Indicator: Aquatic macro-invertebrates

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What the results tell us for Tumut

See also: | Surface water quality |

Over half of the sites for which river health data are available within the Tumut Shire area are in good condition, with the remaining monitored streams and rivers in either a fair or poor condition (Table 1). This result indicates that river health is an issue in this Shire requiring some attention.

Table 1. River health monitoring sites and their condition rating
Site Name/NumberSite LocationCondition Rating
BIDG104Goobarragandra River at Flat Rock ReserveMinimal human impact
BIDG107Jounama Ck at TalbingoMinimal human impact
BIDG517Gilmore Ck at Gundagai Rd TumutMinimal human impact
BIDG725Brownleys Back Ck down stream of YarrongobillyMinimal human impact
BIDGM2Bago CkMinimal human impact
BIDG129Yarrongobilly River at Ravine20-50% of expected animals missing
BIDG518Goobarragandra River at Kell Rd20-50% of expected animals missing
BIDG512Tumut River at Snowy Mountains Hwy50-80% of expected animals missing


About the data

Data on the presence and absence of aquatic macro-invertebrates were provided by the NSW Environment Protection Authority, as part of the Australia wide AUSRIVAS assessment program.

The AUSRIVAS method provides an assessment of invertebrate diversity in a stream section at 'test sites' in relation to 'reference sites'. Test sites are of unknown or suspect biological condition, whereas reference sites are sites which are considered minimally disturbed or affected by humans (that is, they have intact riparian zones, no stock access, several kilometres from a barrier, no road crossing within the vicinity etc.). Test and reference sites share similar environmental features unlikely to be influenced by human activity (for example: latitude, elevation, channel slope, alkalinity, etc).

The AUSRIVAS results are provided as a ratio value of observed : expected species present. A value of one (1) indicates that a test site is equivalent to reference sites, and a value of less than 0.8 indicates impaired species diversity. The current version of AusRivAS is preliminary, being based on just the first few years of sampling data, and so its results must be treated as indicative only. For this reason, the assessments over time for each site have been aggregated to give indicative site ratings ranked as follows:

Good
• above reference with about 20% or more of the different kinds of animals than expected (Band X)
• equivalent to reference, showing minimal human disturbance and/or impact (Band A)
Fair
• below reference with a loss of between about 20–50% of the different kinds of animals expected (Band B)
Poor
• well below reference with a loss of between about 50–80% of the different kinds of animals expected (Band C)
Very poor
• impoverished with more than about 80% of the kinds of animals expected (Band D)

Further information on the AUSRIVAS program and method of assessment can be obtained from the following website:
http://ausrivas.canberra.edu.au

Shire river health assessments can can be obtained from the Environment Protection Authority website at
http://soedirect.nsw.gov.au/app/index.jsp

Description: What does 'aquatic macro-invertebrates' measure?

Which data are collected?
  • aquatic health at river test sites, based on the composition of their macro-invertebrate fauna as assessed by the AUSRIVAS model
Why do we report this indicator?

The ecological health of streams, including waterbodies, is reflected in the diversity and number of aquatic fauna and flora. Activities in the catchment which impact on stream habitat or water quality will generally be reflected in the status of this indicator. Only macro-invertabrates are considered in this indicator, the status of other flora and fauna is considered separately.

The AUSRIVAS model used to calculate a value for this indicator is based on a comparison of invertebrate richness in a stream reach in relation to that at nearby reference sites with a similar habitat that have not been degraded in any way.

Description: What does 'aquatic macro-invertebrates' measure?

Which data are collected?
  • aquatic health at river test sites, based on the composition of their macro-invertebrate fauna as assessed by the AUSRIVAS model
Why do we report this indicator?

The ecological health of streams, including waterbodies, is reflected in the diversity and number of aquatic fauna and flora. Activities in the catchment which impact on stream habitat or water quality will generally be reflected in the status of this indicator. Only macro-invertabrates are considered in this indicator, the status of other flora and fauna is considered separately.

The AUSRIVAS model used to calculate a value for this indicator is based on a comparison of invertebrate richness in a stream reach in relation to that at nearby reference sites with a similar habitat that have not been degraded in any way.