The Inland water report assesses the state and trends of freshwater-related ecological processes and key species populations, with grades ranging from very poor with worsening trends across the Murray–Darling Basin, through poor to good condition with stable trends for south-eastern and south-western regions, to good grades for much of the rest of the country.

Despite being one of the world’s most arid countries, Australia’s aquatic environment supports a rich diversity and endemicity. Inland waters are characterised by high variability, which has shaped aquatic ecosystems. A significant number of plants and animals are dependent on these ecosystems during at least part of their lifecycle. Changes in land use and land management practices—such as changes in flow, water quality and the availability of habitat—can place significant pressures on aquatic environments. Freshwater and riparian ecosystems are also likely to be highly vulnerable to the effects of the current phase of rapid anthropogenic climate change because of their high levels of exposure and sensitivity to changes in climatic stimuli.

Jurisdictional reporting on freshwater species and ecosystems

Jurisdictions generally report the condition of aquatic ecosystems as poor to moderate, although availability of information is often described as poor or limited.

Australian Capital Territory

• Key trends:
  • Ecological condition of waterways in the Australian Capital Territory is generally poor, partly because sampling mostly occurs in areas that are heavily affected by urban or rural land use.
  • Since 2011, the number of sites monitored for ecological condition rated as severely or significantly impaired has declined, and the percentage of sites rated as similar to minimally disturbed reference areas has increased from 24 per cent to 34 per cent.
• Assessment grade and adequacy of information:
  • Ecological condition: grade—poor; trend—improving; confidence in grade and trend—good.

New South Wales

• Key trends:
  • The overall condition of rivers across New South Wales is moderate. Riverine aquatic ecosystems in the major rivers of the Murray–Darling Basin are generally in poorer condition than those in coastal rivers.
  • Fish communities are generally in poor condition across the state and continue to decline within the Murray–Darling Basin. The widespread distribution of introduced carp in the Murray–Darling Basin has had a significant impact on the health of fish communities.
  • Nine of the 28 native freshwater fish species found in the New South Wales portion of the Murray–Darling Basin are listed as threatened with extinction under the Fisheries Management Act 1994, and an additional 4 fish species have populations listed as endangered. Seven freshwater invertebrates are also listed as threatened species under the Act.
  • Freshwater fish surveys during the past 3 years found that
    • 8 per cent of all sites sampled were free from introduced fish, mainly in coastal rivers
    • 12.7 per cent of sites contained only introduced fish
    • introduced taxa accounted for 50 per cent of the fish species collected at each site, 52 per cent of total fish abundance and 72 per cent of total fish biomass, averaged across all sites

These numbers are higher than those reported in NSW SoE 2012

• Increased rain and flooding from 2010 to 2012 inundated many wetlands, increasing waterbird abundance and breeding activity. In 2013–14, the return to a drying climatic phase has seen a reduction in the extent of wetland inundated, and a decrease in waterbird abundance and breeding activities.
• Inland wetland vegetation communities that have received environmental watering have improved in condition since 2012. On-ground surveys at sites that received environmental water revealed that vegetation condition and waterbird diversity were maintained, with many of these wetlands acting as refuges for dependent species during the drying period.
• Assessment grade and adequacy of information:
  • Ecosystem health for the Murray–Darling Basin rivers: grade—poor; trend—stable; information availability—limited.
  • River condition for New South Wales rivers: grade—moderate; trend—unknown; information availability—limited.
  • Health of fish assemblages: grade—poor; trend—increasing impact; information availability—reasonable.
  • Nitrogen and phosphorus levels: grade—moderate; trend—decreasing impact; information availability—reasonable.
  • Wetland extent: grade—moderate; trend—stable; information availability—limited.
  • Wetland condition: grade—moderate; trend—stable; information availability—limited.
  • Waterbird abundance and diversity: grade—poor; trend—increasing impact; information availability—good.
  • Extent and condition of groundwater-dependent ecosystems: grade—unknown; trend—uncertain; information availability—limited.

