by Sherry Marr
I was fascinated when I first learned about the re-introduction of wolves into Yellowstone National Park, after an absence of seventy years, and how this impacted, in what is called a trophic cascade, everything in the ecosystem, ultimately actually changing the course of the river.
Nature is amazing!
A trophic cascade is a series of consequences, starting at the top of the food chain, that affects all the species lower down.
Yellowstone Park was created in 1872. Poachers, hunters, tourists and park rangers were free to kill wolves, who were considered a nuisance and given no protection at all. By 1926, wolves had vanished from Yellowstone.
The park began to suffer from the absence of wolves. There was an increase in grazing populations, and human efforts to cull the herds weren’t successful. Areas along riverbanks were denuded, soil erosion occurred, and small species withdrew.
Scientists argued for the re-introduction of wolves into the park, but park rangers were opposed. In 1967, wolves were classified as endangered. But it wasn’t until 1973 that U.S. Fish and Wildlife were required to do something about it. Years of studies were begun, working towards a restoration program.
Paul Nicklen, National Geographic photo
Finally, in 1995, fourteen wolves were captured in Alberta, Canada, and introduced into Yellowstone. The results were astonishing. Grazing herds moved away from the riverbank to less open locations. With less grazing, forest regeneration stabilized the slopes; there was less soil erosion. Pools started forming; rivers became narrower. The wolves had impacted the physical geography of the entire park.
This all blows my mind. They say the increase in songbirds, beaver, and small animals like gophers and ground squirrels, which fed eagles and hawks, was amazing. Landscape that had been grazed bare became lush and green once more. Willows grew and spread. The area healed and grew into a paradise.
Best news of all, to me, is that wolves were removed from the endangered species list in 2009, as their numbers had become sustainable.
This is all marvelous to contemplate, and makes me ponder how every species has its important role to play in the working of whole ecosystems. The participation of each impacts the health of the whole. Or, as my Nuu chah nulth neighbours teach: Everything Is One. What happens to one, happens to us all.
Here is a little-known fact: salmon change forests too! One doesn’t think of salmon as having a connection to the forest. But eagle, bears and wolves all eat salmon. Fish carcasses and the droppings of the animals that eat salmon are compost, adding necessary nitrogen to the trees and the forest floor. They keep forests thriving. Here on the West Coast, our salmon stocks are dying out, because of climate change, warming seas, over-fishing, and, especially, pollution and disease from the open-pen fish farms in the area. First Nations have been advising of this danger for decades, yet governments are slow to act in legislating fish farms into contained land-based locations. I fear our salmon will go the way of the cod stocks of the eastern seaboard before long.
The Nuu chah nulth people have lived off salmon for ten thousand years. It only took greedy settlers a couple of hundred years to plunder everything into near-extinction. I can’t imagine, as outraged as I am by environmental degradation, what it must be like for the original people of this land – its caretakers and guardians – to watch everything being destroyed: salmon dying out, forests being clearcut, everything being paved over in an accelerating rush to grab it all before it all is gone. I am astounded by how patient the First People are, and how willing, still, to talk to us and try to help us learn.
It saddens me to reflect on the outrageously heavy and disproportionate impact our human species has, the harsh toll it is taking on the non-human realm – who have as important and necessary a role to play as we do in an interdependent ecosystem, and as much right to life.
“Mother Nature provides for our need,” a local Chief often repeats, “but not our greed.”
Let’s think about this for our challenge: Share any example you wish of a human or non-human being, and the impact it has on its surrounding ecosystem. Share your wonder, your despair, your hope, your respect: whatever this challenge brings up for you. I look forward to being amazed.