Human activities have reduced natural habitats to isolated “islands”, making it more difficult for some species to re-locate to cooler regions in response to their existing locations growing warmer.
The new study by researchers in the Department of Biology at York, published in the journal Conservation Letters, has used population models to show that many species could not successfully colonise the fragmented habitats of Yorkshire and Humber.
But current plans for habitat re-creation across the region could help some species at least, making the difference between colonising and being marooned.
The research team found that, for three out of four habitat types, the most efficient strategy was to create a system of stepping stones linking existing habitat clusters. Alternatively, adding re-creating habitat patches randomly across the region was a reasonably successful strategy for all habitat types. But placing restored habitat close to the largest areas of existing habitat gave virtually no increase in colonisation success.
Lead author Dr Jenny Hodgson, who developed the computer model used in the study said: “Habitat re-creation close to existing habitat areas may boost the existing populations. But if they need to move wholesale to other areas, then it is more important to provide habitat where there are currently large gaps. We need to strike a balance between short term and long term conservation success.”
Group leader Professor Jane Hill said: “There is a strong relationship between the amount of habitat available to a species, and the rate at which it can spread to new areas. For example, the Comma butterfly which lays its eggs on common nettles has spread through the whole of northern England in recent years, but specialist species seem to be static or declining.”
“Our existing habitats provide the backbone that is vital for species survival both now and in the future, but on their own they are not enough to allow specialist species to keep up with climate change.” co-author Professor Chris Thomas added.
“This result ties in with the findings of a recent report commissioned by Defra and chaired by Sir John Lawton, and should be a stimulus for action at local and national levels.”
