New Indicator of Climate Change’s Impact on Bird Populations

To date, few indicators have been developed that summarise the impacts of climate change on multiple species over large areas of land. Such an indicator is much desired by policy-makers, who want to be able to see the potential impacts of climate change on biodiversity. A new EU-supported study has therefore developed an indicator of climate change’s impact on European birds, which has subsequently been used to report threats to biodiversity.

The climatic impact indicator (CII) was developed by studying 108 of the 124 species in the Pan-European Common Bird Monitoring Scheme. It provides a graphic representation in the form of an index to demonstrate how climate change is affecting biodiversity. When the size of a bird’s population changes in line with predictions, the indicator goes up. The predictions come from a climate envelope model which maps changes in the environment surrounding a certain species or ecosystem under likely climate change. The indicator has been increasing since the 1980s, a pattern which matches rising temperatures in Europe and suggests that climate change is having a growing impact.

Whilst the CII incorporates both positive and negative changes in bird populations, the researchers found that 75 per cent of changes were negative. The species likely to be worst affected by climate change include the Common Snipe (Gallinago gallinago), Meadow Pipit (Anthus pratensis) and Brambling (Fringilla montifringilla), although some species, such as the European Bee-eater (Merops apiaster), are already being observed to benefit.

The CII may be able to inform environmental policy by acting as a biodiversity target, for example if a policy objective was introduced to slow the rate of increase of the CII. Such a target would of course have to recognise time lags in the impact of climate change. Separate CII indicators could nonetheless be prepared for individual countries and groups of birds in the future, as well as for many different species.

Source: Gregory, R.D., Willis, S.G. Jiguet, F. et al. (2009). An indicator of the Impact of Climatic Change on European Bird Populations.
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