The term rewilding was first defined by the conservation biologist Michael Soule in the mid-1990s to describe “the scientific argument for restoring big wilderness based on the regulatory roles of large predators”. Reintroducing missing large carnivores to control herbivore numbers is definitely an important part of rewilding, but it is much more than just that. Nowadays, the definition has come to encompass the whole process of returning ecosystems to a state of ecological health and dynamic balance, making them self-sustaining, without the need for ongoing human management.
Today, few areas of the world are truly wild, and many ecosystems that appear healthy on the surface are not. From African rainforests stripped of primates for the bushmeat trade to the bleached and lifeless coral reefs of the tropical seas, many of the world’s once healthy and diverse ecosystems are now ecological deserts.
Scotland is no exception. Long-term deforestation and overgrazing by excessive numbers of deer and sheep has left the land naked and eroded. There is wildlife, but the numbers are very out of balance and many species are missing altogether. Even woodlands that do survive often consist only of birch, a short-lived pioneer species. In a healthy ecosystem, these trees would gradually be replaced, through the process of succession, by longer-lived species such as Scots pine and oak. The fact that so many Highland birchwoods have become derelict highlights the absence of this key process today.
But how to go about re-instating an entire ecosystem? In the Highlands, it must begin with the restoration of healthy vegetation communities. Over the last few years, considerable efforts have been made to restore and expand native forests, through the use of either fenced exclosures, where deer and sheep are completely absent, or by reducing deer numbers through culling. The results of this are apparent in many sites, with a new generation of trees becoming established, and a healthy, vigorous growth of understorey plants such as blaeberry.
As healthy vegetation communities become re-established, further elements of ecosystem recovery take place spontaneously. Young trees and plants attract insects, whose larvae feed on the leaves, and are, in turn, food for birds. Those transport seeds in their gut, depositing them in their droppings, where they grow, adding to the recovery of the vegetation. Increased populations of birds and small mammals will support raptors and terrestrial predators, such as pine martens, foxes and wildcats.
By this stage, the rewilding process is well underway, but a very important further step is still required, for a return to full ecosystem health and ongoing sustainability. The reinstatement of missing species is critical, from wood ants (which have a short dispersal distance, and therefore are missing from many isolated woodlands), to apex predators such as the Eurasian lynx and wolf, which play a crucial top-down regulatory role in ecosystems.
While the reintroduction of the wolf is often proposed as a means of reducing the excessive numbers of red deer in the Highlands, the main impact of their return would likely be their role in disturbing herbivore populations, causing the animals to move more frequently, so that their grazing is less concentrated in specific areas. Lynx would play a similar role with roe deer. Reinstating this missing ecological process of natural disturbance (which also includes fire, windthrow and floods) is a key step.
The re-establishment of healthy populations of raptors such as the sea eagle, osprey and red kite are success stories of rewilding in the Highlands, and the trial reintroduction of European beavers at Knapdale in Argyll is an important step forward too. As a keystone species in freshwater ecosystems, the beavers are already demonstrating tangible benefits for other species. If the trial is deemed a success and beavers are fully re-introduced, further re-wilding will occur spontaneously. The beavers will dam ponds and fell riverside trees, creating habitats for a whole range of species: butterflies and dragonflies will move in, feeding on the insects that thrive in the oxygenated water, fish will spawn in newly created pools, and these in turn will feed otters, frogs and kingfishers.
Rewilding runs directly counter to human attempts to control nature. We need to step back from the existing imperative of society to utilise every part of the world for our material gain, and let nature prevail in some areas once again.
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