Estimates of the impact climate change will have on wildlife may be much less reliable than thought, according to research that is reopening debate over a widely used modelling method endorsed by the Intergovernmental Panel on Climate Change (IPCC).
Could more than 60% of 'climate envelope' studies be wrong?
Estimates of the impact climate change will have on wildlife may be much less reliable than thought, according to research that is reopening debate over a widely used modelling method endorsed by the Intergovernmental Panel on Climate Change (IPCC).
'Climate envelope' models use current distributions of species to construct an idea of the climatic conditions that suit them. This 'envelope' can then be used to see where species could live under predictions of future climate.
Use of climate envelope models has been contentious, not least because they omit a number of factors that may be as or more important than climate in controlling species distribution, for example human activity, interactions with other species and pure chance.
Now a paper from Colin Beale of the UK's Macaulay Institute of Land Use Research, in Aberdeen, and colleagues has cast further doubt on the value of climate envelope models, saying they quite frequently do no better than chance in explaining why species live where they do. "At the moment people are overconfident in our ability to make these projections," says Beale. "We really need to start to think about models that include a lot more biology." The work is published in Proceedings of the National Academy of Sciences1.
Where the birdies aren't
Beale and his colleagues began by generating climate envelopes based on real distribution data for 100 European bird species. Then they created 99 artificial distribution patterns for each of the real patterns. These 'null' distributions were designed to mimic the spatial structure of the birds' real distribution, but were created with no reference to climate at all. So while the real distribution of, for example, the serin (Serinus serinus) might run from Portugal to Eastern Europe, the artificial distributions might have the bird up in Scandinavia but absent from Iberia.