Queensland

• Key trends:
  • Sediment, nutrients and chemicals, and the loss of riparian forests are the major catchment pressures that broadly affect Queensland’s freshwater rivers, but vary in their relative importance between regions.
  • More than 94 per cent of the pre-European settlement extent of freshwater wetlands in Queensland remained in 2013. Changes in the extent of freshwater wetlands have been monitored in Queensland since 2001. Wetland loss peaked at a rate of 0.12 per cent during 2001–05. The rate of freshwater wetland loss decreased to 0.04 per cent during 2005–09 and 0.03 per cent in 2009–13.
  • Of the 3 freshwater wetland systems—lacustrine, palustrine and riverine—the greatest ongoing losses have occurred in palustrine and riverine systems in the Murray–Darling and North East Coast drainage divisions.
  • Eight per cent per cent of freshwater wetlands in Queensland are within protected areas. The majority are palustrine systems and are within national parks.
  • Invasive non-native fauna species, particularly pest fish, are relatively widespread in some sections of Queensland’s freshwater ecosystems, and have the potential to degrade and modify aquatic environments, and displace native species.
  • Invasive non-native flora species can have significant impacts on freshwater ecosystems, including smothering native vegetation, blocking creeks, reducing water quality by preventing light penetration, reducing oxygenation of water, and choking out fish and other aquatic wildlife.
• Assessment grade and adequacy of information:
  • Queensland is well covered by water quality monitoring at different timescales, from annual report cards in coastal areas to less frequent monitoring in more remote regions. Areas such as the Gulf of Carpentaria and parts of the Murray–Darling Basin have not yet been covered, but will be addressed in future programs.
  • Assessment grades vary from one report card to another, and across time periods.

Victoria

• Key trends:
  • Results from the 2010 Index of Stream Condition report show that 23 per cent of major rivers and tributaries in Victoria were in good or excellent condition, 43 per cent were in moderate condition, and 32 per cent were in poor to very poor condition.
  • Almost half the basins in Victoria have less than 10 per cent of major rivers and tributaries in good or excellent condition. These are mainly in the mid-west of Victoria and have been extensively cleared for agriculture.
  • Results for riparian vegetation show that 21 of 29 river basins had less than 50 per cent of their assessed river length with riparian vegetation in good condition. Basins in the east of the state were generally in better condition than those in the west because of extensive clearing for agriculture.
  • Only 56 per cent of Victoria’s high-value wetlands were assessed as being in good or excellent condition, and 14 per cent were in poor or very poor condition. For wetlands that are not of high value, 51 per cent were assessed as being in good or excellent condition, and 26 per cent in poor or very poor condition.
  • The condition of wetlands on private land was poorer .
  • Fish and amphibian species make up most critically endangered and endangered aquatic species; 43 per cent of amphibians and 55 per cent of freshwater fish are threatened in Victoria.
  • Between 2007 and 2013, 9 inland aquatic vertebrate species declined in status, and 4 species were added to the Advisory List because of decreasing populations. Only 5 species improved their threatened status.
  • In 20 of Victoria’s river basins, non-native fish accounted for 60 per cent of the total fish biomass, and for more than 90 per cent of the total biomass in 7 river basins.
• Assessment grade and adequacy of information:
  • Condition of freshwater aquatic ecosystems: grade—poor; trend—stable; data quality—good.
  • Freshwater biodiversity: grade—poor; trend—deteriorating; data quality—good.
  • Statewide information on the number and distribution of introduced aquatic species remains poor and has not been updated since the 2008 Victorian SoE report.

South Australia

• Key trends:
  • Rivers, streams and drains that are in poor condition typically have elevated levels of nutrients, salt and fine sediment, as well as sparse vegetation and abundant weeds along their banks.
  • Some aquatic pests are increasing (European fan worm—Sabella spallanzanii, and oriental weatherloach—Misgurnus anguillicaudatus).
  • The distribution of European carp is stable, and species such as the alga Caulerpa taxifolia and speckled livebearer (Phalloceros caudimaculatus) are decreasing.
  • The distribution and abundance of aquatic and marine pests are largely unknown.
• Assessment grade and adequacy of information:
  • On average, rivers, streams and drains were assessed as fair. Reliability of information is very good.
  • The assessment grade for aquatic pests is given as unknown, and the reliability of information is poor.
  • The assessment grade for diseases affecting aquatic species is good (South Australia is relatively free from aquatic diseases), and the reliability of information is good.

