HR: 10:45h
AN: NB22F-02    [Abstracts]
TI: An Inter-City Comparison of Macroinvertebrate Assemblage Response to Urban Land use in Southeastern Australia
AU: * Walsh, C J
EM: Chris.Walsh@sci.monash.edu.au
AF: Cooperative Research Centre for Freshwater Ecology, Water Studies Centre, Monash University, Clayton, Vic 3800 Australia
AU: Padgham, M
AF: Cooperative Research Centre for Freshwater Ecology, Water Studies Centre, Monash University, Clayton, Vic 3800 Australia
AB: The relationship between macroinvertebrate assemblage composition and two measures of urban land use was assessed in 2 Australian cities: subtropical Brisbane and temperate eastern Melbourne. Average annual rainfall is similar in the 2 regions (900-1200 mm across eastern Melbourne, 1100-1200 mm across Brisbane). However, in Melbourne, rainfall is more frequent, more evenly distributed, and generally less intense. In both cities effective imperviousness (EI, including only those impervious surfaces with direct sealed connections to a stream) was a stronger predictor of assemblage composition than was total imperviousness. In both cities, compositional similarity (as portrayed by a 1-dimensional multidimensional scaling) declined linearly from sites with zero EI to a threshold of maximum degradation at 6-10% EI. The similarity of pattern in 2 cities of differing climate suggests strong impacts of stormwater runoff at very low levels of urbanization, independent of rainfall pattern. The influence of climate on instream urban impacts will be explored further with similar models being developed for two drier regions: western Melbourne and Canberra, each with approximately 600mm annual rainfall.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly