St Helena’s unique Spiky Yellow Woodlouse species is struggling to survive, a comment by visiting expert Dr Roger Key has suggested.
The plight of the “amazing little creature” was noted back in 2003, when Dr Rebecca Cairns-Wicks of St Helena National Trust said it was “not as common as it was just ten years ago”.
Dr Key referred to the unusual tree-climbing woodlouse in an interview, after several weeks of surveys of “all the creepy-crawlies that St Helena is so special for”.
He told SAMS radio that a number of endemic invertebrates on the island appeared to be going the way of the giant earwig, which is listed as critically endangered but may now be extinct.
“All the way through Britain and all its overseas territories,” he said, “half of all the bugs that only occur in one place are actually in St Helena.
“There are 400 odd species that only occur in St Helena. Unfortunately, that number’s going down.
“Everybody’s heard of the giant earwig, which was last seen in the Sixties and it was four inches long, so it probably isn’t around any longer.
“You also have things like the Spiky Yellow Woodlouse, which is still here, just, but is only hanging on by the skin of its feet.”
The giant earwig is the only St Helena invertebrate to feature on the global “red list” of endangered species – along with the wirebird and several species of fish.
He said that fellow scientist Dr David Price would be working out the rarity of various species and seeking international help conserving them, during a two-year contract on the island.
That may mean finding a balance between the needs of invertebrates and other sensitive species, said Dr Key.
“Sometimes doing the right things for the plants and the birds might be a little bit different to what you do for the invertebrates, so it’s working out what works for everything.”
In a 2003 report for the St Helena National Trust newsletter, Dr Cairns-Wicks described the Spiky Yellow Woodlouse’s unusual liking for climbing the branches of tree ferns and other endemics.
“It has been called a ‘living’ fossil because it is an ancient species,” she said. “It has distant relatives as far apart as South America, Madagascar, South Africa and Australia.
“It is because it is so unique and ‘ancient’ that it is highly important, and it could help in the study of how today’s continents came to be formed.
“Unfortunately, however, the Spiky Yellow Woodlouse has only ever been recorded from High Peak in recent times. Only a tiny fragment of tree-fern thicket and cabbage trees survive at High Peak, and they are heavily invaded by flax, fuchsia, bilberry and other invasive plant species.
“Occasional observation suggests that the Spiky Yellow Woodlouse is not as common as it was just 10 years ago.”
The Trust has since begun a programme to revive the cloud forest along High Peak and the ridges above Broad Bottom by removing invasive species and planting endemics.
Spiky Yellow Woodlouse – St Helena National Trust newsletter