translated from Spanish: The band of scientists who discovered the rules that govern life on the planet and turned our worldview to the head

The story referred to by biologist Sean B. Carroll is indeed one of landscapes recovering, forests reappearing, returning species and lives flourishing.
All thanks to the pioneering work of five scientists “who you may not have heard of, but who have something important to tell you.”
In the space of six decades, each added knowledge from their place in the world, testing a hypothesis until it became a revealing theory.
“They saw things that no one had seen before, they thought things that no one had thought until then and what they discovered changes the way one sees nature,” Carroll stresses, in conversation with BBC Mundo.
And he doesn’t exaggerate.
But they also demonstrated that while human intervention may be, and has been, harmful to the planet, it can also be beneficial, “something that is very much needed at the moment.”
What we knew
All those scientists came out with a worldview that might be familiar to you.
It is that the way the world works is that plants receive sunlight and turn it into food; some animals eat those plants and then some predators eat some of those plant eaters.
But in the 1960s one of them, American environmentalist Bob Paine, wondered if the predators were really nothing more than that, if their role in nature really came down to eating meat in that food chain.
The problem was how to investigate it… “You can’t take all lions out of an environment to see what happens,” Carroll says in his book “The Rules of Serengeti: The Search to Find Out How Life Works and Why It Matters.”
I needed a place where an entire system was contained and out of manageable size.
He found it in the tidal pools of a bay in the northwest Us called Makah, where he lived everything he needed: about 15 species of organisms, carnivorous gasteropods feeding on barges, sea urchins feeding on algae…
The tidal pools were full of life… and starfish… and, most importantly, a great predator: starfish.
“You see them and think, ‘How pretty!’ but they’re ferocious. They’re mass consumers. They eat barbes, they are fascinated by mussels… they are the lions of the tidal pools,” Paine says in The Passion Pictures Films documentary “The Rules of Serengeti,” based on Carroll’s book.
With and without stars
The experiment could begin.
Paine pulled the stars out of one of the pools but not from another and for months watched as it passed.
He soon began to notice the changes in the pool without stars: the mussels began to multiply, while other species were disappearing.
The pools were a natural laboratory that allowed Bob Paine to make the equivalent of taking the lions out of Africa to see what was going onAfter a few years, of the 15 species that had originally only left the mussels.
Crucially, in other pools, Paine withdrew other species and in none of those cases the same thing happened.
Clearly, the diversity in those tidal pools depended on the stars.
The predator was the bastion of the system.
Their experiments showed that in mature ecosystems some animals are more important than others.
He called them “key species”, in the sense of the dovelas or key stones in the Roman arches, because if you remove them, the entire arch collapses.
The exception or the rule?
Paine had laid the foundations, but it was necessary to know whether what he had discovered was a rule of life or a peculiarity.
Luckily, science is usually a teameffort, so you don’t work at the same time or in the same place.
Science is usually done like a puzzle: Paine had found the first pieceIn southwest Alaska there is a volcanic island called Amchitka, where when you arrive you get a sign that says: “It’s not the end of the world… but from here you can see it.”
The end of the world was not exactly what marine ecologist Jim Estes had dedicated himself to seeing in the remote place.
His interest was underwater, where he had found a forest of algae that – like those of earth – provided a habitat for many species, including a large number of otters.
One day Bob Paine came to the place and suggested that instead of seeing the forest as the support of otters, he would think of otters as predators…
“That was the beginning of the rest of my life,” Estes says in the documentary.
This sympathetic creature turned out to be the key speciesTo see what effect these carnivorous mammals had on the system, visited a nearby island called Shemya where there were none, and when he submerged his head underwater, instead of a forest full of life , found a desert populated only by hedgehogs.
Estes knew that otters ate many hedgehogs and that hedgehogs ate many algae. Without the otters, the hedgehogs had multiplied uncontrollably and all the algae had been eaten; without the algae, all the other species had disappeared.
Without the predators to protect it, the underwater forest could not exist.
On the mainland… Venezuela
Something similar saw in the 1970s environmentalist Mary Power – who had been Paine’s student and had read Estes’s reports – in some streams in Oklahoma, USA.
He noted that some of them had formed a series of sterile pools interspersed with pools of a vibrant emerald green color.
After researching and experimenting, he found that the difference was due to the presence or lack of the key species, which in this system was the Micropterus salmoides, commonly known as atruchada or American perch, huro and black bass.
Mary Power found that the phenomenon also occurred in fresh waterThe result of Power’s work in streams, Paine in the tidal pools and Estes in the ocean proved that the hypothesis of the key species was true in a wide range of aquatic environments.
