Feb 27, 2012


No Wolves, No Water Here’s the piece we still don’t get: when we exterminated wolves from Yellowstone in the early 1900s, killing every last one, we de-watered the land. That’s right -- no wolves eventually meant fewer streams, creeks, marshes, and springs across western landscapes like Yellowstone where wolves had once thrived. The chain of effects went roughly like this: no wolves meant that many more elk crowded onto inviting river and stream banks where the grass is green and the livin’ easy. A growing population of fat elk, in no danger of being turned into prey, gnawed down willow and aspen seedlings before they could mature. Willows are both food and building material for beavers. As the willows declined, so did beaver populations. When beavers build dams and ponds, they create wetland habitats for countless bugs, amphibians, fish, birds, and plants, as well as slowing the flow of water and distributing it over broad areas. The consequences of their decline rippled across the land. Meanwhile, as the land dried up, Yellowstone’s overgrazed riverbanks eroded. Life-giving river water receded, leaving those banks barren. Spawning beds for fish were silted over. Amphibians lost precious shade where they could have sheltered and hidden. Yellowstone’s web of life was fraying and becoming threadbare.