A Late Permian scene features one of that period’s famed extinction survivors, Lystrosaurus. Image: © California Academy of Sciences | Illustration by Marlene Hill Donnelly.
In the first study of it’s kind, researchers have been looking at how food webs survived the Permian-Triassic extinction event, one of the “big five” extinction events that have happened in the Earth’s lifespan. They’re especially interested in studying how ecosystems dealt with such change, because many scientists believe that we are currently witnessing the sixth great extinction, the first caused by human activity.
Between climate change, pollution, habitat destruction, and global extinctions, humans are harming the environment on a scale not seen since the last great extinction event. And because we didn’t live through any of those, we can’t yet predict how the world will change.
That was the point of this study, co-authored by Peter Roopnarine and Kenneth Angielczyk, which used computer models to try and simulate how food webs changed as a byproduct of the Permian-Triassic extinction.
They found that the strongest models were those that were dominated by large animals, and that in food webs that were dominated by small reptiles and mammals; things didn’t go all that well. We tend to think of rats as able to survive just about anything, but their ancestors weren’t so adaptable.
The problem, of course, is that humans have a tendency to wipe out large animals, like rhinos, whales, or tigers. These, traditionally, have been the kind of creatures that we’ve over hunted, or have pushed out of their habitats for our own use. Meanwhile, creatures like rats have survived because they’re adaptable, but relying on them to keep their ecosystems balanced isn’t a great idea.
One thing that we have learned from this study is that we don’t know enough about our current ecosystems. We need to study the way creatures interact within food webs, in order to understand which species are most important for the stability of those food webs.
While it’s important to preserve all species in an ecosystem, when it comes down to it, we may have to choose some over others, and we may need to know which species we can afford to lose, and which we can’t.
