Climate warming damages DNA of endangered songbirds, study finds

Climate change is likely to increase hot and dry conditions, and repercussions of such sublethal effects on young birds can imperil population persistence. Credits: Dr Niki Teunissen, Monash University and the Australian Wildlife Conservancy.

A new study led by Monash University scientists found DNA damage in endangered Purple-Crowned Fairy Wren nestlings exposed to hot and dry conditions during their first days of life.

This result, published today in Proceedings of the National Academy of Sciences (PNAS), has implications for population persistence under climate warming through an associated reduction in lifespan.

As Dr Justin Eastwood from Monash University’s School of Biological Sciences said the combination of hot and dry conditions was related to the shortening of a DNA region known as telomeres which function to maintain chromosome integrity. When they become too short to do their job, they accelerate the ageing process.

The result of shorter telomeres is that nestlings have a reduced capacity to deal with further DNA damage, meaning they age earlier and die younger.

“Our long-term study has followed the birds from hatching and observed everything we could about their reproductive behaviour until death,” Dr Eastwood said.

“This detailed study has led to the discovery that nestling telomere length is a biomarker of lifespan and the number of offspring they have over their lifetime, ” said project leader Professor Anne Peters, also from the School of Biological Sciences.

The endangered, purple-crowned fairy-wren population studied is located at the Australian Wildlife Conservancy’s Mornington Wildlife Sanctuary in the Kimberley, Western Australia.

These findings are concerning for this endangered population and the conservation efforts of Professor Peters and her team because climate warming is likely to increase the number of nestlings exposed to hotter and drier conditions which can eventually depress population reproduction as indicated through their damaged telomeres.

The team subsequently modelled different climate scenarios and how the population could theoretically escape the effects of climate warming on lifespan and subsequently, maintain population viability.

“We found that even under relatively mild climate warming scenarios that the non-lethal effects on nestling telomere length alone could result in population decline,” Dr Eastwood said.

“But in contrast, the math also showed that breeding during wetter conditions or evolving longer telomeres could possibly mitigate the effect,”.

Critically, the team note that these escape measures are still hypothetical and are increasingly unlikely given the speed at which the climate is warming.

The authors also highlight the need to incorporate these hidden long-term impacts of climate change when predicting species decline in addition to the obvious drivers of extinction such as habitat loss and lethal heat waves causing mortality events.

This research was funded by the Australian Research Council’s (ARC’s) Discovery Project scheme.

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