Transcription
So here's a shocking fact: In the Pacific Northwest, the trees need salmon. What? The trees need salmon! Do you want me to unpack this a little bit as to how I got to that "aha!"?
Something that's generally true about nature, including our bodies, is that there are all sorts of substances, some in very small amounts, some in sort of medium amounts, and some in large amounts. Those levels, those amounts, are kept in check by various body systems, by all sorts of regulatory systems. Some of that is feedback regulation.
That's important because sometimes if we have too much of one thing, that's a disease; too little of something, that's also a disease. For scientists to figure out the rules of regulation in the body, to know what the right level of insulin is or what the right level of red blood cells is, has been really important for managing health and various situations.
What's true for the body is also true in broader nature. It turns out there are rules in nature that govern the relative abundance of plants and animals. When we understand those rules, we know better how to manage those places for sustainability, for their health and our health.
While society's been humming along and enjoying all these advances in agriculture and medicine, in the last 50 or 60 years, ecologists have learned a lot about how nature works. I've codified these into a set of rules called the 'Serengeti Rules.' I call them the Serengeti Rules because you can see them in operation in the magnificent Serengeti. You can see them in operation in all sorts of other places like Lake Erie, but I don't think 'Lake Erie Rules' would've sold as many books.
A couple of those rules that are really important are that some animals are more important than others, meaning they have an outsized impact on the communities in which they live. There's sort of this poetry about nature, you know, every creature has its place and its purpose, and everything is equally important. That's not true.
The functioning of these ecosystems is sometimes much more dependent upon certain individual species or small groups of species than others. That's really important knowledge because if we lose those species, those communities can collapse. If those communities are somehow compromised, reintroduction or boosting those species can have great knock-on effects on the overall health of the ecosystem.
For example, in Yellowstone National Park in the United States, it's a pretty famous story of the reintroduction of wolves, which had been exterminated from the Lower 48. The last wolf was killed in Yellowstone in about 1924. So there had been no wolves for 70 years in Yellowstone. You might say, "So what?" We can get along without these large predators.
Well, that's been shattered by ecological discoveries. These large predators play a really important role. In the case of Yellowstone, essentially, trees need wolves. So think about that for a second. Trees need wolves. How do you draw that connection in your head?
It's by wolves controlling the browsing and grazing of deer and elk. That was absent for 70 years, stunting plant and tree life in Yellowstone. Wolves were reintroduced in 1995, and within a decade, you could see changes in the landscape of Yellowstone. Those changes led to increased abundance of other sorts of creatures.
Similarly, we know that some species have really strong indirect effects on others. For example, in the Pacific Northwest, the trees need salmon. Rivers don't have a lot of nutrients. A lot of the nutrients in those rivers come in from the ocean in the form of salmon bodies.
When those salmon are taken by all sorts of carnivores, and when those carcasses are left on the stream banks, the nutrients from those carcasses fertilize the trees. We can actually trace those nutrients from the ocean into the trees in the Pacific Northwest. Who would've thought of such things?
As we've learned about all sorts of hidden connections in ecosystems, we're realizing, first of all, why some of our actions were so damaging. But the flip side of that coin is why a little bit of action now can be so rewarding, so positive, and that these systems, these webs of life, can be restitched just by the introduction of certain key creatures.
This is really important because we are nature's managers now, whether you like it or not; we've taken it over. We're trying to manage nature for the long run so that we have the things that we need, and hopefully nature can persist.
So we need to keep exploring these interactions, whether they're interactions within the body or interactions out there in nature, to manage our future. You see the payoffs in medicine; every discovery, every new medicine, the way we manage so many diseases, that's entirely the fruit of the last 50 years of understanding these basic rules.
We need that same sort of mindset to be taken outdoors into nature so that we can manage the planet better. If we managed our bodies the way we managed the planet, there would be a revolution.
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