From beavers in the UK to bison in the Great Plains, reintroducing keystone species back into their historic ranges significantly benefits and rebalances their ecosystems.
A new study funded by One Earth partnering with RESOLVE, found that restoring just 20 large mammal species could help ecosystem restoration worldwide. By rewilding such species as brown bears, lions, and wild horses, more than 8.5 million square kilometers could once again regain their historical large mammal communities.
Large mammals are vitally important for maintaining healthy ecosystems on our planet. Acting as landscape engineers, they shape the composition of plant life and wildlife in their habitats.
Various projects are underway to bring back these vital species, and many have already reaped the benefits. Here are six successful rewilding stories from around the globe.
1. Eurasian beavers in the UK
Once, the Eurasian beaver flourished throughout Europe and Asia but was heavily hunted for its fur and meat. By the sixteenth century, they became extinct in many countries, including the UK.
Beginning in 2021 and continuing into 2022, beavers were reintroduced in Dorset, Derbyshire, the Isle of Wight, Nottinghamshire, Montgomeryshire, and South Downs. The severe weather impacts of climate change have hit many of these areas hard with extreme rainfall, and beaver dams decrease the effects of floods by up to 60% by reducing water flow.
The same mechanism is also a solution for droughts, as beaver dams create water reservoirs. In addition, beaver dams also capture CO2 as the wetlands they make cultivate new plant growth in the surrounding area and form a carbon sink.
2. Blue wildebeest in the Serengeti
Essential to keeping the endless plains of the Serengeti a carbon sink is the blue wildebeest. Yet, in the mid-20th century, their population was decimated to just 300,000 due to viruses from livestock.
Ground vegetation began to overpopulate, eventually leading to wildfires that destroyed 80% of the ecosystem annually. This led to a net release of carbon dioxide into the atmosphere, turning the Serengeti into a producer of greenhouse gases.
The landscape was brought back into balance when disease management efforts helped the wildebeest population recover to their historic levels of over 1.5 million. In less than a decade, the Serengeti was back to being a natural storage unit for CO2, making the restoration of blue wildebeest one of the greatest success stories in conservation.
3. Grey wolves in Yellowstone National Park
Nowhere is the importance of wolves more evident than in Yellowstone National Park. In 1926, employees eliminated the last wolf pack in Yellowstone National Park as part of a policy to eradicate all predators.
The entire ecosystem fell out of balance. Elk populations exploded, causing overgrazing of willows and aspens. Without those trees, songbirds began to disappear, beavers could no longer build their dams as riverbanks eroded, and water temperatures rose until they were too high for cold water fish.
In 1995, just 14 wolves were rewilded. Deer and elk populations responded immediately, trees rebounded, riverbanks stabilized, and birds returned along with beavers, eagles, foxes, and badgers. Scientists celebrate it as one of the greatest rewilding efforts ever. As of December 2021, at least 95 wolves are in the park.
4. Water buffalo in Ukraine
In many communities across Eastern Europe, water buffalo were a familiar scene. But, political and industrial upheavals throughout the 1900s wiped out the natural and domestic populations.
As their name suggests, water buffalos are adapted to wet areas and are biodiversity and abundance creators. Feeding throughout marches, their large bodies create pools and puddles, which are home to many insects, amphibians, and fish. They are also vital seed dispersers, planting more than 200 species of vegetation via their hair or droppings.
In mid-May 2021, officials released seventeen water buffalo onto the 3,500-hectare Ermakov Island on the Danube. As one was pregnant, the number quickly rose to 18 in total. Because of the species, the entire Danube Delta is now thriving with life.
5. Plains bison in the American Prairie
Historically, researchers estimate that 25-60 million plains bison roamed the American Prairie. However, in the 19th century, settlers and hunters nearly drove them to extinction. The last wild bison population, about two dozen individuals, was only found in Yellowstone National Park.
Through their immense diet of grasses, bison keep the Great Plains ecosystem functioning, helping cultivate more vegetation, and creating habitats for other keystone species like black-tailed prairie dogs, which serve as food for predators. Droughts are also prone to this region, and the bison wallows create pools of water that many animals use as their primary drinking source.
Thus, in 2012, a coalition of biologists and conservationists set about to recover the plains bison. Via breeding programs, the population grew to almost 5,000. The reintroduction of bison was so successful that their impact on the landscape could be seen from space.
6. Muskoxen in the Arctic
While the Arctic has generally acted as a natural carbon sink for the past 10,000 years, the impact of climate change has recently seen some areas transition towards carbon source status. Herbivores, like the Arctic muskox, are an essential part of the ecosystem and have been found to impact the carbon cycle in the region significantly.
Well-adapted to life in the frozen north, muskoxen roam the tundra in search of roots, mosses, and lichens. In winter, they use their hooves to dig through snow to graze, while in summer, they supplement their diet with Arctic flowers and grasses.
In a study conducted by Swedish and Danish researchers in Greenland between 2011 and 2013, muskoxen were deliberately excluded from test areas by fencing. After several years the research team observed the removal of the muskoxen meant plants only absorbed half as much carbon during the growing season.
There are around 170,000 muskoxen currently living across the circumpolar tundra, concentrated in Greenland and Canada. With the Earth’s climate rapidly warming, their conservation is being considered in Arctic climate models.
These six stories showcase the importance of rewilding large mammals. Wildlife recovery supports global biodiversity objectives, helps mitigate climate change worldwide, and creates a better habitat for all.Explore more videos on species rewilding