Western Australia

• Key trends:
  • Fourteen freshwater (nonsubterranean) aquatic fauna species are listed as threatened, and 1 is listed as 'other specially protected'. A subterranean fauna biodiversity hotspot is recognised in the north-west of Western Australia where 3 threatened vertebrate stygofauna are known from karst systems.
  • Aquatic threatened ecological communities are in varying condition, with a drying climate and altered hydrology (salinity, acidity, waterlogging, abstraction, reinjection) impacting on water quality and levels. As a result, vegetation, invertebrates and microbialite (thrombolite/stromatolite-like) assemblages of these communities are generally declining.
  • Hydrological mediation works are improving lake and assemblage condition in some areas.
  • Karst systems, including a threatened ecological community of stygofauna, are affected by physical removal, altered hydrology and altered water quality because of extraction of basic raw materials and minerals. Some springs are also impacted by groundwater drawdown associated with mining below the watertable. In some cases, spring flows and groundwater-dependent vegetation are maintained by artificial supplementation.
  • Approximately 20 per cent of wetlands on the Swan Coastal Plain are considered to retain high values. An analysis of Landsat satellite imagery from 1992 to 2012 indicates that approximately 4 hectares of perennial vegetation within wetlands are lost per day on the Swan Coastal Plain.
  • Water storage in perennial and ephemeral lakes and wetlands has decreased in inland south-western Western Australia, increasing water and soil concentrations of salt, nutrients and sometimes acids. Eutrophication is occurring in some ephemeral wetlands from pastoral livestock. Riparian vegetation is generally declining in areal extent and density, because of declining groundwater levels from declining rainfall and land-use changes. Wetland depth has steadily declined across the south-west, at a rate disproportionately higher than the decline in rainfall that is the primary driver of the change. Soil carbon is decreasing in some organic wetlands, including in the Muir–Byenup Ramsar site.
  • Groundwater-fed springs in the Mandora Marsh Ramsar site (north-western Western Australia) appear stable in extent, but show variable structure and condition. Poor condition is characterised by lower soil carbon, and higher weed and nutrient levels, associated with disturbance by cattle and camels.
  • The invasive redclaw crayfish (Cherax quadricarinatus) has recently been found in natural waters of the Pilbara for the first time. Surveys are being undertaken to determine its extent and inform a management response.
• Assessment grade and adequacy of information:
  • Condition of lakes in threatened ecological communities—fair to good; condition of tumulus springs—excellent; condition of vegetation in threatened ecological communities—fair to good; condition of microbialite threatened ecological community—poor; trend—declining; reliability of information—excellent to fair.
  • Trends in extent and condition of wetlands on the Swan Coastal Plain—declining; reliability of information—good.
  • Wetland condition in inland south-western Western Australia—poor to moderate; reliability of information—good.
  • Extent and condition of groundwater-dependent ecosystems in north-western Western Australia is mostly unknown; trend is uncertain because of limited available information, but some groundwater-dependent ecosystems are artificially supplemented.

Tasmania

• Key trends:
  • Tasmania experienced exceptionally dry climatic conditions during winter–spring 2015 and summer 2015–16.
  • Results from Australian River Assessment System (AUSRIVAS) sampling at 98 sites (60 long-term sites and 38 additional sites) in spring 2015 across Tasmania showed that 52 per cent of the sites were rated as equivalent to reference condition, 32 per cent were significantly impaired, and 16 per cent were severely impaired.
  • Based on the spring 2015 results, the sites can be grouped into those that are
    • in good condition (typically with forested catchments)
    • quite affected (typically in agricultural catchments) and had ratings in spring 2015 that were in line with recent scores
    • very affected (typically in catchments with intense agriculture and/or in rivers that experienced very low flows in winter–spring 2015) and had the lowest ratings they have historically recorded in spring 2015.
  • These results reflect prolonged periods of very low flows in many rivers around Tasmania in winter–spring 2015 and the poor conditions they provide for aquatic fauna. Since May 2016, wetter than average climatic conditions have caused elevated baseflows and flooding in many rivers across Tasmania, which is likely to have improved the condition of some rivers.
• Assessment grade and adequacy of information:
  • Tasmania has a long-term (since 1998) river health monitoring program that employs AUSRIVAS protocols. This monitoring is based on sampling aquatic macroinvertebrates and using their community structure (and predictive models) to rate river condition.
  • Condition of Tasmanian rivers: grade—poor to good; trend—stable to declining; information availability—good.
  • Assessment of data from several organisations external to the Department of Primary Industries, Parks, Water and Environment—including Forestry Tasmania, Hydro Tasmania and NRM regional groups, as part of determining state-specific guideline values for protecting aquatic ecosystems—indicates water quality supporting a range of ecological conditions, from high ecological value, to slightly to moderately disturbed ecosystem value. However, some inland water bodies are considered to have highly disturbed ecosystem value.

