An insight into the plants, butterflies and moths at Wheal Jane
For many years Wheal Jane Group have allocated an area of land on the site for the use by the Cornwall Butterfly and Moth Society to study and maintain the vegetation to encourage various species. They have also actively been monitoring the Wheal Jane Limited site for twelve years and carry out annual surveys of the site’s butterflies and moths.
The Wheal Jane site is good example of an actively managed brownfield site where many plants and insects can thrive. This is in contrast with “wildlife sites” which are very often overgrown and neglected. “Rewilding” is the trendy name for this form of wildlife management but it normally results in the land becoming covered in scrub, long grass and eventually trees. This is fine if the goal is to create woodland but it is at the expense of flowers, bees, butterflies and other insects.
Wheal Jane’s site is valuable for wildlife because of rotational disturbance around the banks of the dam. Large diggers are used to scrape off and flail the vigorous vegetation covering the walls of the dam. This is necessary to avoid roots of trees and shrubs from damaging the exterior structure, which is part of the necessary ongoing maintenance and management of this unique pollution prevention project known as the Clemows Valley Tailings Dam. Performing this important work annually, creates bare patches of ground ideal for the plants to flourish, which are used by butterflies and moths. Plants such as Common Birds-foot Trefoil can only thrive in short vegetation or bare patches of ground. If vigorous grasses, scrub and trees are allowed to grow the short flowering plants are smothered and die. This takes away the food for the caterpillars and they die out. It also takes away the flowers used by bees, butterflies and other insects which need nectar.
The photograph below shows areas where butterflies can feast on carpets of yellow flowering Birds-foot Trefoil and other areas which are becoming dominated by tall scrub.
The area in the middle of this photograph taken at Wheal Jane is where the Birds-foot Trefoil is growing and where Silver-studded Blue butterflies are breeding. The area to the right doesn’t contain any flowers and the area to the left will soon be too overgrown. The Birds-foot Trefoil plants are used by many other butterflies and moths including the Dingy Skipper, Common Blue, Five-spot Burnet moth and the Six-spot Burnet moth. The adult butterflies and moths drink nectar from the flowers and the caterpillars eat the leaves.
This is a photograph of the nationally rare day flying Five-spot Burnet moth obtaining nectar from the flowers of Birds-foot Trefoil. The plant is also used by the common Six-spot Burnet moth which has an extra red spot on each wing.
