Our conservation efforts need to be more effective in identifying and protecting bird species that are at risk due to climate change, according to a study published in the Journal of Biogeography. The authors emphasise that we need to understand better the range of specific conditions these animals need to thrive.
The team from the University of East Anglia (UEA) in the UK assessed the relationship between the extreme climatic conditions that species can survive—known as climatic niche breadth—and the likelihood of the number of birds declining in response to climate change.
Results showed that species that tolerate a wider range of climate conditions are less likely to decline or even increase compared to those with narrower climatic preferences. The authors believe these findings provide valuable information regarding how climatic niche breadth is an important factor in predicting different species’ vulnerability to climate change.
The authors suggest adding data about each species’ climatic niches into climate change models is a good way to design better conservation strategies. Variations in climatic conditions within a species range can provide greater detail to understand their resilience to factors that affect their population.
“Deciding which species are more at risk isn’t straightforward, and species may be declining for a range of reasons. Rare species and those that have smaller distributions are more likely to be vulnerable to climate change. This study has shown that birds that are more widespread, such as the house sparrow and the common starling, can also face threats to their populations. Species, whether rare or widespread, with narrower climatic niches may be more susceptible to the rapid changes brought on by climate change compared to those with broader niches, and this may be one of the underlying reasons behind the population declines observed,” said lead author Karolina Zalewska. “Our results emphasise the importance of understanding and incorporating the level of exposure to climatic variability when assessing vulnerability to climate change and long-term population declines.”
Climate change is a major threat to global biodiversity, but researchers know that the extent of this threat is not the same for all species. This is due to differences in life histories and exposure to environmental change, with some climatic conditions having a bigger impact than others.
While species with broad geographic distributions are expected to be more resilient to environmental change, recent population declines suggest other factors are also involved. This study shows that the breadth of climatic conditions a species can tolerate has a major influence on its resilience to climate change.
“Faced with the challenges of the global biodiversity crisis and climate change, the rapid assessment of species vulnerability to environmental change has become of paramount importance to address priorities for conservation. As climate change accelerates, our study highlights the need to prioritise species that are most at risk due to their more restricted environmental requirements,” said Prof Aldina Franco from the School of Environmental Sciences.
For this study, the authors used data from the Pan-European Common Bird Monitoring Scheme for population trends of 159 European breeding bird species across 29 European countries. Thirty years of climate data for each species’ breeding ranges were used to create representations of their climatic niches and produce a new index of climatic niche breadth that accounts for each species’ distribution area. This analysis also included the species’ diet, primary habitat type, migratory status, and average body mass. All this information was used to explore how these variables influence the long-term population trends.
Results showed that, of all the species included in this study, 58 had a decreasing population trend, 68 species were stable, and 33 were increasing. What’s more, species associated with farmland habitats, both in the UK and wider European area, such as the corn bunting or skylark, were more likely to be declining. In contrast, those able to tolerate more human-modified environments, including blackbirds and blue tits, were more likely to experience increasing population trends.
“These findings can help us understand the threats associated with climate change and allow for rapid assessment of the importance of climatic factors on population trends, providing an invaluable tool for targeting species conservation,” added Miss Zalewska. “In particular, we show that the climatic niche breadth to range area index can help predict which species may be more vulnerable to population declines.”
Zalewska K, Gilroy J, Catry I, Atkinson P, Klvaňová P, Franco A (2025) European Breeding Bird Declines Associated With Narrower Climatic Niches. Journal of Biogeography, https://doi.org/10.1111/jbi.15127