Some birds are more at risk from climate change than others

Efforts to protect birds from the growing impacts of climate change may be missing a key piece of the puzzle. According to new research, understanding the specific climate conditions that birds need to survive – known as their climatic niche breadth – could be crucial for identifying which species are at greatest risk.

Scientists from the University of East Anglia analyzed data from 159 European bird species to explore how a species’ tolerance to different temperatures and rainfall patterns relates to its population trends.

The researchers analyzed four decades of bird population data across 29 countries, combined with 30 years of climate information, to measure how adaptable each species is to a variety of conditions within its habitat.

Even common birds face climate risks

It’s widely assumed that rare birds or those with small geographic ranges are most vulnerable to climate change. However, new findings suggest that a bird’s vulnerability isn’t solely about how widespread it is. What seems to matter more is how broad – or narrow – the range of climate conditions a species can handle is.

“Deciding which species are more at risk isn’t straight forward, and species may be declining for a range of reasons,” said lead author Karolina Zalewska, a postgraduate researcher in UEA’s School of Environmental Sciences.

“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.”

Birds with narrow climate ranges

According to Zalewska, the results emphasize the importance of understanding and incorporating the level of exposure to climatic variability when assessing vulnerability to climate change and long-term population declines.

The study confirmed that a bird’s ability to cope with a variety of climate conditions is strongly linked to its population stability. Even among species with similar geographic ranges, those with narrower climate tolerances were more likely to be in decline.

“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,” said co-author Professor Aldina Franco.

“As climate change accelerates, our study highlights the need to prioritize species that are most at risk due to their more restricted environmental requirements.”

A better way to assess risk

The team used their climate data to develop a new index – climatic niche breadth adjusted for range area – that can help predict which birds are more vulnerable to environmental change. This index, combined with data on diet, body size, primary habitat, and migratory behavior, offers a more complete picture of each species’ resilience.

“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,” said 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.”

Out of the 159 species examined, 58 were found to be declining, 68 remained stable, and 33 were increasing.

Birds that inhabit farmland – such as corn buntings and skylarks – were more likely to be in decline. By contrast, species more comfortable in human-altered landscapes, like blackbirds and blue tits, were faring better.

Conservation through a climate lens

The research offers a way forward for conservation strategies in an era of accelerating climate change.

Instead of relying solely on range size or rarity, conservationists may need to look more closely at how birds respond to different climates across their range.

Recognizing which species are climate-sensitive could make all the difference in keeping their populations from slipping away.

The full study was published in the journal Journal of Biogeography.

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