Urban Areas Become Centres Of Biodiversity: Macquarie University
Cities have become arks of
biodiversity and there are more species of trees in urban spaces than imagined,
according to scientists at Macquarie University. The findings were based on
analysis of 12 million tree planting records, collected by local governments in
almost 500 cities and towns globally. Urban spaces make up only 2 percent of
Earth's land mass -despite what our perceptions might tell us. A sample study
of urban areas revealed they contained 47234 tree species- about 8% of the
world's known tree species. Extrapolating from this sample to all urban areas,
they estimate that cities and towns might hold as much as one sixth of global
Of the urban trees the researchers catalogued, one-tenth face conservation risk in the wild, according to the International Union for Conservation of Nature’s Red List of Threatened Species. Six of the species they found are thought to be extinct in the wild. The researchers were only able to collect data on trees in public spaces, meaning there may be even greater diversity present if backyard plantings are factored in.
Dr Alessandro Ossola, ecologist in Macquarie's Department of Biological Sciences and lead author of the study, says urban tree species diversity is well-rooted in human history. “Urban areas represent an overlooked opportunity for plant conservation globally. Our study suggests that meaningful biological conservation of plant diversity can be done on our very doorsteps – in our suburbs and home gardens”, Dr Ossola says.