Cores Corridors and Keystone Species Scientists believe successful rewilding projects need three things cores corridors and keystone species Cores Every plant and animal needs a specific amount of space food and water to survive A core is a stretch of land large enough to support all forms of life that would exist there naturally in the wild Some creatures like grizzly bears and tigers need huge cores That’s a tall order in a world bustling with people Corridors Corridors are routes that connect cores so wildlife can travel across built-up or unfriendly areas to find food and mates Corridors don’t have to be totally wild but they must be natural enough so that native animals and plants will use them 10 REWILDING Animals use overpasses as corridors to move safely from core to core
Keystone Species In building construction the wedge-shaped block at the top of an arch steadying and locking all the other blocks in place is called the keystone In biology a keystone species is an animal or plant that more than most keeps its habitat or ecosystem in balance Top carnivores such as cougars and wolves are keystone species because their hunting prevents the population of prey animals from getting too large and crowding out others in the habitat Top herbivores such as elephants and beavers are also keystone species because their trampling and dam engineering can change the landscape And people are keystone species too Keystone species affect their whole habitat even parts they don’t have direct contact with Rewilders have to work hard to keep these The cougar is a keystone carnivore that keeps deer numbers in check three elements cores corridors and keystone species in balance That means they have to think carefully about relationships between habitats wildlife and people And they have to adjust to unexpected circumstances modify their plans fail and try again Rewilding is big complex risky and exciting Herds of reindeer top left and African elephants right require vast core areas to find enough food to raise their families WHAT IS REWILDING 11
2 Wild Again The American buffalo is an eco-engineer that tramples grasses and wallows on dry ground As successful keystone carnivores leopards hunt on the grasslands then drag their prey up trees to feed in safety 12 REWILDING REINTRODUCING KEYSTONE SPECIES
A habitat is not fully rewilded unless the all-important keystone species the ones that help keep the environment in balance thrive there As we know large carnivores are keystone species because they eat species further down the food web and keep their numbers in check That may seem harsh but it actually promotes coexistence among all the different species that share a habitat Large herbivores like horses and deer graze the land keeping it from getting overgrown and containing the spread of wildfires Larger herbivores like elephants trample trees and shrubs so that sunlight can reach the soil for seedlings to grow Herbivores are also keystone species when they act as eco-engineers and change the landscape by their dam building or burrowing Eco-engineers promote diversity in a habitat because they open up new homes and food sources for other plants and animals Of course bees hummingbirds and other major pollinators are keystone species too because many plants rely on them to reproduce When a habitat’s pollinators disappear or change so do the plants that grow there and the creatures that need those plants for food or shelter But when it comes to rewilding a keystone species in its habitat sometimes all our efforts fail Rewilders want to know why and what to do next Honeybees provide a critical eco-service by fertilizing plants while collecting pollen for themselves Zoos can help protect and save endangered species from extinction but can zoo animals ever be brought back to live in the wild And what about the creatures that have no habitat to return to are they out of luck or can they be rewilded into a totally new landscape This section looks at stories of why some significant and keystone species start to disappear and what happens when people try to help them live in the wild again Sometimes people’s behavior has to change It takes a lot of hard work but even when our best efforts fail we learn valuable lessons REINTRODUCING KEYSTONE SPECIES WILD AGAIN 13
