Introduction
In a changing world of urbanisation and climate change mosquitoes are an important consideration for wetland management. Mosquitoes can be a general nuisance to humans but certain species of mosquitoes are able to act as vectors for disease, posing a potential health risk. Mosquitoes breed in a range of waterbodies, these may vary in size, and permanency, with various habitat attributes.
Melbourne Water has over 350 wetlands that have not been assessed for their mosquito risk, including natural wetlands, stormwater retention basins, sewerage treatment lagoons and billabongs. Most wetland sites have limited monitoring data for mosquito species and abundance. A robust and efficient way was required to assess the mosquito risk each wetland posed.
Methods
The approach was to use Multi Criteria Assessment (MCA) to prioritise the likelihood of high risk mosquito conditions at each site. Specific wetland characteristics were established that are known predictors of mosquito breeding likelihood. Weighting for the predictor variables was developed based on known thresholds and conceptual understanding of significance of each factor. Risk ratings of wetlands were tested with key mosquito managers in Victoria to validate findings and refine the results.
Outcomes
The use of MCA allowed for a large number of sites to be assessed for mosquito risk without the need for physical monitoring or assessment. Risk was defined for wetlands enabling prioritisation for management based on robust science and validated criteria. Knowledge gaps and sites with insufficient data were also identified during the processes allowing these sites to also be prioritised. The technique, allows for the data set and risk to be updated if there are wetland changes or more data becomes available. The approach demonstrates that MCA is an excellent technique for assessment of mosquito risk for a large number of wetlands when mosquito monitoring data is not always available.