Study finds European breeding birds respond only slowly to recent climate change

Over the last 30 years, European breeding birds have shifted their range by, on average, 2.4km per year, according to new research.

However, these changes significantly differed from expectations based on changing climate and land cover during that period.

Based on climate alone, the researchers predicted that the average range shifts by species should have been around 50% faster.

The study used survey data for 378 bird species collected as part of two Europe-wide bird distribution atlases produced by the European Bird Census Council 30 years apart.

The researchers found that local colonisation and extinction events across species ranges were only weakly influenced by the change in climate between the two survey periods.

Instead, they were more influenced by the climatic conditions at the time of the first surveys.

One of the key determinants of whether a new area was colonised or whether a population went extinct was the extent to which the area had other populations of a species close by, which facilitated colonisations and minimised extinctions, presumably by the dispersal of birds from neighbouring areas.

This finding highlights the importance of maintaining networks of local populations to limit extinctions and to make populations more robust to the effects of climate change.

The study findings have been published in the journal Nature Communications.

Joint study-lead Professor Stephen Willis of Durham University said: “Our findings potentially show two intriguing responses to recent climate change. In some areas, ‘colonisation lags’ may result in species being unable to track improving climate, perhaps due to habitat or prey not yet being available in new sites.

“By contrast, fewer extinctions occurring in areas where we predict them to occur might be evidence of ‘extinction debts.’

“Such debts occur when species are committed to eventual extinction due to unfavourable climate, but they nonetheless manage to persist, sometimes for lengthy periods, because key limiting factors, such as their preferred habitat, take some time to alter.”

First joint-author, Dr Christine Howard, added: “The key role of non-climatic factors in altering range changes highlights that climate is just one factor impacting populations of European breeding birds.

Co-author Dr Sergi Herrando, who led on collating data for the second European atlas EBBA2, added: “The work presented here highlights the ways in which coordinated survey data, collected across many countries, can be used to understand the causes of species losses and gains better.

Dr Petr Vorisek, Co-author and coordinator of the atlas added: “The data collection used in this study involved huge numbers of people. The second breeding atlas alone collated data from 120,000 field workers – citizen scientists, permitting a systematic survey of 11 million square kilometres across 48 countries.”

Dr Verena Keller, EBCC Chair and project manager of the second atlas, said: “The high number of co-authors, many of which were instrumental in the preparation of EBBA2, highlights the scientific potential of the continent-wide network of the EBCC.”

Source information

 ‘Local colonisations and extinctions of European birds are poorly explained by changes in climate suitability’, (2023), Christine Howard, Emma-Liina Marjakangas, Alejandra Moran-Ordonez et al. and Lluis Brotons, Aleksi Lehikoinen and Stephen Willis, Nature Communications.