Restoring and joining up habitat is the way to save threatened butterflies and moths from becoming extinct, according to a new report by a specialist charity.
Butterfly Conservation’s blueprint for the species’ survival, out last week, provides evidence for the first time that “landscape-scale” conservation projects have worked, reversing the fate of threatened species.
It found projects focused on a single butterfly or moth benefit other species and maintaining existing high-quality habitat is more cost effective in the long run than restoring badly degraded sites.
And it highlighted the importance of working with partners and volunteers.
The charity’s east of Scotland branch chairman, Barry Prater, said: “This report is a very good one. I’m particularly struck by the huge differences in habitat which can be brought about by relatively simple measures.
“The principles of the landscape-scale approach certainly apply here in the Borders, but our important habitats are often very different from many of those covered in the report.”
“Despite our sparse population, there is an active and growing group of volunteers willing to do the survey work and other things which increase our knowledge and also spread the word about the importance of butterflies and moths in the web of life, and as crucial indicators of the health of the environment. So we are good at this. There is much more work to do with landowners and managers, though.”
Small blues, a priority species for conservation at national level, are found in just two colonies along the Berwickshire coast, despite the host plant for its eggs, kidney vetch, covering large expanses of the coastal cliffs.
Mr Prater said it was a case where landscape scale conservation – making sure the right habitat is maintained while ensuring there is good connectivity between patches of habitat – could work.
“This is especially important for species which are dependant on just a single caterpillar food plant. If the colony is isolated because there are stretches of inhospitable land around, it is in a precarious position; however, if there are good corridors connecting the patches of suitable habitat then it will be able move between these,” he said.
Volunteers started charting the extent of kidney vetch along the coast, as well as searching for the small blue in the summer.
“If the project shows that connectivity between the remaining colonies and nearby suitable areas is the problem, then it may be possible to link up patches of kdney vetch by planting some and thereby lure the butterfly to strike out to new areas, ” said Mr Prater.
Another Borders butterfly which could benefit from the landscape-scale approach is the green hairstreak, he said.
“Local volunteers have contributed greatly to expanding our knowledge of green hairstreak colonies – the stronghold appears to be amongst the forested hills to the north and west of Peebles, but it also has a number of scattered colonies throughout Roxburghshire.”
Recent Borders arrivals, such as the small skipper, speckled wood and comma, are doing well he said, probably because they use widespread, common plants, such as nettles and grasses, for egg-laying.
But he was concerned about the large heath (pictured top of page).
He said: “It is confined to just a handful of boggy, often moorland sites, so drainage and plantations are ever-present threats.”
But “because of the relative remoteness and trickiness of its habitats, we probably don’t ever have an up-to-date picture of its status, which of course militates against taking actions to conserve it.”
It can been seen at Din Moss, near Kelso.
Butterflies are the most threatened wildlife group, with more than three-quarters of Britain’s 57 resident species declining and over 40 percent listed as priorities for conservation. More than 80 moth species are also at risk.
Most threatened species are now confined to small patches of habitat, isolated within the intensively managed countryside.
Butterfly Conservation has been using a landscape-scale approach to conserve certain areas for over a decade.