Once hunted as nuisances, beavers “are being welcomed into the landscape as a defense against the withering effects of a warmer and drier climate” in the U.S. West, says the New York Times. The nocturnal, semi-aquatic rodent builds dams that prevent water from draining away. “They raise the water table alongside a stream, aiding the growth of trees and plants that stabilize the banks and prevent erosion. They improve fish and wildlife habitat and promote new, rich soil,” says the Times. There are disadvantages – a study in Arizona found new beaver ponds were ideal for invasive fish that displace native species.