The 1995 reintroduction of wolves to Yellowstone National Park is a well-known conservation story, where the native predators were observed to return balance to the ecosystem.In opposite fashion, non-native lake trout that have become established in Yellowstone Lake are now outcompeting native cutthroat trout and seriously altering the overall ecosystem, both in and beyond the lake, and largely unseen.“We see animals moving through valleys [but] do not see connections breaking between lakes, streams, and the surrounding landscape,” a new op-ed argues.This article is a commentary. The views expressed are those of the author, not necessarily of Mongabay.
Yellowstone National Park is often told as a story of recovery. Wolves returned and then elk changed their behavior. Willows and aspens then rebounded and rivers, it is said, changed course. The reintroduction of wolves in 1995 is one of the most familiar ecological narratives in the world.
But the Yellowstone ecosystem was not waiting in a stable state for wolves to return, it had already been reorganizing for centuries. Beavers declined following widespread trapping, altering vegetation and hydrology. Grizzly bears were heavily persecuted across the region, reducing another major connector between aquatic and terrestrial systems. Bison were reduced to near extinction in the late 19th century and later rebuilt under protection. Large predators were removed in the early 20th century, and elk populations expanded in their absence. Each of these changes altered how nutrients moved and how water, plants, and animals interacted.
