Research has shown restoring so-called"keystone" species -- those with an outsized impact on their environment -- is vital for the health of ecosystems, and can come with unexpected benefits for humans.Few species evoke the American wild as much as wolves.
Then, in the mid-1990s, the government took wolves from Canada and reintroduced them to Yellowstone National Park.The new arrivals kept elk numbers down, preventing them from over-browsing vegetation that provides material for birds to build nests and beavers to build dams -- a phenomenon known as a trophic cascade.
It's thought there are now more than 6,000 gray wolves in the contiguous United States. The main threat is legalized hunting in some states.The story of the American buffalo -- also known as bison -- is inextricably linked to the dark history of the early United States. The buffalo, who were introduced there in 2014 and now number around a hundred, favor eating grass over flowering plants and legumes, which in turn allows a variety of birds, insects and amphibians to flourish.
Some 20,000 buffalo are now thought to roam in"conservation herds," though none are truly free roaming, added Considine.As the dominant predator of marine nearshore environments, sea otters play a hugely important role in their ecosystem.