SA Arid Lands Landscape Regional Summary
2022 Aquatic Ecosystem Condition Report
A total of 22 sites were sampled from the region during spring and early summer 2022, comprising 4 streams that flow into the Kati Thanda-Lake Eyre Basin and 18 from the mid to upper Flinders Ranges. Land use was dominated by agriculture (sheep and cattle grazing in the Flinders Ranges and cattle grazing in the Kati Thanda-Lake Eyre Basin) and nature conservation, with smaller catchment areas used for mining, roads, rural living and tourism.
- Of 22 sites sampled, 73% were in Good condition and the remaining 27% were in Fair condition.
- Climatic patterns leading up to and during sampling were consistent with other parts of South Australia in 2022, with both the Kati Thanda-Lake Eyre Basin and Flinders Ranges receiving above average rainfall and with average to below average maximum temperatures recorded.
- The better sites were mostly located in the gorges and upper reaches of streams in the Flinders Ranges and the four sites sampled from the larger creeks in the Kati Thanda-Lake Eyre Basin (LEB) were also rated in Good condition. These stream sites had a rich range of macroinvertebrates, intact native vegetation, and generally showed little to no damage caused by stock or feral animals grazing near each site.
- The sites in Fair condition were mostly lowland streams from the Flinders Ranges which included Mount Chambers, Baratta, Kanyaka, Pekina creeks, and two sites from Willochra Creek. These sites were dominated by a more generalist and tolerant range of macroinvertebrates, were more enriched with nutrients, and often showed evidence of fine siltation. The Willochra sites were also characterised by very high salinity.
- Most streams showed some evidence of slight to moderate nutrient enrichment but unlike sites sampled in 2017, few showed evidence of large numbers of feral goats or stock accessing riparian habitats and damaging stream banks.
- Macroinvertebrate communities were dominated by generalist and tolerant species with most of the rare and sensitive species found from flowing water habitats in freshwater streams (eg Brachina, Parachilna and Hookina creeks in the Flinders, and Cooper Creek in the Kati Thanda-Lake Eyre Basin.
- The only practical management options for the region are to continue efforts to reduce the build-up of feral animals (particularly goats in the Flinders Ranges) and to consider installing alternative watering points to reduce grazing pressure from animals concentrating around significant waterholes and springs. In some cases installing stock and animal exclusion fencing to protect particularly important sites may also be warranted but this would need to be assessed against the practicalities of constructing and maintaining fencing over at least 10-20+ years, and being able to demonstrate that positive environmental responses resulted from such a management response.
All sites sampled were assigned to either the Good (73%) or Fair (27%) rating due to the dominance of similar generalist aquatic macroinvertebrate communities (eg diverse range of beetles, waterbugs, dipterans and odonates) and presence of natural overstorey vegetation associated with each stream. The better sites showed only minor changes to animal and plant life, and some changes to the way the ecosystems functioned. These sites had a richer range of macroinvertebrates and usually supported at least a few rare, sensitive or habitat specialist species. The Fair sites showed moderate changes to animal and plant life, and some changes to the way the ecosystems functioned. They were dominated by a more generalist and tolerant range of macroinvertebrates and showed evidence of moderate nutrient enrichment, siltation and in some cases salinization effects.
No sites were in Very Good condition in 2022 as was the case in 2017, despite previous work in 2012 assigning this rating to six sites comprising four dry and two wet sites. The dry sites were rated highly due to the extent of habitat structure provided by the surrounding native riparian and surrounding vegetation, and lack of evidence of significant pressure from stock or feral animals visiting each waterway. The wet sites supported a wide range of regionally rare, sensitive and generalist species and comprised examples of the ‘best’ condition assemblages that are expected for streams in the Far North. None of these sites were resampled again in 2022, although the Oratunga Creek site was close to the previously sampled spring but showed evidence of too much nitrogen enrichment and too much fine sediment deposited in the creek to rate it any better than in Good condition.
