Butterflywatch: rare high brown fritillary thrives on Dartmoor

Species declined by 96% since 1950s but this summer numbers are strong in south-west England
2022-08-31 05:00

There always seems to be one British butterfly species in a death spiral towards extinction. The Duke of Burgundy was on the brink but targeted conservation action has brought a surge in numbers over recent seasons.

Over the last decade, the disappearance of the high brown fritillary has most worried butterfly lovers. It experienced a 96% decline since the 1950s – a once-common wood-edge butterfly turned into a rare species.

More worryingly, the patient seemed not to respond to emergency medicine: despite focused conservation work at its stronghold around Morecambe Bay, populations there have continued to decline.

So this summer’s news from the south-west is particularly welcome with experts recording strong numbers on Dartmoor. Here, farmers are working alongside the national park, the National Trust, Butterfly Conservation and others to manage bracken habitats where the high brown caterpillar’s food plant, common dog-violet, thrives.

The high brown has responded well in recent summers on its remaining sites in Exmoor and south Wales too, its threatened status downgraded from “critically endangered” to “endangered” in the 2022 red list of at-risk butterflies.

It shows we can effectively administer emergency medicine during an extinction crisis. But the decline of common butterflies and other insects is a reminder that we are still failing to provide good public health for our wider natural world.