California’s legendary mountain man, John Muir, once wrote “When we try to pick out anything by itself, we find it hitched to everything else in the Universe.” Muir’s observation about the connectedness of things in nature may have been intended more as a metaphor than as a scientific fact, but in the hundred years since he wrote that sentence, scientists and researchers studying natural ecosystems are finding Muir’s metaphor to be the literal truth.
Wolves Change The River
Take the story of the reintroduction of wolves to Yellowstone National Park in 1995 after an absence of seventy years. Within just a few years of their reintroduction, they began to transform the ecosystem of the Yellowstone valley. As the wolf packs hunted elk and bison, whose populations had previously boomed from lack of predators, causing overgrazed grasslands and forest canopies, willows began to grow again along the river banks. Beavers returned, their dams creating habitat for fish and other river creatures. As vegetation increased and expanded, the barren, eroded river banks were stabilized, their channels running deeper, faster, and cleaner. The wolves’ return had literally re-made the river.
Salmon Grow Forests
The epic journey of Pacific salmon— from their birth in coastal freshwater streams and rivers, migration to the ocean to mature, and return to spawn in the headwaters where they began— is a defining cycle in the Pacific coast ecology. The protection of salmon fisheries, salmon spawning streams, and river runs has driven ecosystem restoration along the Pacific coast from the San Francisco Bay to Alaska. But as we try to save spawning runs and the forests of the headwaters for salmon populations, it may be that the salmon themselves are saving the trees. Studies of trees along salmon spawning runs in Alaska and the Pacific Northwest show that as much as eighty percent of individual tree nitrogen content is derived from salmon nutrients. The salmon that have died after spawning or been eaten by bears, birds, or other animals, are transformed into nitrogen in the forest soils that feed the trees. Even in small coastal watersheds, trees hundreds of feet inland from salmon spawning runs show the nitrogen “signature” of salmon in their tree rings. The fish are growing the forest.
Watersheds Connect Us
As we learn more about the complex interactions of our ecosystems, it is harder to ignore the interconnectedness of things. As we find we really are “hitched to everything else…,” it is easier to see that everything we do has an effect on the life— and landscape— around us. One way to make the connection between ourselves, our communities, and the environment is through the lens of our watersheds. A watershed does not have a visible boundary, but rather it is a web of connections between living things and everything that sustains them. We are a part of that web, along with the wolves and the salmon, the redwood and kelp forests, the creeks and the marshes, and the bay and ocean. And like the Yellowstone wolves who restored the river, and the Pacific salmon that grew the forest, we can make positive changes in our own watershed. You can help create change by joining The Watershed Project during our upcoming Earth Day events! We only have one true watershed, but we’re all connected and are responsible for its health.