Climate change and networks

Why are habitat networks relevant to climate change?

As climate change takes place, the climatic conditions experienced in different places will change. The precise nature of the changes is still open to debate, but both humans and wildlife will need to adapt to new climates. Habitat networks may provide one mechanism that species can use to follow those changing conditions to a new geographical area. Climate change models predict fairly major shifts from the present climate over time-spans of less than a hundred years, which is much quicker than most earlier changes in the earth's history.

What does it mean for wildlife?

Some species will find themselves in an area where the climate has changed so it's no longer suitable for them - it might be too hot, too wet, too dry or a combination of these factors. Those species will either need to adapt rapidly to that new climate, or move elsewhere to find a climate that's closer to the one that suits them. Each species has a climate envelope - a range of climatic conditions which are suitable for them and an associated area where those conditions are found. This is sometimes also known as a climate space. As the climate changes, their climate envelope will move and species will need to move with it. In northern Europe that's likely to mean shifting northwards or to a higher altitude.  

Those species which are very slow dispersers may not be able to move fast enough to keep pace with climate change (e.g. the willow tit (Parus montanus) which may need to move northwards from southern England, but is a species which rarely travels significant distances). Other plants and animals may be able to disperse more quickly, but they will still need to disperse through the surrounding land area. If they are currently surviving in small isolated habitat patches, and they are surrounded by a hostile matrix between those patches, large scale dispersal is going to be impossible.

How can habitat networks help?

Habitat networks that link together separate patches of habitat could potentially provide a way for some species to disperse following their shifting climate envelope. This is particularly important if climate change is, as it now appears, inevitable, meaning that many species must migrate, adapt or die. By creating habitat networks now and enabling species to move elsewhere, we may be able to provide some species with an opportunity to respond to a changing climate.

However, habitat networks aren't going to be the solution to all our climate change problems. Some habitats (e.g. mature broadleaved woodland) take so long to develop that by the time an effective habitat network is in place, those species that need it may have already become extinct in the local area.

In some cases it may be more important to strengthen and enhance core areas so that they can effectively support vulnerable species, even in a changed climate. For example, capercaillie (Tetrao urogallus) is predicted to lose a large proportion of its climate space in Scotland. That means that improving any existing capercaillie habitat is vital to give the species the best chance of surviving in the future. We can't predict whether or not that will be enough to enable them to survive in a changed climate, but it should help to improve their chances.