Factors affecting river health and its assessment over broad geographic ranges: the Western Australian experience |
| |
Authors: | Halse S A Scanlon M D Cocking J S Smith M J Kay W R |
| |
Institution: | (1) Science Division, Department of Environment and Conservation, P.O. Box 51, Wanneroo, WA, 6946, Australia;(2) Present address: Waterways Unit, Maryoochy Shire Council, P.O. Box 76, Nambour, QLD, 4560, Australia;(3) Present address: Nature Conservation Division, Department of Environment and Conservation, Locked Bag 104, Bentley Delivery Centre, Bentley, WA, 6983, Australia |
| |
Abstract: | AusRivAS is an Australia-wide program that measures river condition using predictive models to compare the macroinvertebrate
families occurring at a river site with those expected if the site were in natural condition. Results of assessment of 685
sites across all major rivers in Western Australia are presented. Most rivers were in relatively natural condition in the
northern half of the state where the human population is low and pastoralism is the major land use. In the south, where the
human population is higher and agriculture is more intensive, rivers were mostly more disturbed. AusRivAS assessment produced
some erroneous results in rivers of the south-west cropping zone because of the lack of appropriate reference site groups
and biased distribution of sampling sites. Collecting low numbers of animals from many forested streams, because of low stream
productivity and samples that were difficult to sort, also affected assessments. Overall, however, AusRivAs assessment identified
catchment processes that were inimical to river health. These processes included salinisation, high nutrient and organic loads,
erosion and loss of riparian vegetation. River regulation, channel modification and fire were also associated with river degradation.
As is the case with other assessment methods, one-off sampling at individual sites using AusRivAS may be misleading. Seasonal
drought, in particular, may make it difficult to relate conditions at the time of sampling to longer-term river health. AusRivAS
has shown river condition in Western Australia is not markedly different from other parts of Australia which, as a whole,
lacks the substantial segments of severely degraded river systems reported in England. |
| |
Keywords: | AusRivAS Macroinvertebrates Salinisation Environmental impacts Temporal variability Sample size |
本文献已被 PubMed SpringerLink 等数据库收录! |
|