inspiration
When we talk about ecosystems, it’s often in generalities – the reliance of species on one another for survival. On a more micro level, this plays out in nature in a very literal way. Ecosystems in balance allow all species to thrive, and when something, even small, is removed, it creates discord and breaks the links of the chain. The same applies in reverse: nurturing a native species in the process of rewilding a landscape can restore health to the whole system. As far as a definition goes, a keystone species is an organism that plays a particularly large role in its ecosystem (sometimes disproportionate to its own size), helping to maintain the integrity of its structure. The removal of a keystone species causes a knock-on of negative changes, often decreasing biodiversity, and can even lead to
collapse. Ecologist Robert T Paine, who coined the term in 1969, gives examples that act ‘as predators, ecosystem engineers, or mutualists to keep their habitats healthy’. The much-cited story of the restoration of wolves to Yellowstone in the 1990s gives colour to this theory. What followed their reintroduction seemed nothing short of miraculous, but really, was simply the system recovering. Their presence led to a reduction in elk overgrazing, which in turn allowed vegetation like willows and aspens to recover. This recovery of vegetation then created better habitats for other species, such as beavers and songbirds, and even influenced the physical landscape by reducing river erosion and stabilising riverbanks. This is an example of a ‘trophic cascade’.
Previous spread Elephants, on land and water, use their might to shape the terrain. Left It’s not just clear paths and sustenance that keystone species provide, but shelter too. Above Hippos too, thanks to their size and strength, create channels for water to flow.
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