From: Editor, ENN
Published August 12, 2013 02:50 PM

Age isn't just a number: New research shows song sparrows are affected by climate change differently depending on age

New research at the University of California, Davis, and Point Blue Conservation Science shows that song sparrows experience climate change differently at various ages.


Two studies show the importance of considering the various stages and ages of individuals in a species to best predict not only how climate change could affect a species as a whole, but also why.

"To learn how climate change is expected to affect an individual population, you have to look at demography," said lead author Kristen Dybala, a postdoctoral scholar in the UC Davis Department of Wildlife, Fish and Conservation Biology. "If you don't break it down by these different stages, you get a different understanding that may be misleading, or worse, that's just wrong."

In a study published today in the journal Global Change Biology, climate change had opposite projected effects for adult and juvenile song sparrows in central coastal California. While it is evident that adult survival is sensitive to cold winter weather, warmer, drier winters mean less food for juvenile sparrows during the following summer.

"Before they can get to winter, the juveniles have to survive their first summer, when they're sensitive to how much food is available," said Dybala. "So as winters get warmer, we expect adults and juveniles to respond in opposite directions."

In another recent study of song sparrows published in the journal Ecology, lead author Dybala found that parents provided a buffer against the weather for baby sparrows still dependent on them for food. However, independent juveniles that were newly out on their own were more sensitive to changes in the weather because they lacked the skills and experience of their parents.

While that vulnerability has existed for as long as offspring have been leaving the nest, climate change is expected to exacerbate those already uncertain conditions, Dybala said. This sort of variation in juvenile survival can significantly impact a species' population growth.

The scientists said that this research could be used to inform climate change adaptation plans, help prioritize future research, identify where limited conservation resources could be best spent and help soften the impacts of climate change for individual species.

Read more at the University of California, Davis.

Song sparrow image via Shutterstock.

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