Northern Territory

• Key trends:
  • Large feral herbivores are the main immediate threat to many water bodies in the southern arid territory, affecting water quality, water volume and aquatic macroinvertebrates, and the surrounding ground vegetation. This pressure has been partly ameliorated by a large reduction in camel density under the Australian Feral Camel Management Project between 2009 and 2014, and ongoing reduction in feral horse densities in some Aboriginal Lands Trusts.
• Assessment grade and adequacy of information:
  • Freshwater ecosystems in the Northern Territory are generally in good condition, although quantitative data for trends are sparse and patchy.

Aquatic ecosystems

Two aquatic ecosystems were listed as threatened ecological communities under the EPBC Act since 2011: Coastal Upland Swamps in the Sydney Basin bioregion (listed 2014) were listed as endangered, and Seasonal Herbaceous Wetlands (Freshwater) of the Temperate Lowland Plains (listed 2012) were listed as critically endangered. Clearing, altered hydrological processes and invasive species are indicated as ongoing threats to both ecosystems, as well as changed fire regimes and climate change.

Groundwater-dependent ecosystems

Groundwater-dependent ecosystems are geographically small, yet they are an important part of Australian biodiversity. Groundwater-dependent ecosystems are frequently connected to surface waters. In perennial rivers, such as the Daly and Roper rivers of the Northern Territory, permanent base flows are maintained by groundwater inputs during the dry season. Base flows allow fishes to persist through the dry season, and are important areas of production for aquatic invertebrate animals (Pollino & Couch 2014). Few jurisdictions report on the condition of groundwater-dependent ecosystems (however, see New South Wales and Western Australia in Jurisdictional reporting on freshwater species and ecosystems). The New South Wales Government has been actively engaged in identifying groundwater-dependent ecosystems across the state; however, the condition and trend of these ecosystems are largely unknown.

Murray–Darling Basin

The Murray–Darling Basin is a highly modified, regulated river system that covers 14 per cent of the Australian continent and generates approximately 45 per cent of Australia’s irrigated agriculture. It is generally accepted that most flow-dependent ecosystems of the Basin are in poor ecological condition, particularly in the southern Basin, where river regulation and water diversions have resulted in the greatest alterations to flow regimes (Davies et al. 2010, 2012). In response to mounting ecological concerns, the Australian Government initiated major water reforms, culminating in the Water Act 2007 and the Murray–Darling Basin Plan 2012 to address overallocation of irrigation water and restore flows to rivers. The Inland water report graded the state of ecological processes and key species populations in the Murray–Darling as very poor with a deteriorating trend, noting widespread loss of ecosystem function and species population decline.

The South Australian NRM report cards assessed the ecological condition of the Murray River in South Australia as poor, but noted that populations of some communities of aquatic plants, birds and aquatic animals improved between 2010 and 2013 in the Coorong, Lower Lakes and Murray Mouth. Since the millennium drought (which lasted from 2000 to 2010, although in some areas it began as early as 1997 and ended as late as 2012), the condition of river red gums on the floodplains has improved, but the 2013 (partial) Sustainable Rivers Audit found that fish populations in the Murray River channel declined from poor to very poor, and other aquatic animals remained in a moderate condition.

Rivers and riparian habitats

The ecological condition of waterways across Australia is variable; most states and territories (Australian Capital Territory, New South Wales, South Australia, Tasmania, Victoria and Western Australia) report poor to moderate condition of rivers and/or freshwater aquatic ecosystems (see Jurisdictional reporting on freshwater species and ecosystems). Twenty-three per cent of major rivers and tributaries in Victoria were in good or excellent condition.

In northern Australia, aquatic ecosystems (including estuaries, floodplain and riverine) are generally considered to be in overall good ecological condition, notwithstanding areas of localised poor condition (e.g. high riverine disturbance index values for the Fitzroy, Ord, Leichhardt and upper Mitchell rivers). In the arid zone, aquatic systems are considered to be in poorer condition overall because of the impacts of cattle and large feral mammals, as well as losses of some endemic fish and invertebrate fauna in some small spring systems because of introduced fish species. Connectivity of river systems in the arid zone is rated high for most rivers, because the number of impoundments and large dams is low compared with elsewhere in Australia (27 versus 467 dams of more than 0.2 GL).

Data from the Great Barrier Reef Marine Monitoring Program show that overall forest loss in riparian areas continued between 2009 and 2013 (31,000 hectares, or 0.4 per cent) in Great Barrier Reef catchments, with an increased rate of loss compared with previous periods.

