Indicator: IW-30 Macroinvertebrate condition

Data

Aquatic biota index (macro-invertebrates) results for each State and Territory
Total length of reach (km) in each category and percentage of total in parentheses Percentage of total length with data
Reference Significantly impaired Severely impaired Extremely impaired
Queensland 9 334 (80) 1 997 (17) 250 (2) 16 (1) 16
New South Wales 11 366 (50) 7 551 (34) 2 801 (13) 690 (3) 38
Australian Capital Territory 169 (64) 76 (29) 17 (7) 0 (0) 97
Victoria 9 347 (76) 2 447 (20) 344 (3) 49 (1) 77
Tasmania 4 248 (75) 1 097 (20) 142 (3) 100 (2) 100
South Australia 7 866 (83) 1 098 (12) 124 (1) 389 (4) 98
Western Australia 4 401 (64) 1 977 (29) 419 (6) 31 (1) 27
Northern Territory 2 063 (88) 247 (10) 47 (2) 0 (0) 11
Total 48 793 (69) 16 490 (23) 4 144 (6) 1 275 (2) 34

Source: National Land and Water Resources Audit 2001, Australian Catchment, River and Estuary Assessment 2002, Volumes 1 and 2, Land and Water Australia, Canberra, viewed 15 Nov 2005, http://audit.ea.gov.au/ANRA/coasts/docs/estuary_assessment/River_Findings.cfm.

River condition, Queensland

River condition, Queensland

Source: Department of Natural Resources and Mines 2004, Priorities in Progress report 2003-4: A clean, liveable and healthy environment, Queensland Treasury, viewed 23 Nov 2005, http://www.treasury.qld.gov.au/office/knowledge/docs/priorities/2003-04/subsections/clean_livable_healthy.pdf.

Sites assessed using AusRivAS, all states and territories, 1990-2004
Number of sites at each level of diversity compared with reference sites
Period of assessment More diverse Similar to reference condition Significantly impaired Substantially impaired Severely impaired Total number of test sites
1990-2004 195 2 465 1 556 433 56 4 705
1994-99 (in SoE2001 ) 154 1 702 963 254 39 3 112

Source: Department of the Environment and Heritage 2003, Australian River Assessment System ( AusRivAS), National River Health Database, Department of the Environemnt and Heritage.

Interim Indicator: River Health River Condition - Sites per AusRivAS Band (Interim NRHP River Health Assessment, all states and territories, 1990 - 2004)

 River Health River Condition - Sites per AusRivAS Band (Interim NRHP River Health Assessment, all states and territories, 1990 - 2004)

Source: Australian River Assessment System (AusRivAS) 2005, National River Health Database, viewed 23 Nov 2005.

What the data mean

One-third (21 909 km) of river length is impaired to some degree (has lost between 20% and 100% of the various kinds of aquatic invertebrates that should live there). New South Wales has the poorest aquatic biota condition; approximately 50% of river length has impaired aquatic biota

In Queensland, the percentage of sites considered to be in a condition similar to reference decreased from 2001 to 2002, while the percentage of sites considered to be significantly impaired has increased.

The national Australian River Assessment System (AusRivAS) data show a significant number of sites that are more impaired than the reference sites.

Data Limitations

Assessment results are underestimates of change in some parts of the country, including the lowland rivers of the Murray-Darling Basin and Western Australia, where reference sites used as benchmarks have already been modified to some extent since European settlement.

Many of the sites sampled in Queensland in the two years are different and therefore the results may reflect differences between catchments and climatic variability between years.

The error margin or confidence intervals for AusRivAS indices have not as yet been precisely quantified.

All data are presumed to be correct as received from data providers. AusRivAS results depict only the most recent combined season score furthest from reference condition, where available (or the single season habitat score furthest from reference condition where a combined season score is not available) recorded during the assessment period.

Issues for which this is an indicator and why

Inland Waters - Response of biota - Macroinvertebrates 

As well as being an indicator of river condition, macroinvertebrate populations are an important aspect of freshwater biodiversity in their own right. Their condition is readily measured because they are widespread, easy to sample and relatively immobile.

Other indicators for this issue:

Inland Waters - Habitat scale influences - In-stream habitat - woody debris and sand slugs 

Macroinvertebrates are widespread, easy to sample, relatively immobile, and most importantly, their composition reflects the historical impact of environmental changes on the stream ecosystem for up to several months before sampling. They therefore provide an ‘integrated’ indicator of human impact on the stream ecosystem.

Other indicators for this issue:

Biodiversity - Species, habitats and ecological communities - Conservation status of species and ecological communities 

Aquatic macroinvertebrates are a diverse group of animals that include a range of insect, crustacean and molluscan groups such as snails, water boatmen, dragonflies, stoneflies, mayflies and aquatic worms. As well as being an indicator of river condition, macroinvertebrate populations are an important aspect of freshwater biodiversity and ecological communities in their own right. Their condition is readily measured because they are widespread, easy to sample and relatively immobile.

Other indicators for this issue:

Biodiversity - Species, habitats and ecological communities - Condition of freshwater biodiversity 

Aquatic macroinvertebrates are a diverse group of animals that include a range of insect, crustacean and molluscan groups such as snails, water boatmen, dragonflies, stoneflies, mayflies and aquatic worms. Their composition reflects the historical impact of environmental changes on the stream ecosystem for up to several months before sampling. They therefore provide an ‘integrated’ indicator of human impact on the stream ecosystem.

Other indicators for this issue:

Further Information