Hidden amidst an unruly wilderness, just a stone’s throw from the bucket and spade charm of Lyme Regis, one of the UK’s rarest butterflies is taking advantage of a disaster zone.
The dramatic tumbledown coast linking West Dorset to East Devon is a stronghold of the Wood White, one of our daintiest and most rapidly declining butterflies.Tiny, with a floppy, feeble flight that suggests an imminent stall, the Wood White is a delicate sprite that graces late spring and early summer woodlands.
Achingly rare, there are now less than 70 Wood White colonies left in the UK. But in the undercliffs and landslips defining the coast between Lyme Regis and Sidmouth, the butterfly is not only thriving but is also behaving very differently from its northern relatives. Here the butterfly has left the woods and headed for the seaside.
This stretch of Jurassic Coast is one of the largest and most active coastal landslip systems in Western Europe. Its ever-changing, shape-shifting nature has created a spectacular tangle of woods, collapsed bare earth and scrub. Wood White colonies here are the only place in the UK where the butterfly is found at coastal sites. But why has the butterfly forsaken the woods to head into a geological disaster zone?
Dr Sam Ellis, Butterfly Conservation Director of Conservation and Regions, and a man who claims to have found a dead Wood White in a Lyme tea room, explains: “It’s the very instability of the Undercliff which maintains the Wood White on our coast.
“Its caterpillars feed on various species of vetch and trefoils that thrive in the bare open ground created by a landscape in constant flux. The slips and falls leave patches of open ground enabling the plants to thrive. If conditions were more settled, the open vegetation needed by the butterfly would become swamped by scrub.”
But the unforgiving nature of the Undercliff can be too much even for the Wood White. A colony at Ware near Lyme was decimated by a huge landslip in 2013.
A walk along the coast path between Lyme and Seaton from May through to June has a good chance of revealing a glimpse of the wandering Wood White. There are several colonies en-route with particular hotspots near Culverhole, Goat Island and Haven Cliff. The butterfly may even be spreading east of Lyme with occasional sightings at Black Ven.
This rapidly declining species used to be found across much of southern England and into eastern Wales. Away from the Jurassic Coast, the Wood White's strongholds are now the woods of the West Midlands and Northamptonshire.
Liam Creedon is Head of Media at Butterfly Conservation. Read his work on Twitter @liamcreedon