“Where Them Birds At?!”
Species are going extinct at an alarming rate, with these losses even visible in our own back gardens. Urban development, through intensification and expansion, poses a serious threat to wildlife living in green spaces scattered around cities. Protecting and restoring green spaces is important, as cities often overlay highly productive areas that are hotspots for biodiversity. The salience of wildlife in cities is also one way to connect people to nature, and to promote a conservation ethic among society.
To conserve urban bird diversity, habitat restoration is often implemented by local councils, non-government organisations and environmental consultancies. These agencies promoting conservation in cities often cite “increasing biodiversity” as a common goal when implementing habitat restoration. This goal is vague at best, as clearly some species can be viewed as more valuable conservation targets than others. Increasing populations of common birds like noisy miners and magpies probably isn’t synonymous with increasing small song birds like fairy wrens and silvereyes. It is important to identify how individual bird species and groups of birds are interacting with habitat restoration actions to ensure these efforts are promoting the species which we want to inhabit our urban parks.
Habitat restoration actions are expensive to implement and are expected to benefit urban bird diversity, although birds known to be sensitive to urbanisation may not be interacting with restoration in the ways we anticipate. Controlling weedy plant species, such as lantana, and revegetating of native species are two common restoration actions — and we wanted to know if these restoration actions are benefiting birds that find living in cities hard; or are the benefits of urban restoration falling on the laps of species who already call cities home?
We explored how bird species with varying sensitivities to the challenges of living in urban areas interact with revegetation and weed control. We surveyed birds in local council owned restoration sites maintained by community members through revegetation and weed control in Brisbane, Australia. We then applied a hierarchical community model to estimate the response of urban exploitative, adaptable and sensitive bird species to these management actions. This allowed us to create probability curves of individuals and species group responses to urban restoration. Providing probabilities of ‘success’ for individual species and species groups expands the information available to land managers within their decision-making space.
Contrary to the belief that all restoration activities will have positive impacts on bird diversity, we found that birds most reliant on nature in cities in seem not to benefit in patches that have been controlled for weeds, while birds which exploit the urban environment benefit. These shifts in diversity could be a product of the removal of shrubby habitat needed by urban sensitive species or could be an effect of territorial species such as noisy miners infiltrating and displacing birds in these areas. This could have serious implications for urban bird diversity, which may have flow on implications to the way in which cities experience and relate to nature. Revegetation, however, seems to benefit all groups of species richness, even though some individual species may suffer abundance declines.
Habitat restoration is a common conservation practice in cities, and we put a lot of money and effort, especially in community managed spaces, to make sure these areas successful. To achieve a greater conservation benefit from these areas, especially for birds that rely on these greenspaces a change in the way we are implementing these action is needed. To increase bird diversity within cities, we need to disentangle the effect of habitat restoration actions and make sure we are managing these areas with urban sensitive species in mind.
Check out the video I made about this research!
Archibald, C.L., Mc Kinney, M., Mustin, K., Shanahan, D.F. & Possingham, H.P. (2017) Assessing the impact of revegetation and weed control on urban sensitive bird species. Ecology and Evolution, 1–10 http://onlinelibrary.wiley.com/doi/10.1002/ece3.2960/full