Biodiversity-sensitive cities - fact or fiction?
With six billion people predicted to live in cities by 2050, urbanisation is now recognized as one of the most pervasive and destructive forms of human activity, altering entire ecosystems and threatening global biodiversity.
Darren Le Roux's PhD, is investigating the biodiversity sensitivity of the urban greenspace. He has found that relative to adjacent nature reserves, urban greenspace supports far fewer mature native trees, tree hollows, dead trees, logs, litter, shrubs and regenerating seedlings.
Le Roux argues: “we can’t expect wildlife to persist in our urban landscapes without first ensuring that the necessary habitat structures they depend upon for survival are retained and protected.”
One of the major conservation challenges in cities is the public perception that certain habitat structures are either hazardous or unattractive; eg. logs, litter and shrubs may represent a bushfire risk for some residents. The perceived threat of these "risks" in turn facilitates their intentional removal and the ‘tidying up’ of such resources within the urban greenspace.
Le Roux says “highly manicured greenspaces are the norm in cities, but this may not be the best approach for wildlife. We need to get a bit more messy and start finding strategic ways to balance socio-economic interests while also retaining habitat for wildlife, thereby creating a ‘shared space’ in our parks, roadside margins and backyards”.
Le Roux’s research also reveals that the classic Aussie icon, the old large eucalypt tree, may soon be a thing of the past in our cities. He warns “simulation models of native tree populations indicate that large old trees could be completely lost from the urban greenspace within 115 years without immediate intervention”.
Only large old trees, with their hollows and large quantities of flowers, nectar and peeling bark can provide the unique habitat resources for a myriad of species. “Unfortunately, large trees are too often removed due to perceived threats such as limbs dropping, damaging people and property. Practical ways need to be found to retain and protect large trees rather than simply cutting them down”. Large trees take hundreds of years to mature and can live for 500 years.
Darren’s ongoing research aims to formulate innovative management strategies that will inform habitat protection policies, assist on-the-ground wildlife conservation efforts and help mitigate ongoing urban development impacts in the urban landscape, making the concrete jungle more sustainable and habitable for future generations of wildlife.