Original article by Pam Berry, Environmental Change Institute Read about the challenges posed to conservationists as species adapt to changing climatic conditions in unique ways.

Introduction

Recent work has highlighted the impact that climate change is likely to have on the distribution of plants and animals. The research has raised fundamental questions about the role of conservation under rapid climate change.

Author Pam Berry of Oxford University's Environmental Change Institute models the impacts of climate change on UK plants and animals.

Species with a southern distribution in Britain, such as the silver-studded blue butterfly, should be able to expand their range northwards. It has been extinct in Lincolnshire since 1945. The picture is with the permission of Lincolnshire Wildlife Trust.

Sections in this article

• Climate changes

• Habitats move

• Conservation questions

• Where next?

Climate changes

Climate change has fascinated and affected people for centuries and the present is no exception. What is different today is that we are able to use the output of global climate models to try and predict the future. Much of the work of Oxford University's Environmental Change Institute (ECI) uses future climate predictions to look at the impacts of climate change on the natural environment. Clearly there is a degree of uncertainty in all predictions of the future, but as researchers, we do our best to understand how changes in climate affect plants and animals.

Some species will need to adjust where they live in response to such a warming. There is already evidence from work done in Oxford University's Department of Zoology that since 1970 great tits in Wytham Woods have been laying their eggs earlier and that this is due to increasing spring temperature.

Past evidence of species' response to changing climates has shown that species react in particular ways and we anticipate that future changes will be species specific too. Mathematical modelling work at the ECI supports this view. It has helped identify three major issues that conservationists will need to take into account.

First, plant species vary in how easily they can cope with climate change. For some with widespread distributions across the nation, such as common grasses and flowers - climate change is unlikely to present a problem. Common species might maintain their widespread abundance, or might even expand.

Plants with a restricted distribution will progressively lose suitable climate space, and face an uncertain future. Climate space is the area where a species can live because the climate is suitable. For instance, Arctic-Alpine plants such as dwarf willow and trailing azalea are found in the relatively cold and wet upland areas in the north of Britain. Further north in the arctic or at higher altitudes in the Alps, dwarf willow is common and abundant because it is comfortably within its preferred climate space, not at the edge of its space as it is in Britain. It has nowhere to move if the British climate becomes too mild.

As the UK climate gets warmer, plants with a northern and highland distribution, such as dwarf willow, have nowhere to migrate. The picture is reproduced with permission of Dick Vuijk of Wageningen and his Flora of Iceland web site.

Habitats move

For example, if traditional oak woodland species such as bluebell, wood anemone and wood violet are going to respond differently to climate change and move at different speeds to different areas, their future distributions may not overlap. What then will constitute typical British oak woodland?

Species that share the same climate space may interact with each other differently, and so the characteristic mix of plants, and the insects that feed on those plants, may change.

Third, will species actually be able to move to a more suitable climate space in the future? This depends on the dispersal ability of the species and the availability of suitable habitat in which to grow.

Many plant species normally disperse comparatively short distances each year and so migration to new areas is going to be a slow business. This means that they are unlikely to fill their suitable climate space in the rapid time-scales that are predicted for temperature change.

In addition, species have other environmental requirements besides climate space. For example, chalk grassland species from southern England, such as the Pasque flower and Lizard orchid, need to find suitable calcareous habitat. Many plants are also dependent on geology and soil type, requiring longer dispersal distances for suitable habitat.

Conservation questions

Climate change poses several interesting challenges for conservation and the role of conservationists. If a species is of conservation interest and under pressure from climate change, should conservationists intervene to help it on its way to new habitats? How much effort should we put into trying to help a species that will become prone to extinction?

Can nature conservationists preserve species that are effectively extinct because of a warming climate? Oblong woodsia is a rare fern that has an English Nature Species Recovery Programme dedicated to its survival. Image is reproduced with permission of Lorne Gill and the UK Biodiversity Action Plan web site.

In National Nature Reserves, there is a legal obligation to maintain or enhance the species and habitats. However, will the species still be there and will the habitats still be the ones we set out to conserve? If species have gone and the habitat changed, then the reserves will be redundant in terms of their original objectives. Does this mean that some Nature Reserves will be abandoned in the future?

The answer has to be no. Habitats are unlikely to lose all their "interesting" species, only those for whom they are no longer suitable sites. However, this may well include a disproportionate number of species of conservation importance. For species that are starting to be affected by climate change, sympathetic management may help to relieve some of the stress.

In addition, the reserves will continue to provide a habitat, perhaps for species from other areas that are trying to migrate to their climate space. The difficulty lies in the legal obligation attached to reserves to maintain the designated species and habitats in situ.

Future conservation legislation and policy must be flexible to allow for this dynamic future and escape from a static view of conservation in perpetuity.

Future change is inevitable as the environment is in a constant state of flux. It should not be seen as a threat, but rather as an opportunity to observe environmental change in action. The challenge is whether to let nature take its course and risk losing species locally or nationally, or whether to intervene to maintain the status quo of species and their habitats.

We know that species will adjust their abundance and distribution as they respond to the changing climate conditions. Some species will take advantage of the new conditions, while others become stressed and disappear from an area. It is unlikely that conservationists will sit back and do nothing.

Conservation has an interesting challenge ahead. The first is how to identify species and habitats at risk from climate change, and the second is and how to devise and implement the best policies for ensuring that biodiversity continues into the future.

Many of the ideas for this article are based on research done in the ECI on the RegIS and MONARCH projects, although the views expressed are entirely my own.

Where next?

On ClimateX.org

‘Swallows linger longer' is an article about the Woodland Trust's public programme to record changes in flowering times across the nation, as expected with a changing climate and seasons. ‘A Butterfly's Map of Climate Change' describes how butterflies provide us with important evidence of changes to our climate.

Away from this site

BBC Radio 4's 'Costing the Earth' featured English Nature's MONARCH project, that investigates the impact of climate change on Britain's plants and animals.

Click here to listen to 'Costing the Earth.' Your PC will need to have audio capability (speakers and a soundcard) and have Realplayer installed. Here you can download a free version of Realplayer.

There is a full summary of the MONARCH project. Also see the

English Nature Species Recovery Programme and the UK Biodiversity Action Plans