This morning I watched 2 brief videos that I thought nicely complemented each other. The first is a fascinating 4 minute video about how reintroducing wolves to Yellowstone has wrought huge change to flora, fauna and even the physical world:
The term “trophic cascade” refers to the top-down alteration of an ecosystem caused when predators change the habits and numbers of their prey, thus reducing predation on the lower trophic level (or intensity of grazing if the intermediate trophic level is an herbivore).
When wolves were reintroduced to Yellowstone National Park after a 70 year absence, the trophic cascade was profound, ultimately affecting the very course of rivers.
The wolves affected where deer hung out, numbers of other birds and animals, how they affected the trees and other plants and how that affected other forms of wildlife like beaver, otters and muskrats which in turn changed even river flows.
In short, where we make even small changes to how the natural world is working we spark a chain of events with huge consequences.
A short while later I found myself viewing another 4 minute video, that shows where such chains of unintended consequences could end up. The second video, a showcase of Mars, comes from the European Space Agency:
From the highest volcano to the deepest canyon, from impact craters to ancient river beds and lava flows, this showcase of images from ESA’s Mars Express takes you on an unforgettable journey across the Red Planet.
A stunning sequence of what would be mountains, canyons, rivers, lakes and lush plains, if only Mars weren’t a sphere of dry, arid dust, highlights one potential fate of our own Earth.
The images of Mars are sweeping, gorgeous, impressive. We could easily imagine water in rivers, lakes and oceans, but there is none. It’s a dry, dead planet.
We are so privileged to live on a lush, living world, where every living thing has its role to play.