We show that the extinction of one species can often be compensated by the concurrent removal or population suppression of other specific species, a counterintuitive effect not previously tested in complex food webs. These compensatory perturbations frequently involve long-range interactions that are not evident from local predator–prey relationships. In numerous cases, even the early removal of a species that would eventually go extinct is found to significantly reduce the number of cascading extinctions. These compensatory perturbations only exploit resources available in the system, and illustrate the potential of human intervention combined with predictive modelling for ecosystem management.
From the abstract for “Rescuing Ecosystems From Extinction Cascades Through Compensatory Perturbations,” a paper by Northwestern University ecologists Sagar Sahasrabudhe & Adilson E. Motter published today in Nature Communications. Sahasrabudhe and Motter show that ecosystems have multiple balance points, and that ecologists might learn to forestall extinction of a selected species by the removal or “suppression” of another species.
Reporting on the study at Nature News, Emma Marris points to the example of the management of fox populations on California’s Channel Islands, where introduced feral pigs brought eagles that opportunistically fed themselves not only on free-range pork, but fox as well. Worried that the eagles would simply drive the foxes to extinction, planners trapped and relocated the eagles before eradicating the feral pigs—which as a species distinctly lacking in charisma likely faced a “relocation” more metabolic than geographical.
Is that kind of natural resources management “natural”? The very terms of our cherished notions of the natural are moot. As habitats inexorably shrink into islands of forest and steppe before the advance of humankind, as climatic bands march north and sea levels shift, their appointed human managers face political, economic, and popular pressure to husband nature with the efficiency of sysadmins. Under the pressure of burgeoning technology, two curves of complexity approach an intersection: computer networks growing in speed and power approach the complexity of biological phenomena, while ecosystems, ever more segmented and parsed into pieces, seem to drift towards the manageability of computer networks. Over at Quiet Babylon, Tim Maly ponders scries the transformed terms by which we come to nature in a smashing post on Cyborg Ethics of Eating. Maly asks whether we’re reaching the point at which we shoulder the burden of our technological apotheosis, and replace eating altogether with some kind of machinic transubstantion of the meat wheel:
As we come to grips with the fact that our civilization is terraforming the planet whether we meant to or not, this seems like an increasingly reasonable move. We are already capable of wrecking the ecosystem and we are hoping to become capable of fixing it. How wonderful might it have been to have had the climate change debate before we started changing the climate.
Grasping nature’s trophic handles, we’re becoming a YouTube, vernacular-video version of Kafka’s Hunger Artist. In that story Kafka imagines a maestro of starvation, wasting away before audiences who vicariously partake of his self-abnegation. Perhaps through the ever-more precise management of resources we can painlessly realize the hunger artist’s virtuosic famine. Jeff McMahan, a philosophy professor at Rutgers, goes further, arguing for the forced extinction not only of key predator species in at-risk ecosystems, but all carnivores in the biosphere, on the grounds that suffering caused by predation is a moral outrage.
It would be good to prevent the vast suffering and countless violent deaths caused by predation. There is therefore one reason to think that it would be instrumentally good if predatory animal species were to become extinct and be replaced by new herbivorous species, provided that this could occur without ecological upheaval involving more harm than would be prevented by the end of predation.
It’s an ancient desire, evoked most forcibly in Isaiah 11:
6 The wolf will live with the lamb,
the leopard will lie down with the goat,
the calf and the lion and the yearling[a] together;
and a little child will lead them.
7 The cow will feed with the bear,
their young will lie down together,
and the lion will eat straw like the ox.
8 The infant will play near the cobra’s den,
the young child will put its hand into the viper’s nest.
Isaiah relied on the grace of knowledge of the Lord to fulfill this vision; now, we’re hoping there’s an app for it.