Rewilding Brownsea Island
Rewilding, as a technique for increasing biodiversity, is a hot topic.
Rather than relying on human activities, such as coppicing, hay making or heather burning (all mainstays of the UK conservation sector), to maintain a habitat in what is perceived to be 'good' condition for wildlife, rewilding allows natural processes to govern the outome.
Wolf reintroduction to Yellowstone National Park is often cited as a successful example. When wolves were absent, having been hunted to extinction, deer and elk grazed the river banks of vegetation stopping beavers from building dams. Coyotes became the top predators, dramatically reducing vole and lemming populations. Bald eagles suffered from a lack of carrion.
On their reintroduction, the natural balance was restored. The plants by the rivers recovered, beavers built dams once more - encouring fish and invertebrates to flourish, carrion feeders like the eagles, ravens and bears increased in number.
And it's not just in the USA where rewilding is being promoted. At the Kneep Estate in Sussex, the owners have done away with traditional farming, and are rewilding. They have allowed natural vegetation to grow, only kept in check with traditional livestock breeds, similar to the aurochs, wild boars and deer that would have roamed the countryside. This system has created a haven for, among others, nightingales, turtle doves and purple emporer butterflies - all species that are struggling in the wider countryside.
On a smaller scale, conservationists are working on projects to reintroduce pine martens to control grey squirrels, and beavers to create dams which slow water flow and encourage a wider variety of invertebrates and plants.
But the concept of rewilding isn't new. On a recent visit to Brownsea Island in Poole Harbour, my attention was drawn to a panel in the visitor centre, describing how a previous owner, Mary Bonham-Christie, kicked all of the residents off the island in the 1930s. Despite being nicknamed the 'Demon of Brownsea' by locals, red squirrels and other wildlife apparently flourished, but so did the rhododendron which had been intoduced years before in the formal gardens.
And I think that this could be a problem for future rewilding schemes. Non-native invasive species, like rhododendron, do not have a natural way to be kept in check. In the UK, our once complex ecosystems are so damaged that rewilding may be impossible without significant human intervention.
But that is no reason for not trying. At Brownsea, years of effort by staff and volunteers have significantly reduced the amount of rhododendron. Rewilding is essential on some of our uplands which are denuded of trees by excessive sheep grazing, leading to massive soil erosion and increased flooding.
Decades of environmental damage cannot be easily undone and rewildling is going to have to play a major part.