Something happened 20 years ago that set the wheels in motion for my life in the swamps. On September 24 1993 International Olympic Committee President Juan Antonio Samaranch announced that Sydney had successfully won the right to host the Olympic Games in the year 2000. With those now famous words, “and the winner is…Sydney”, my path towards a life of research into mosquitoes and wetland rehabilitation had begun. Not that I realised this at the time.
In September 1993 I was nearing the completion of a BSc at Macquarie University. Although I was thinking about continuing with Honours the next year, a PhD was still a long way from my mind. I was probably worrying more about securing tickets to the following year’s Big Day Out to see Teenage Fanclub and the Breeders than launching my research career. I certainly had no idea at the time how important the 2000 Olympics announcement would be for me.
Although the area around Homebush Bay had been earmarked for redevelopment for a long time, it was the announcement that this was to be the central location for the 2000 Olympics that really kicked off the transformation of the site. Most importantly for me, it wasn’t just the sporting and accommodation facilities that were being built that was important, it was the major wetland rehabilitation projects planned that provided me with a life changing opportunity.
Mosquitoes had been a problem around Homebush Bay, and parts of the Parramatta River, for a long time. There had been reports of nuisance-biting problems and mosquito control programs in the local region since the 1920s. There was even a push from the community in 1929 to spray kerosene on local wetlands from an aeroplane to control mosquitoes!
During the 1980s, the pest mosquito problems began to intensify as local communities around Homebush Bay complained to local authorities about how unpleasant life had become during the summer months. One of the problems, as I would find later during my PhD candidature, was that the unusually high mosquito populations were really symptomatic of the poor health of the estuarine wetlands. The shoreline along Homebush Bay and the Parramatta River had been heavily modified and this had restricted the flow of tides and rainfall runoff into and out of the wetlands. The wetlands had become clogged with large areas of stagnant water. As well decreasing the health of the wetlands, it enhanced conditions for the production of pest mosquitoes.
The most important pest mosquito was the saltmarsh mosquito, Aedes vigilax. This species is a severe nuisance-biting pest, disperses many kilometres from wetlands and is closely associated with outbreaks of mosquito-borne disease. Along the east coast of Australia, this species has been identified as playing a key role in the transmission of Ross River virus and Barmah Forest virus during epidemics.
Along the Parramatta River, the risks of mosquito-borne disease are minimal as there are no native animals (i.e. kangaroos and wallabies) that act as reservoirs for the mosquito-borne viruses. However, large populations of these mosquitoes can still cause a problem due to their nuisance-biting.
A large section of wetlands at Homebush Bay was contained within the Royal Australian Navy Armament Depot (RANAD) Newington (commonly known as the Newington Armory). This site was operated as a ammunition depot from 1897 through until 1999. With a desire to better understanding the environmental drivers of pest mosquito populations and to develop environmentally sustainable strategies to reduce the mosquito populations, the Australian Government Department of Defence provided funds to support a PhD project through the University of Sydney.
I had just finished my BSc (Hons) at Macquarie University investigating the response of ant populations in rehabilitated coastal sand dunes and the role of mosquitofish in Sydney’s declining frog populations. I’d developed a love of research and started looking around for projects. I was originally interested in a project studying bird populations associated with rehabilitated urban streams but that didn’t quite work out. Someone passed on the details of a PhD scholarship with the University of Sydney to investigate mosquitoes. I was fortunate to be awarded that scholarship and haven’t looked back.
What I love most about working with mosquitoes is that they’re a link that connects many aspects of environmental science, entomology, public health and scientific communications. Mosquitoes, particularly Aedes vigilax, are Australian native animals that have adapted to a specific, and particularly harsh, ecological niche. These estuarine wetlands, particularly saltmarshes, where the mosquitoes are found are also important and threatened ecosystems. Perhaps the mosquitoes are also vital components of these ecosystems as a food source for insectivorous animals?
While it is certainly true that large populations of mosquitoes can be produced from healthy natural wetlands, I am finding that unusually large mosquito populations are often found in association with degraded wetlands, particularly those in urban areas. The work I’ve done documenting the ways in which degraded wetlands can be rehabilitated, while reducing mosquito populations, will hopefully assist in the development and willingness of local authorities to undertake rehabilitation projects.
I’ve come to realise that mosquito management needs to be a key component of wetland management. Notwithstanding the duty of care wetland managers have to reduce potential public health impacts, engaging the community to care about wetlands and their conservation will always be much harder if visitors are chased away by swarms of biting mozzies. Effective mosquito management can help wetland conservation!
Together with the Sydney Olympic Park Authority, I’ve had an opportunity to incorporate my ongoing research into the development of ecologically sustainable mosquito management strategies. We’ve conducted a number of projects that have restored tidal flushing to degraded areas of mangroves to improve the health of the wetlands while also reducing the need for mosquito control. In areas where mosquito control is required, a detailed surveillance and assessment program is in place that ensures that mosquito population increases are minimised without any adverse impacts to the local environment.
The other benefit of working closely with the Sydney Olympic Park Authority has been the opportunity to work with them on educating the community and a range of professionals on the importance of wetland conservation. Whether it is public lectures, speaking to school groups or coordinating workshops on wetland management techniques, it has been a pleasure to share my experiences and knowledge with new groups of people.
I think that there was a time when mosquito control operations were perceived as being at odds with wetland conservation but I argue strongly at every opportunity that an integrated approached to wetland management, that includes mosquito management, is critical. Once wetlands were drained or filled to control mosquitoes, now tidal flows and predator populations are promoted to reduce the suitability of wetlands for pest mosquitoes.
Now, on the 20th anniversary of that historic announcement by Juan Antonio Samaranch, I’m taking some time to reflect on what turned out to be a very fortunate opportunity for me. That opportunity introduced me to the world of mosquitoes and has allowed me to continue that work in one of the most interesting wetland rehabilitation projects in Australia.