The Good sites in 2022 were characterised by the dominance of naturally occurring vegetation throughout their catchments, a wide diversity of sediment types within each stream channel, and limited evidence of any significant damage caused by feral and stock animals accessing each site. They included 12 sites from the mid to northern Flinders Ranges (Artimore, Balcanoona, Eregunda, Spring, Aroona, Brachina, Tributary of Oratunga, Parachilna, Bunyeroo, Puttapa, Hookina and Frome creeks) and four streams (Lindsay, Neales, Cooper and Warburton creeks) draining into the Kati Thanda-Lake Eyre Basin.
The Fair sites included Mount Chambers and Baratta creeks from the mid-eastern part of the Flinders Ranges, and Pekina, Kanyaka and two Willochra creek sites from the southern Flinders Ranges. These included lowland and mid-gorge streams and generally had less effective riparian buffering vegetation and showed more significant nutrient enrichment than the better streams, possibly due to more regular damage caused by feral goat and stock animal grazing. Note that the Baratta Creek site was in better condition than in 2012, when it was assigned a Poor rating due to the more depauperate aquatic life present at that time, along with signs of gross nutrient enrichment and higher salinity. However, the Kanyaka Creek site was in poorer condition in 2022 than previous assessments that rated this stream site as Good when it supported several flow dependent species and 2 mayfly species.
It is important to note that a major assumption of the conceptual models developed for the Flinders Ranges and Kati Thanda-Lake Eyre Basin was that the high levels of nutrients (nitrogen and phosphorus) recorded from most streams in the region was sourced from human activities within each catchment, rather than from a natural source. This is consistent with the poor nutrient status attributed to most Australian soils (e.g. National Land & Water Resources Audit 2001). Consequently, it was assumed that historical and current stock grazing land uses, feral animal grazing, and in the case of Cooper Creek and Diamantina River, cropping and grazing practices further upstream in Queensland, have contributed towards the high nutrient concentrations and enrichment effects seen in many streams across the region.
The aquatic macroinvertebrate communities of streams in the region were typically dominated by a range of generalist and tolerant species, with the better sites generally providing suitable habitats (often flowing riffles) for several rare and sensitive species. Flinders Ranges streams were generally dominated by:
- waterbugs (Micronecta, Microvelia, Enithares and Anisops)
- dytiscid beetles (Allodessus, Platynectes, Necterosoma, Sternopriscus, Hyphydrus and Eretes)
- chironomids (Procladius, Paramerina, Larsia, Tanytarsus and Chironomus)
- mites (Arrenurus, Limnesiidae and Unionicolidae)
- hydrophilid beetles (Enochrus, Berosus and Limnoxenus)
- mosquitoes (Anopheles and Culex)
- biting midges (Bezzia and Nilobezzia)
- mayflies (Tasmanocoenis tillyardi and Cloeon)
- odonates (Coenagrionidae, Diplacodes, Hemianax and Hemicordulia)
- caddisflies (Triplectides australis and Hellyethira simplex).
A number of rare and uncommon macroinvertebrates were also recorded from the better rated sites, including a regionally endemic amphiphod (Brachina invasa) from Brachina Creek, leptophlebiid mayfly (Thraulophlebia inconspicua) from Spring Creek, and hydrobiosid caddisflies from flowing habitats in Parachilna and Hookina creeks. Despite high rainfall events falling prior to sampling, flow-dependent blackfly larvae (Simulium) and hydropsychid caddisflies (Cheumatopsyche) were uncommonly collected in 2022 from flowing habitats (riffles and trickles) in Eregunda, Hookina, Brachina and Parachilna creeks. Consequently, high rainfall (see below) did not result in more extensive areas of flowing riffle habitats being established that were capable of being colonised by these insects beyond their normal range.
Streams from the Kati Thanda-Lake Eyre Basin were generally dominated by low to moderate numbers of:
- mites (Unionicolidae)
- prawns (Macrobrachium)
- yabbies (Cherax)
- beetles (Hyphydrus, Necterosoma and Sternopriscus)
- biting midges (Bezzia and Nilobezzia)
- chironomids (Procladius, Larsia, Nanocladius, Cladotanytarsus, Tanytarsus, Cricotopus and Polypedilum)
- waterbugs (Micronecta and Anisops)
- mayflies (Tasmanocoenis arcuata)
- odonates (Orthetrum and Hemicordulia)
- caddisflies (Hellyethira simplex, Ecnomus pansus, Triplectides and Oecetis).
