Marcollat Watercourse at Jip Jip Waterhole, near Jip Jip Conservation Park
2014 Aquatic Ecosystem Condition Report
- Permanently wet with isolated pool habitats in autumn and spring 2014
- Moderately diverse macroinvertebrate community with no rare or sensitive species
- Obvious signs of gross nutrient enrichment
- Riparian vegetation extensive with native gums and paperbarks over rushes and introduced grasses
About the location
The Marcollat Watercourse at Jip Jip Waterhole is located towards the northern end of the watercourse in the lower South East, and includes a catchment area of more than 2000 square kilometres. It comprises a series of largely connected wetlands in the inter-dunal flat between Harper Range and Stewart Range.
The Marcollat Watercourse is part of an artificially constructed drain network where the primary function is to remove surface water and draining saline groundwater to improve agricultural productivity in the region (Department for Water 2010). Given its artificial character, the watercourse is not expected to be in a highly rated aquatic ecosystem condition, although it does provide significant habitat for many aquatic species in the region.
The major land uses are grazing and native vegetation. The monitoring site was located at the waterhole, about 300 metres east of Ballater Road and around 36 kilometres north-west from Padthaway.
The watercourse 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 poor in-stream habitat.
A moderately diverse community of about 23 species of macroinvertebrates (15 in autumn and 19 in spring) was collected and/or seen from isolated pool habitats, up to 15 metres wide and over 70 centimetres deep, in autumn and spring 2014. The community was dominated by moderate to large numbers of generalists and species tolerant to poor water quality, including amphipods (Austrochiltonia), dytiscid beetles (Necterosoma), chironomids (Chironomus, Dicrotendipes and Polypedilum), waterbugs (Micronecta) and caddisflies (Triplectides australis and Ecnomus turgidus). It also included smaller numbers of introduced (Physiella) and native snails (Glyptophysa), springtails, baetid mayflies (Cloeon), several other beetles and waterbugs, soldierflies and damselflies. Skin casts from yabbies were also seen in spring, indicating that they also occurred in the pools at the site. No rare or sensitive species were recorded, although the caddisfly (E, turgidus) is an uncommonly collected species for the region. This assemblage of snails, crustaceans and insect groups represents an unremarkable assemblage of species that are often collected from ephemeral habitats in the State.
Hundreds of tortoises were seen during both surveys and the only fish observed at the site were a few introduced mosquitofish (Gambusia) in autumn.
The water was moderately fresh (salinity ranged from 1,225-1,942 mg/L), well oxygenated (70-84% saturation), clear and strongly coloured when the water level was low in spring, and with high concentrations of nutrients such as nitrogen (4.22-4.54 mg/L) and phosphorus (0.55-1.11 mg/L).
The sediments were dominated by detritus and sand, with smaller amounts of silt, clay, boulder and gravel also present; samples taken from below the surface comprised slightly black rocks and grey sands that released sulfide when tested, which indicates that the sediments were anaerobic and lacked oxygen. No evidence of any bank erosion was noted and the only animal droppings seen in the vicinity of the watercourse were from kangaroos; the waterhole was fenced to prevent stock access.
A large phytoplankton bloom was recorded in autumn (chlorophyll a ranged from 48-303 Âµg/L) but no significance growths of filamentous algae were seen in 2014. Less than 10% of the pool surface were covered by a few rushes (Juncus) and the riparian zone was dominated by patches of gums and paperbarks over rushes and sedges (Baumea and Isolepis).
The surrounding vegetation at the site was native woodland, consisting of gums, wattles and paperbark trees over introduced grasses.
Special environmental features
None detected apart from the large extent of native vegetation surrounding the watercourse at the site sampled.
Pressures and management responses
|Livestock having direct access (causing sediment erosion and adding excessive nutrients).||Drains have been constructed since the 1860s as an engineering solution to support agricultural development and it is South Eastern Water Conservation and Drainage Board practice to lease drain reserves for grazing in certain circumstances. Not all drains are subject to grazing and leases for grazing are only approved following an engineering and environmental assessment. Lease conditions require the lessee to fulfil pest plant, pest animal and CFS management requirements, thereby relieving the Board of these responsibilities.|
|Limited riparian zone vegetation (reducing habitat quality, increasing sediment erosion).||The South Eastern Water Conservation and Drainage Board has undertaken a limited revegetation program at key locations, and has the ability to undertake further revegetation works when resources allow. Revegetation at biological hotspots is recognised as a mechanism to reduce nutrient input and soil erosion, and can be undertaken if it does not impede access for management and maintenance.|