A Thorny Problem For Our Butterflies

Our beloved butterflies — we see 59 species in the UK — are in decline, partly due to lack of habitat and food

- Dareen Rogers

The first butterfly of the year is noted by most in the countryside as one of the heralds of summer. There are 59 species found in the UK on a regular basis. Two of those are non-breeders here, simply common visitors, which are the painted lady and the clouded yellow. Sadly, along with far too many species, our butterflies are in decline with a 52% reduction in abundance in the past 10 years alone. Equally worrying is that the number of sites they are being found at has also reduced by 47% in the same period.

Those facts are bad enough but they come on top of large-scale losses since the mid-1970s. One species named the wall butterfly, mainly found in the north of England and the border country, has declined by almost 80% since that decade and that is a scale of loss that cannot be endured if the species is to survive.

The reasons are many. A large number of butterflies make use of specific plants on which they lay their eggs and their caterpillars then feed on. Many of these plants are part of habitats that are themselves under threat, putting the existence of many other species at risk. Limestone grassland, nurtured for hundreds of years for livestock production, has been ploughed up, in many cases in a vain attempt to grow arable crops.

Ancient woodland

Heathland has reverted to scrub and large areas of ancient woodland have also been lost, or the management of it has been such that the understorey has declined and the food plants of woodland butterflies lost. At times it takes a subtle change in circumstances to alter the balance for these species, and that may be as simple as increased browsing by deer taking out a vegetation layer, or the very opposite, a lack of grazing that leads to plants being smothered by more invasive ones.