Swan populations grow 30 times faster in nature reserves: study

The population of swans rose by six percent in nature reserves and only 0.2 percent outside of them.

The results show that nature reserves could help double the number of whooper swans wintering in the UK by 2030.

Researchers examined 30 years of data on whooper swans at 22 UK sites.

Three of these sites were nature reserves managed by the Wildfowl and Wetlands Trust (WWT).

While these swans had a lower annual probability of breeding they had more opportunities to produce offspring in their lifetime, leading them to reproduce more on average.

Dr. Andrea Soriano-Redondo, from the universities of Exeter and Helsinki, said: “Protected areas are the main tool being used to stem declines in biodiversity, and there is a growing consensus that 30 percent of the planet’s surface should be protected by 2030.

“However, the effectiveness of protected areas is not always clear – especially when species move between protected and non-protected areas throughout their lives.

“Our findings provide strong evidence that nature reserves are hugely beneficial for whooper swans and could dramatically increase their numbers in the UK.”

Whooper swans are also known as common swans and normally spend their winters in the UK and summers in Iceland.

The team observed over 10,000 of these swans.

Dr. Richard Inger, from the Centre for Ecology and Conversation on Exeter’s Penryn Campus in Cornwall, said: “The annual population growth rate inside nature reserves was six per cent, compared to 0.2 percent outside reserves.

“This population boost is not restricted to the nature reserves – it created a higher population density, which led some swans to move to non-protected areas.

“Young swans were most likely to do this, meaning the benefits of nature reserves spill over to other areas too.”

Nature reserves have a range of measures in place to help protect swans.

They include fox fences, supplementary food, managed roosting sites and hunting bans.

Professor Stuart Bearhop, from the University of Exeter, said: “Overall, our study demonstrates the huge benefits of localized protection for highly mobile animal species.

“It also shows that targeted measures during key periods of the life cycle can have disproportionate effects on conservation.”

David Pickett, a Centre & Reserve Manager at WWT Caerlaverock Wetland Centre, added: “This research shows how safe havens for wetland wildlife, like those at WWT Caerlaverock, Welney and Martin Mere, can help a species survive and succeed when their traditional homes are under threat.

“Many wild birds rely on our sites for food and shelter and we are committed to creating and restoring more of these healthy wetland habitats, which the UK has lost so many of in our recent history.”

The study was published in the journal Proceedings of the National Academy of Sciences.