A ground experiment was missing and Lake Guri in Venezuela provided it.
The huge lake had been created with the construction on the Caroní River of the Guri Dam, which had produced many islands, most without predators.
It was ecologist and conservation ecologist John Terborgh who explored them and recalls that when he went to see them, “it looked as if they had been wiped out by a hurricane.”
What was a beautiful forest, a few years later it diedIn some islands, the leaf-cutting ants had reproduced uncontrollably given the absence of warrior ants, so they had defoliated the trees over and over again until they were killed.
“The phenomenon was repeated, in different ways and with different key species, but the result was always the same: what had started as a beautiful green forest, in 20 or 25 years was just rubble,” says Terborgh.
The Mystery of Otters
What these scientists were shaping was a whole new way of looking at the world. It brought down preconceptions and revealed completely unexpected hidden connections between creatures and nature.
But there was still a long way to go to understand how deep and long these connections were.
When Jim Estes returned to Amchitka Island, he was disturbed by what he saw (or rather, what he did not see)It was Jim Estes, when he returned to Amchitka Island in the early 1990s, who discovered it.
“It was crazy: when I left there were 8,000 otters and five years later, there was almost none left!”
Not only there but throughout the archipelago of the Aleutian Islands, of which Amchitka is part.
“It was the disappearance of several hundred thousand otters, a decline of 95-99%, missing without any bodies being seen in the vicinity.”
Soon, Estes noticed another astonishing change: “In the ’70s and 80s I ran into an orca every three or four years. In the ’90s, I started seeing them three or four times a day… and they were eating not only the otters, but other missing animals.”
What had happened?
Although at the time it was not obvious, it had been the work of the key controller: the human being.
We have often removed the key predator from natural ecosystems, but in this case, it was not about the elimination of a predator, but of its food.
The cause of such a dramatic event was industrial whaling that in the North Pacific Ocean began after World War II and continued until the early 1960s.
By then, the large whales in the North Pacific had been decimated.
Beautiful… and hungrySacarte the system shocked as they were large and highly nutritious for orcas, who were forced to expand their diet.
The first thing they ate was seals, until they were done with them. Then sea lions. When they ran out, it was the turn of the otters.
The impact affected virtually everything. From salmon to seabirds and bald eagles. The whole system collapsed.
Vast scales
For Estes, recognizing that nature is connected on such vast scales of space and time so importantly was a revolution in his scientific thinking.
Armed with this whole new vision, it was possible to begin to notice things that were not seen despite being right under our noses.
“If I tell you, no more, ‘trees need wolves,’ you may be amazed, but such revelations arise not from looking at nature as if it were a pretty picture but are the result of that understanding of how nature works,” Carroll tells BBC Mundo.
To understand it better, look at this image below… notice something weird?
If you didn’t notice anything peculiar it’s because we’ve gotten used to seeing as normal degraded landscapes.
The one in that photo is typical of a forest in which, in the absence of a predator – the wolf – the deer are hthey multiplied uncontrollably into a plague and have eaten everything that should be alive between where the lowest branches you see and the ground end.
This is a forest in demise: there are no new trees because they have eaten them, so when they die, there will be no more forest.
It is not a one-off example; in fact, “much of the world we see today is degraded,” Carroll ruling and, once again, does not exaggerate.
But all this is sounding very pessimistic and we had promised you a story of hope.
What happens is that we are missing a key piece of this puzzle, which scientist Tony Sinclair discovered working in one of the most iconic places on the planet: the Serengeti National Park in Tanzania.
More and more and more than anything
When Sinclair began working at Serengeti, though he did not realize at the time, even the world’s most famous national park was heavily degraded.
The wildebeest had been victims of bovine plague 120 years ago, an epidemic of bovine plague, very similar to measles, decimated the local animals, particularly wildebeest, whose population remained low for 70 years, until in the 1960s, veterinarians veterinarians managed to eradicate the disease in most of Africa.
By the time Sinclair arrived, the improvement was beginning to obvious.
“When I arrived, there were about 250,000 wildebeest; eight years later, it was 1.4 million,” Sinclair says.
“It was a world record, the largest ungulates population in the world.”
Sinclair excitedly attended a meeting in 1982 to tell the world what was happening.
“When I said the figure of 1.4 million, there was a deadly silence. I didn’t expect that reaction at all.”
Their counterparts thought it irresponsible to allow them to multiply in this way and claimed that they had to be sacrificed because they were going to destroy habitats and cause a system collapse.
