Paralana Creek, Paralana Hot Springs
2012 Aquatic Ecosystem Condition Report
- Permanent flowing stream in autumn but unable to resample in spring due to poor condition of the access road
- Moderately diverse macroinvertebrate community with a few rare, sensitive and flow-dependent species present
- Water was moderately fresh, clear and moderately high in nutrients
- Riparian vegetation consisted of native trees and shrubs and the spring was covered by filamentous algae and a few aquatic plants
About the location
Paralana Creek rises near Freeling Heights in the Arkaroola Protection Area and flows south-east for about 45 km, where it eventually discharges onto the plains surrounding the north-western edge of Lake Frome; flow only extends onto the plains during exceptionally wet years. The only land use in the 2,521 hectare catchment, upstream from the site sampled, was grazing natural vegetation, although grazing not been actively carried out on the pastoral property for over 30 years. The monitoring site was located at the hot springs on Paralana track, about 18 km north-north-east from Arkaroola.
The creek was given a Good rating because the site sampled showed evidence of relatively minor changes in ecosystem structure and function. There was evidence of human disturbance including nutrient enrichment and weedy riparian zones but the stream provides habitat for a few rare, sensitive and flow-dependent species of macroinvertebrates and at least two aquatic plants.
A moderately diverse community of at least 24 species of macroinvertebrates was collected from the creek, 1-2.1 m wide and up to 15 cm deep, in autumn 2012; the site was inaccessible in spring due to the poor condition of the track to the springs. The creek consisted of shallow, non-flowing pools connected by smaller areas of fast-flowing riffle habitats. The community was dominated by moderate numbers of mosquitoes (Anopheles) from the pool habitats and chironomids from the riffles. Other species collected in much smaller numbers included worms, beetles (Allodessus, Necterosoma, Paranacaena and Paracymus), biting midges (Forcipomyia and Bezzia), chironomids (Procladius, Paramerina, Larsia, Tanytarsus, Paratanytarsus, Rheotanytarsus, Chironomus and Harnischia), tipulid flies, mayflies (Cloeon), waterbugs (Anisops), odonates (Hemianax, Diplacodes, Orthetrum and gomphids) and caddisflies (Triplectides australis). The only rare and/or sensitive species collected were the chironomid Harnischia and the baetid mayfly; the latter is one of two widely distributed mayflies that frequent permanent freshwater streams in the region. At least two species of chironomids that commonly occur in flowing water were collected (Rheotanytarsus and Harnischia) but a wider range of flow-dependent species that typically occur in the region were absent (e.g. blackfly larvae, beetle Platynectes and caddisfly Cheumatopsyche). The site also lacked any mites, molluscs or crustaceans which may be an indication that the springs may lack sufficient habitat complexity or be too ephemeral to sustain a wider range of species, rather than issues related to the radioactive baseflow, since similar patterns were seen at several other Flinders Ranges streams in 2012.
The water was moderately fresh (salinity 1,314 mg/L), well oxygenated (134% saturation), clear, and with moderate to high concentrations of nutrients such as phosphorus (0.04 mg/L) and nitrogen (0.94 mg/L). The discharge of hot groundwater to the springs was evident because the water temperature was 27Â°C in May, compared to other sites from the region that were typically less than 15Â°C.
The sediments were dominated by filamentous algae, gravel and detritus with smaller amounts of cobble also present; samples taken from below the surface were grey and blackened sands that were sulphidic, indicating that the sediments were anaerobic, or lacking in oxygen. No evidence of any significant bank erosion was noted and the only animal faeces recorded from the edges of the waterhole were from kangaroos.
A moderate amount of phytoplankton was present (chlorophyll a 8.8 Âµg/L) and over 65% of the shallow margins of the creek was covered by a filamentous alga (Spirogyra). About 10% of the creek was covered by two species of aquatic plants (sedge Cyperus gymnocaulos and cumbungi Typha). The riparian vegetation was dominated by River Red Gums and acacias over native shrubs, sedges, rushes, weeds and other understorey species on the moderately well vegetated banks (50-79% vegetative cover). The surrounding vegetation at the site comprised low native woodland dominated by eucalypts, wattles and paperbarks.
Special environmental features
Paralana Creek is a largely natural, permanent stream in the Northern Flinders Ranges that provides habitat for a moderately diverse range of aquatic insects and worms, which also includes a few rare, sensitive and flow dependent macroinvertebrates. Few human disturbances are evident due to limited access to the catchment and the removal of sheep from the pastoral leases during the 1970’s. The site sampled is one of the most significant hot springs in the region, a factor that continues to attract tourist interest to visitors to the Arkaroola area. The Paralana Hot Springs also has a high cultural significance because the Aboriginal people knew the site as Vadaardlanha and describe the way the hot spring was created in the story Tjukurrpa.
Pressures and management responses
|Feral goats and donkeys are exerting excessive grazing pressure on vegetation, causing erosion and adding excessive nutrients to the watercourse.
|The SA Arid Lands Natural Resources Management Board provides technical advice and incentives for the management of introduced weeds and feral pest animals, as funding permits. Pest management efforts are guided by a region-wide strategy, based on risk assessment, to determine priority locations and species. Funding is actively sought from a number of sources to support region-wide integrated management.