Wetlands

Australia has 65 wetlands listed under the Ramsar Convention, with a surface area of more than 8 million hectares. These wetlands are recognised as a matter of environmental significance under the EPBC Act. Australia’s latest report to the Ramsar Convention (DoE 2015b) noted that there is currently no comprehensive national inventory of Ramsar wetlands in place, and it is not possible to definitively state whether the condition of wetlands overall in Australia has improved, deteriorated or stayed the same.

Wetland condition is generally reported by the jurisdictions to be overall poor to moderate (see Jurisdictional reporting on freshwater species and ecosystems); Victoria reports 56 per cent of high-value wetlands in good or excellent condition. Wetland extent is reported as declining in the Swan Coastal Plain and in Queensland. The greatest ongoing losses in Queensland occur in the Murray–Darling and north-east coast areas. Data from the Great Barrier Reef Marine Monitoring Program show that overall loss of wetlands in adjacent catchments continued between 2009 and 2013 (330 hectares, less than 0.1 per cent), although the rate of loss was lower than in previous periods. Wetland extent is reported as stable in New South Wales.

Waterbird communities have been found to be a useful indicator for identifying long-term trends in, and effects of water management on, biodiversity at a range of scales from the entire Murray–Darling Basin, to the Murray River catchment or individual wetlands (Kingsford et al. 2013). The Eastern Australian Waterbird Survey provides baseline information with which to assess changes in, and impacts on, eastern Australian wetlands and rivers. The survey includes estuaries, coastal lakes, rivers, swamps, floodplains and saline lakes, as well as dams, reservoirs and impoundments.

The survey results show that the wetland area across eastern Australia declined in 2015 to below the long-term average (1983–2015; Figure BIO24) (Porter et al. 2014). The 2015 aerial surveys showed that the Macquarie Marshes and Lowbidgee wetlands were partially filled by environmental flows, but these were relatively small areas compared with large flooding years. Most rivers in the Murray–Darling Basin had reduced flows, with mostly dry wetland habitat on their floodplains, including the large lakes of the Menindee Lakes (Porter et al. 2015). Lake Eyre and Cooper Creek wetlands were mostly dry except for a small group of rain-filled wetlands east of Lake Eyre. Other important wetlands were dry, including the Diamantina and Georgina rivers, and lakes Yamma Yamma, Torquinie and Mumbleberry in Queensland. Figure BIO24 illustrates a broad analysis of variation in wetland area during the past 30 years, with a strong correlation with the number of waterbirds in the system (see Terrestrial ecosystems and communities). The Murray–Darling Basin Plan (which came into effect in 2012) has established a coordinated Basin-wide environmental watering strategy across the Basin, agreed to by the Australian Government, and the South Australian, Victorian, New South Wales, Queensland and Australian Capital Territory governments.

Birds

The annual Eastern Australian Waterbird Survey is one of the largest wildlife surveys in Australia. It surveys major wetland sites in the Murray–Darling Basin, and provides invaluable information on the ecosystem health of wetlands and rivers. These surveys have proved particularly relevant in understanding the dynamics of environmental water needs for biodiversity purposes, especially as they relate to waterbirds and wetlands. Changes in waterbird numbers provide a tangible and measurable indication of changes in the ecological health of river and wetland systems.

Trend analyses indicate continued long-term (33 years) declines in total waterbird abundance, breeding species richness and breeding abundance (Figure BIO25) (Porter et al. 2015). These major indices were well below long-term averages. Waterbirds were concentrated in relatively few important sites. Only 4 wetland systems held more than 5000 birds: Lake Killalpaninna, Lake Allallina, Paroo overflow lakes and Coolmunda Dam. These 4 wetlands held a relatively high proportion (20 per cent) of the survey total of waterbirds. In 2015, the total breeding index (all species combined) was the lowest on record and well below the long-term average. Breeding was recorded only in a single location. Breeding species richness was also the lowest on record, comprising 1 nongame species.

Freshwater fish

In Australia, 36 freshwater fishes are listed as nationally threatened under the EPBC Act (Figure BIO26). A further 13 species are nationally listed by the Australian Society for Fish Biology, and another 25 species are listed under state or territory legislation (Lintermans 2013a). In northern Australia, the few freshwater fishes listed as threatened include elasmobranchs of high conservation significance, such as freshwater sawfish (Pristis spp.) and river sharks (Glyphis spp.). Of the more than 100 species of freshwater fish in northern Australia, only 6 species are listed in the lower risk, near threatened or data-deficient categories by the IUCN. Of these, it is now considered that 2 species (freckled hardyhead—Craterocephalus lentiginosus, and elongate glassfish—Ambassis elongatus) should be removed, based on recent better understanding of distributions. Another of these 6 (purple-spotted gudgeon—Mogurnda adspersa) is listed based on threats it faces in south-eastern Australia.