A number of rare and uncommonly collected macroinvertebrates were recorded including a chironomid (Coelopynia) and mayfly (Cloeon) from Lindsay Creek, snails (Centrapala and Thiara), mussel (Corbiculina), limpet (Ferrissia), caenid mayfly (Wundacaenis) and odonate (Austrogomphus) from Cooper Creek, and a caddisfly (Ecnomus continentalis) and Centrapala from Neales Creek. Mussel shells from the family Hyriidae (Velesunio) were also noted from the Cooper Creek at Cullyamurra. Unlike 2017 when no flow-dependent species were recorded, the region normally supports a few species (see Madden et al. 2002) such as simuliids (Simulium) and a dytiscid beetle (Platynectes) that were both collected from the Cooper and Warburton creek sites in 2022.
Most streams in the region had limited riparian habitats (5-10m wide in places), which is probably largely due to the arid climate that dominates much of the Flinders Ranges and Kati Thanda-Lake Eyre Basin. The vegetation along the majority of creeks and rivers comprises a single line of gum trees (mostly River Red Gums, with Coolabah trees dominating among parts of the Eastern Kati Thanda-Lake Eyre Basin) over a sparse understorey of rushes, sedges, chenopods, introduced grasses and weeds that graded into natural surrounding vegetation dominated by gums and wattles. The exception was where streams passed through conservation parks and the understorey plants were mostly native species with only a few weeds. The more permanent streams generally supported submerged (eg Chara, Potamogeton, Ruppia in Flinders streams only) and emergent plants within their channels (eg Typha in Flinders, Persicaria in Eastern Kati Thanda-Lake Eyre Basin) and on the banks (eg sedges Cyperus and rushes Juncus). The more temporary streams in the Flinders Ranges that were starting to dry and the streams in the Western Kati Thanda-Lake Eyre Basin either lacked aquatic plants or only had a few scattered sedges and rushes on the banks.
Finally, the sampling results from spring 2022 were probably influenced in part due to the wetter than average rainfall and average to below average maximum temperatures that occurred in both the Kati Thanda-Lake Eyre Basin and Flinders Ranges in the months leading up to and sampling in each region. For example, Moomba airport (station 017123) recorded its wettest July rainfall on record, and received double (21 mm) its average September rainfall when samples were taken. And Hawker (station 019017) received 110 mm rainfall in October when its average was 25 mm, and during November received 35 mm when the average was about 20 mm. Consequently, both regions were sampled during favourable conditions for streams in the region, representing ideal wetted habitats for aquatic invertebrates and plants to thrive in each region.
Special environmental features
The most notable aquatic macroinvertebrates recorded in 2022 included the following:
- Restricted Flinders Ranges endemic crustacean Brachina invasa from Brachina Creek;
- Restricted LEB endemic mayfly Wundacaenis from Cooper Creek.
- Restricted LEB endemic snails Centrapala and Thiara from Cooper Creek and Centrapala from Neales Creek (both species are presumed extinct in the lower River Murray (Walker et al 2018).
A large number of rare, sensitive, opportunistic, generalist and tolerant species of macroinvertebrates were found in 2022, including commonly occurring flow-dependent species (e.g. blackfly Simulium and caddisfly Cheumatopsyche) from riffle habitats in a small number of flowing streams in the Flinders Ranges. The better streams generally included some regionally significant species and a richer assemblage of mites, beetles and dipterans whereas the poorer streams lacked suitable habitat and had poorer water quality (more saline or nutrient enriched) and supported a less diverse assemblage of tolerant and generalist insect species.
The results from previous sampling studies that describe similar and additional species from the region can be found from the following publications: Flinders Ranges macroinvertebrates (Boulton & Williams 1996; Goonan & Schulze 2001) and fish (Pierce et al. 2001), and Kati Thanda-Lake Eyre Basin macroinvertebrates (Sheldon & Puckridge 1998; Madden et al, 2002; Marshall et al. 2006) and fish (Schmarr et al. 2015).