“But, I thought, why should humans interfere? These systems have been around for millions of years without human interfering being required to persist.”
Tony Sinclair refused to sacrifice wildebeest and preferred to rely on natureAlthough aware that he was putting at risk one of the iconic locations on Earth, Sinclair’s team decided to stand firm and convinced the park authorities not to give in sacrifice.
The censuses of the following four years yielded the same result: 1.4 million. The system had leveled itself and there was no damage to the environment.
“Quite the opposite: to our surprise, we discovered that the system was repairing itself. Suddenly, everything started to reconnect,” Sinclair says.
“The wildebeest produced manure, which fertilized the pastures, which became highly nutritious. And, by eating them, there was less fuel and therefore less fires.
“That allowed tree populations that probably hadn’t grown since the 19th century to increase. These trees provided more food for elephants, giraffes and many, many bird species.
“And that attracted a lot more predators because there was more food for them, too.”
“I realized that wildebeest was a key species and that, contrary to what Bob Paine had assumed – that the key species was always a predator – it could actually be a herbivore.”
The return of the wildebeest to Serengeti changed everything for the betterBesides that, and perhaps more importantly, what Tony Sinclair’s studies showed was that even though that key species had been lacking for 70 years, the resilience of the ecosystem had not been depleted .
And when the key species reappeared, Serengeti changed deeply: more trees, more giraffes, more songbirds, more butterflies, more beetles, more and more and more and more of all.
It was a large-scale test that degradation is not a condemnation: it is reversible.
You have to put the star in its place
Bob Paine had been the first to glimpse it: if you eliminate the starfish, biodiversity collapses.
60 years after his experiment, prominent environmentalists compared experiences and it became clear that this is the way nature works. Everywhere.
They had revealed the rules of life on the planet.
“If you want to fix something, you need to know what’s damaged,” Paine said.
And because he and that handful of scientists, it’s possible to find out.
Look at the difference that salmon reintroduce stomping on this riverNow, seeing those degraded landscapes instead of staying in negative, pessimistic, fateful comments, we can ask ourselves: are we doomed? Is the destination sealed for these places and species?
And, in many cases, the answer is: “No.”
“It’s not that you’re going to find key species everywhere, but they’re prevalent!” says Carroll.
It’s a matter of finding the star equivalent for each ecosystem.
A well-known example is yellowstone National Park in the northwestern Us, where about 20 years ago, the wolf population was increased by human intervention to control the number of moose, which was seriously affecting the vegetation of the Park.
With the return of the wolves after 70 years of absence, the willows recovered, the poplars prospered, the beavers returned and the bears expanded.
And in Argentina, something amazing: in the highlands to which the cougars have been able to return, the grass grows and creates habitat for all kinds of creatures.
Wolves, so feared in the past, are now welcome in YellowstoneAnd the body of knowledge, the number of examples, is growing.
In the Midwest, there are people adding key fish to the lakes, which turn from green and cloudy to crystal clear.
In rice paddies, spiders are the key species. So if you want to eat rice, protect the spiders.
In Scotland, meanwhile, they demonstrate how their beautiful meadows should not be… Meadows.
This fenced-in enclosure shows the impact of grazing animals and what the Scottish landscape would look like without them.
And so, in many parts of the world there are similar projects that are recovering places and species.
One of the stories that has excited Carroll the most is that of gorongosa National Park in Mozambique which, as is often the most inspiring, begins with a great loss: that of its wildlife due to one of the longest, most brutal and destructive of the last decades (1977-1992).
But peace eventually brought an interest in recovering what several called Gorongosa’s “lost paradise.”
Today, as a magazine article beautifully said National Geographic, “you can see nature giving a sigh of relief.”
During the war that followed Portugal’s independence, Gorongosa was one of the main battlefields and was destroyed. Today, paradise is in the process of recovery”The project takes just over 15 years and one is terrified that things can recover at that speed,” he exclaims, in conversation with BBC Mundo, Carroll.
“You see that if you give it a chance, nature is very resilient,” he says.
“It’s not that it’s unrealistic… I’m a scientist: I believe in empirical data!”
Once you have them, make an effort to find and spread lights at the end of the tunnel.
“A lot of human history is about overcoming challenges. For that you have to use energy and vision; pessimism is a self-fulfilling prophecy, and many of us are concerned that people will give up.
“It’s not the time to give up, it’s time to redouble our efforts and ask ‘what can be done’ over and over again.
“You have to focus on the work, not the despair.”

Original source in Spanish

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