Currently, about 300 species of Australian freshwater fish are recognised from 59 families (Faulks et al. 2015). However, this knowledge is incomplete, because more species are being described with the aid of molecular and taxonomic surveys, so true species richness may exceed this estimate. Although this is a relatively small number compared with other continents, approximately 70 per cent of Australian inland fish species are endemic; further, they show unusual adaptations to highly varying environmental conditions. The highest endemism is found among the central, southern and western basins that are characterised by aridity and long-term isolation (Pollino & Couch 2014).

The distribution of northern Australian fishes is better understood than in SoE 2011 because of recent survey work, and compilation of historical and museum records. However, recent phylogeographic research highlights the potential presence of many undescribed cryptic species. Furthermore, in northern Australia, invasive non-native fish species are limited in number (5); instances of occurrence are largely limited to peri-urban areas, and most involve ornamental species.

In southern Australia in 2014, the New South Wales Department of Primary Industries confirmed that a population of the introduced tilapia species, Mozambique tilapia (Oreochromis mossambicus), had become established on the New South Wales far north coast; this was the first confirmed population of tilapia in the state. Three species of tilapia (Mozambique tilapia, spotted tilapia—Tilapia mariae, and redbelly tilapia—T. zillii) have established successful breeding populations at several sites in Queensland, Victoria and Western Australia. Populations of Mozambique tilapia in southern Queensland are as little as 3 kilometres from the Condamine–Balonne rivers catchment of the Murray–Darling Basin, posing a significant threat to the native fish of the Basin.

The distribution of currently listed threatened freshwater fish species is concentrated in south-eastern and south-western Australia and Tasmania. Although no Australian freshwater fish is known to have become extinct since European settlement, there is evidence of regional extinctions, particularly in south-eastern Australia (Lintermans 2013b). Recovery actions have saved several species (Pedder galaxias—Galaxias pedderensis, and barred galaxias—G. fuscus) from extinction and the Mary River cod (Maccullochella mariensis) from near extinction (Lintermans 2013a). Pedder galaxias persists only as 2 translocated wild populations outside its natural range.

Some 13 per cent of Australian freshwater fishes are recognised as nationally threatened (listed as conservation dependent, vulnerable, endangered, critically endangered or extinct under the EPBC Act). None has ever been downlisted or delisted, suggesting that ongoing management is critical (Figure BIO27). A study published in 2016 (Le Feuvre et al. 2016) identified a further 55 species that are potentially vulnerable, and highlighted the vulnerability of northern Australia’s freshwater fishes to extinction. Three hotspots of potential extinction risk were identified: the Kimberley region, the Wet Tropics and, to a lesser extent, Arnhem Land. All 16 species identified as potentially vulnerable in the Kimberley region are endemic to that region, whereas the Wet Tropics and Arnhem Land had higher proportions of broader-range species.

A national survey of on-ground recovery actions for listed freshwater fish (Lintermans 2013b) reported 428 on-ground recovery actions in Australia, with the majority in the Murray–Darling Basin and south-eastern Australia. However, few or no recovery actions were reported for many species, with no coordinated plan to deal with their state, and few actions occurred in northern or western parts of the country.

Invertebrates

The Murray River Macroinvertebrate Monitoring Program systematically samples and records aquatic macroinvertebrate populations along the Murray River and its major tributaries. The program has been operating since 1980 and is a rare example of a long-term monitoring program, especially for aquatic fauna. The surveys revealed a substantial decline in biological health throughout the Murray River between 1996 and 2010 (also referred to as the millennium drought). During this period, species that are associated with poor water quality, habitat and flow conditions increased in diversity and abundance, whereas sensitive species declined. Data analysis from the 2 years after the 2010 flood event shows some evidence that communities are returning to a before-drought state; however, monitoring during the next few years will be needed to confirm the extent to which this occurs (Paul et al. 2013).

Tasmania is home to some very unusual freshwater crayfish. Fifteen species of Engaeus occur in Tasmania, 13 of which are endemic, with highly restricted distributions. Because of a range of factors, such as habitat loss, changed hydrology and the degradation of water catchments, some are listed as threatened species. Five species have been listed as threatened at both the state and national level, and are the focus of a recovery plan.

Australian subterranean fauna are increasingly being recognised and investigated, as highlighted in Box BIO12.