Some years ago I contributed, like so many others, to spreading a little nature documentary on social media. The film was called How Wolves Changes Rivers, and portrays the return of the wolves to Yellowstone national park in USA. Many people probably thought the story of the positive and pervasive effects of the wolves had in the park was too good to be true. Such a reserve is healthy, but in actual fact the idea of reintroducing one key species into an ecosystem was supported by rigorous science.
The documentary film The Serengeti Rules provides a fascinating introduction to the background of it all. We encounter five people who in the 1960s developed a passion for investigating and understanding life – in forests, rivers and oceans. They didn’t know each other, and apparently they were researching entirely separate topics.
The main voice of the movie belongs to Robert Paine, who relates from his death-bed how he ended up uniting these dissimilar scientists in a common project. His scientific gaze had a farther reach than most, as his fundamental ambition was to uncover the self-regulating mechanisms of nature. Science had long departed from the premise that the energy of the sun provides nutrition for the plant eaters who, in turn, are devoured by the carnivorous animals in a process that goes from bottom to top. But what if the relationships in nature were more complex? What if life trickled down just as much as it grew upwards?
Some species are more important than others
Robert Paine launched a simple experiment to examine such questions. In a stretch of the intertidal zone, where 15 different species lived symbiotically together, he removed the starfish. After a short time the ecosystem was completely taken over by mussels. The fact that the carnivore (in this case, the starfish) disappeared, made it possible for another species to dominate to such an extent that it suppressed all others, thereby creating a monoculture. If Paine removed any of the other species, nothing happened. The starfish stood out. It was a keystone species in the ecosystem, decisive for its biodiversity.
When the otter disappeared in the waters outside northeast America, the consequence was a blossoming of sea urchins.
As a consequence of this new-won insight we also learned more about how humans disrupts the balance of nature. When the otter disappeared in the waters outside north-east America, the consequence was a blossoming of sea urchins. Since they are plant-eaters, the rich marine life was rapidly changed into a desert. What caused the disappearance of the otter? The answer was to be found in the sperm whales who ate them, a change of eating habits that was caused by human intervention. This shows that industrial harvesting of certain species can create disturbances which then spread through the ecosystem. The long term effect was that human activity caused the natural diversity to deteriorate to the detriment of the ocean’s capacities to sustain and regenerate life.
Human interference and the way onwards
Sadly, such stories abound, caused by human population growth, a dismantling of wild nature and changes in the landscape along with different kinds of pollution disrupting essential ecosystems that have evolved through millennia. Often, isolated encroachments trigger domino effects spreading unpredictably through several connections at the same time. A major challenge is that humans tend to make any change into a new norm, thereby losing our understanding of the ways our surrounding nature is damaged by human activity.
The degradation of ecosystems, as well as mass extinction and loss of biodiversity, is a reality we need to take much more seriously. A critical question that arises is whether nature can be restored at all. Here the Yellowstone wolves become important, since they demonstrate how the re-introduction of a lost species can revitalize the life of nature. Hence, in different contexts we would need to know which species are key to the mutual interactions of an ecosystem. In one place it was the wolf, in another, the starfish or the otter – and in the Serengeti national park, it turned out to be the gnu.
We would need to know which species are key to the mutual interactions of an ecosystem.
The relationship between nature and natural science creates an essential nexus here, where sociological concerns tie in. What does it take for our society to take care of our ecological knowledge in a responsible way? Is the solution to be found in absolute distinctions between what we can meddle with and what needs full protection, or do we have to resign to the notion that in the Anthropocene we protect, preserve and administer a world that we have always been changing?