basin NRM Board works with local government, SA Water and other agencies to encourage the development of reclaimed water for more appropriate uses.
|Feral predatory fish in some creeks (trout and redfin) (reducing ecological integrity).||Local volunteer groups are undertaking works at some sites. The SA Murray–Darling Basin NRM Board opportunistically removes pest fish during monitoring activities. Other agencies are responsible for the control of pest fish and have undertaken some awareness-raising activities throughout the region.|
- Download the brochure for creeks and lakes
- Download panel assessment information sheet
- O’Connor P, A Morgan & A Bond 2008, Bushbids: Biodiversity Stewardship in the Eastern Mount Lofty Ranges, South Australia, Australian Government and South Australian Murray-Darling Basin Natural Resources Management Board.
- Environment Protection Authority 2008, The State of Our Environment, South Australia, 2008, Environment Protection Authority, South Australia.