Climate change and urbanisation are having noticeable effects on long-term trait changes in European birds, a study has found.
About half of the changes in traits seen in recent decades can be attributed to rising mean temperatures, the findings published in the Proceedings of the National Academy of Sciences suggest.
Climate change is probably the largest factor, the study found, but non-temperature factors, such as urbanisation, are also playing a role.
Researchers studied the long-term data sets on the traits of 60 European bird species, including egg laying date, offspring number and body condition.
“We show that in European birds global warming was likely the single most important contributor to temporal trends in laying date, body condition, and offspring number,” the report said.
“However, non-temperature factors were also important and acted in the same direction, implying that attributing temporal trends solely to rising temperatures overestimates the impact of climate warming.
“Differences among species in the amount of trait change were predominantly determined by these non-temperature effects, suggesting that species differences are not due to variation in sensitivity to temperature.”
Across species, approximately half of the trait changes could be attributed to rising mean temperature, suggesting increasing temperatures are probably the single most-important factor, the report found.
The non-temperature factors were able to explain most of the variations in trait changes.