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British butterflies are at risk of being wiped out by farming as conservation measures fail

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British butterflies are at risk of being wiped out by intensive farming as conservation measures are failing to protect some of the country’s rarest species, a study found. 

Species under threat include Duke of Burgundy, the Dingy skipper and the High Brown Fritillary, researchers have warned.

Conservation efforts around the margins of agriculture are not enough to protect all the rare species, they added, which are suffering from pollution and climate change.

The subsidised schemes are instead helping common, more mobile, grassland varieties like the Ringlet and the Meadow brown — even doubling their numbers.

They programmes work by offering financial rewards to those farmers who manage their land in ways that aim to reduce the environmental impacts of agriculture.

Popular options include setting small areas of land aside for butterflies — for example, strips of grass at the edges of crops.

British butterflies are at risk of being wiped out by intensive farming as conservation measures are failing to protect some of the country's rarest species, a study found. Pictured, a male Duke Of Burgundy (Hamearis lucina) butterfly, which is under threat in the UK

British butterflies are at risk of being wiped out by intensive farming as conservation measures are failing to protect some of the country’s rarest species, a study found. Pictured, a male Duke Of Burgundy (Hamearis lucina) butterfly, which is under threat in the UK

‘These kind of set aside schemes help mobile, common butterfly species move across landscapes. But they do not help all species,’ said paper author and biologist Katie Threadgill of the University of York.

‘I would expect something like a Grizzled skipper also to be in the camp of species unlikely to benefit from this management approach.’

In their study, Ms Threadgill and colleagues examined whether these conservation schemes were indeed helping insects — including butterfly populations.

The analysis used ecological models to see if the programmes improved the survival of insects locally and helped them expand across landscapes — as species will need to move in response to climate change.

‘The greatest benefits were seen in species which were either highly mobile or which live in high densities,’ explained Ms Threadgill.

‘High density species which could travel further were already successful expanders regardless — although expansion rates were still improved when set-asides were added.’

‘Overall, the strips did increase rates of range expansion across landscapes by up to 100 percent for some species. But they did not boost long term butterfly survival locally.’

Farmland makes up three-quarters of the UK’s landscape — but recent research has shown that the number of butterflies such as the High Brown Fritillary have more than halved since the year 1990.

Species under threat include Duke of Burgundy, the Dingy skipper (pictured here pollinating a flower) and the High Brown Fritillary, researchers have warned

Species under threat include Duke of Burgundy, the Dingy skipper (pictured here pollinating a flower) and the High Brown Fritillary, researchers have warned

‘Small-scale set-asides have the potential to improve connectivity, which will help some species move to cope with climate change and connect up habitat patches for others,’ said lead author and biologist Jane Hill of the University of York.

But the study concluded that set-asides are unlikely to benefit low dispersal, low density species — which are likely at greater risk from agricultural intensification.

‘Our results suggest small set-aside strips alone are not an appropriate solution for preventing extinctions in the long term, but can provide other benefits,’ said Ms Threadgill.

Increasing intensive farming and habitat fragmentation is reducing biodiversity and the resilience of insects, she added.

The results show that conservation incentives can help combat the problem by boosting the extent to which species are able to traverse landscapes.

'Set aside schemes help mobile, common butterfly species move across landscapes. But they do not help all species,' said paper author and biologist Katie Threadgill of the University of York. Pictured, two High Brown Fritillary butterflies, which are at risk in the UK

‘Set aside schemes help mobile, common butterfly species move across landscapes. But they do not help all species,’ said paper author and biologist Katie Threadgill of the University of York. Pictured, two High Brown Fritillary butterflies, which are at risk in the UK

‘The magnitude of range expansion benefits are not universal across species or landscapes, but can be considerable,’ Ms Threadgill said.

‘Thus, land management activities can have important landscape connectivity co-benefits which should be carefully weighed up in the evaluation of environmental policies and the design of future schemes.’

The annual UK Butterfly Monitoring Scheme published in March found that the insects had bounced back to their best levels for 20 years.

There was an increase in numbers for more than half of species in 2019 compared with 2018.

Conservation efforts around the margins of agriculture are not enough to protect all the rare species, they added, which are suffering from pollution and climate change. The subsidised schemes are instead helping common, more mobile, grassland varieties like the Ringlet and the Meadow brown (pictured) — even doubling their numbers

Conservation efforts around the margins of agriculture are not enough to protect all the rare species, they added, which are suffering from pollution and climate change. The subsidised schemes are instead helping common, more mobile, grassland varieties like the Ringlet and the Meadow brown (pictured) — even doubling their numbers

A warm and wet summer helped butterflies in their younger stages and when they emerged from their cocoons as adults. 

The Marbled White Butterfly had its best year, with its numbers up by two thirds.

However, the Common Blue population dropped by more than half — and it was just one of several species that saw a decline.

Butterfly Conservation associate director of monitoring and research Tom Brereton, however, said that butterfly numbers were still a cause for concern.

‘The results from the 2019 season are really encouraging and provide evidence that the overall rate of decline of butterflies is slowing and for some species being reversed,’ he added.

‘We are really heartened to see a shift in the fortunes of many of our most loved species.’

The full findings of the study were published in the journal Ecography.  

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