Urban expansion, climate change & frog habitat

Who’d be a frog in the suburbs? Not only do they have to contend with habitat loss, fragmentation and degradation, now there’s climate change, too. Joab Wilson and colleagues have tried to better understand the separate impacts that climate change and urbanisation might be having on frogs. Of course, the two processes are overlapping and interacting. A frog’s ability to migrate to more suitable habitats in response to increasing temperatures (connected to climate change) may be reduced in more fragmented landscapes (connected to urbanisation). However, given the large uncertainties surrounding climatic predictions at the scale of cities and the unpredictable nature of ecological communities, it will be challenging to accurately predict how species may respond to future climatic events.

Our study produced a series of best- to worst-case climate and urbanisation scenarios for the suitability of pond habitat for the spotted marsh frog in the urban fringe of Melbourne. It’s expected that ponds will become less suitable as habitat as they become increasingly dry under the climate change scenarios. However, we wanted to see what this might mean under different development pathways in the suburbs.

We found that pond habitats in the Merri Creek catchment are likely to become less suitable for amphibians under both climate and urbanisation scenarios. An increasingly warm and dry climate is likely to provide less standing water for species to be able to breed and for tadpoles to develop.

An important finding to note, however, is that in the short term it’s urban development that poses the much greater risk, making ponds significantly less suitable for the species to persist. And that gives us something that lies within our power to do something about. Our ability to control the effects of urban development on the habitats provided by the Merri Creek corridor is something we can engage with at the local and regional scale whereas mitigating climate change requires concerted effort at all scales.

When you consider how much attention is being given to climate change while so little is being given to the impacts of urban expansion, it could be we are ignoring the elephant in the room.

See Decision Point #63 for the complete story

Urban development in the Merri Creek catchment is likely to carry a heavy impact for amphibians

Urban development in the Merri Creek catchment is likely to carry a heavy impact for amphibians


Reference

Wilson JN, S Bekessy, KM Parris, A Gordon, GW Heard & BA Wintle (2012). Impacts of climate change and urban development on the spotted marsh frog (Limnodynastes tasmaniensis). Austral Ecology.DOI: 10.1111/j.1442-9993.2012.02365.x

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