The influence of urbanisation on wetland invertebrate biodiversity — ASN Events

The influence of urbanisation on wetland invertebrate biodiversity (#136)

Teresa J Mackintosh 1 , Ross Thompson 2 , Jenny Davis 2
  1. School of Biological Sciences, Monash University, Clayton, VIC, Australia
  2. Institute for Applied Ecology, University of Canberra, Canberra, ACT, Australia

The construction of wetlands in the urban environment is primarily carried out to assist in the removal of contaminants from wastewaters, however they have the added benefit of providing habitat for wildlife.  Nonetheless, stormwater can be a threat to aquatic environments as the quantity and quality of stormwater decreases as impervious area (roads, sealed areas, roofs) increases.  Total imperviousness (TI) is the measure used to quantify the amount of catchment imperviousness associated with urbanisation.  This study aims to establish whether the degree of urbanisation and its associated change in stormwater runoff affects macroinvertebrate species richness and abundance within constructed wetlands.  Urban wetlands in Melbourne’s west and south east were sampled along a gradient of urbanisation.  There was a significant inverse relationship between TI and the abundance of macroinvertebrates detected. Chironomidae (non-biting midges), was the most abundant family recorded at the majority of sites.   Chironomids are able to tolerate a wide array of environmental conditions, including eutrophic and anoxic conditions.  As such, they are often the dominant taxa in urban wetland systems.  It is likely that the overall decrease in water quality associated with increasing amounts of stormwater runoff was detrimental to the invertebrates within these wetland systems.  It is important to understand the impacts of urbanisation on aquatic biota to ensure that urban wetlands can be designed and managed to continue to provide important habitat for wildlife.

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