Pressures and management responses
Livestock have direct access at some sites and upstream in the catchments, exerting excessive grazing pressure on vegetation, causing bank erosion and addeding nutrients to the watercourses.
The SA Arid Lands Landscape Board recognises that both direct and diffuse impacts on aquatic ecosystem condition can occur through direct stock access and excessive grazing pressure from stock and feral herbivores. Technical advice and incentives are offered to land managers in the region, as funding permits, to address these impacts as part of promoting pastoral sustainability in the region. The Board’s Regional Plan also has Water Management and Sustainable Land Management as key priorities for the region, which guide the activities that aim to reduce pressures to freshwater systems in the region.
Highly saline soils in the catchment.
The SA Arid Lands Landscape Board promotes best practice soil management works from the region that aim to improve soil moisture and perennial vegetation on farming land, including those affected by salt scalds.
Feral goats and other pests (eg rabbits, camels, donkeys, pigs) are exerting excessive grazing pressure on vegetation in some areas, causing erosion and adding excessive nutrients to some watercourses.
|The SA Arid Lands Landscape Board staff work closely with land managers to identify and manage pest animals and plants they may encounter in their properties. The Board has also been successful in receiving funding for projects addressing the management of pest animals, while they periodically undertake targeted culls. For up to date information about the range of activities occurring in the region, follow the Board’s quarterly newsletter.|
Boulton AJ & WD Williams 1996, 'Aquatic Biology', in Natural History of the Flinders Ranges (ed.s M Davies CR Twidale & MJ Tyler), Royal Society of South Australia, Adelaide, pp 102-112.
Goonan P & D Schulze 2001, 'River health in the Flinders Ranges based on aquatic macro-invertebrates as biological indicators' in A Biological Survey of the Flinders Ranges, South Australia 1997-1999 (ed. R Brandle), Biodiversity Survey and Monitoring, National Parks and Wildlife, South Australia, Department for Environment and Heritage, pp 16-24.
Madden CP, McEvoy PK, Taylor DJ, Tsymba, V, Venus TA & PM Goonan 2002, 'Macroinvertebrates of watercourses in the Lake Eyre Basin, South Australia', Verhandlungen des. Internationalen Verein, Limnologie 28: 591-600.
Marshall JC, Sheldon F, Thoms M & S Choy 2006, 'The macroinvertebrate fauna of an Australian dryland river: spatial and temporal patterns and environmental relationships', Marine and Freshwater Research 57: 61-74.
National Land & Water Resources Audit 2001, Nutrient balance in regional farming systems and soil nutrient status, Final report NLWRA, September 2001.
Pierce BE, Young M & T Sim 2001, 'Flinders Ranges fishes', in A Biological Survey of the Flinders Ranges, South Australia 1997-1999, (ed. R Brandle). Biodiversity Survey and Monitoring, National Parks and Wildlife, South Australia, Department for Environment and Heritage, pp 25-33.
Schmarr DW, Cheshire DLM, Mathwin R, McNeil DG, Howson T, Cockayne B & A Duguid 2015, Evidence based approaches to condition assessment of fish communities in the Lake Eyre Basin, Central Australia, Goyder Institute for Water Research Technical Report Series No. 15/45, Adelaide, South Australia.
Sheldon F & JT Puckridge 1998, 'Macroinvertebrate assemblages of Goyder Lagoon, Diamantina River, South Australia', Transactions of the Royal Society of South Australia 122: 17-31.
Walker KF, Corbin TA, Cummings CR, Geddes MC, Goonan PM, Kokkin MJ, Lester RE, Madden CP, McEvoy PK, Whiterod N & S Zukowski 2018,'Chapter 3.5 Freshwater Macro-Invertebrates' in Natural History of the Coorong, Lower Lakes, and Murray Mouth Region (Yarluwar-Ruwe), (eds L Mosley, Q Ye, S Shepherd, S Hemming & R Fitzpatrick), Royal Society of SA, Adelaide.