Birds are tracking climate warming, but not fast enough

Area of Science:

• Ecology
• Climate Change Biology
• Biodiversity Research

Background:

• Species range shifts are observed responses to global warming.
• The pace of these shifts relative to climate warming remains uncertain and difficult to quantify.

Purpose of the Study:

• To develop a framework for measuring changes in community composition in response to climate warming.
• To quantify the lag between species' range shifts and temperature increases.

Main Methods:

• Developed a community temperature index (CTI) to assess the balance of low- and high-temperature dwelling species in an assemblage.
• Analyzed data from the French breeding bird survey over two decades.
• Compared the northward shift in bird community composition (CTI) with the northward shift in temperature.

Main Results:

• A significant increase in CTI was observed, indicating birds are tracking climate warming.
• Bird community composition shifted 91 km northward, while temperature increased by 273 km northward.
• Bird communities are lagging approximately 182 km behind temperature increases.

Conclusions:

• The developed CTI framework effectively measures community composition changes in response to climate warming.
• Bird communities are not shifting fast enough to keep pace with rapid climate warming.
• The method is applicable to various taxa and can be used to compare delays across different groups and land-use contexts.