The keystone species: one animal holding up a system
Launch library · evergreen read
A keystone species has an influence on its ecosystem that is disproportionate to its numbers. Remove it, even though it might represent a small fraction of the total biomass in an area, and the whole system can shift shape, sometimes dramatically, in ways that ripple through species that had no obvious connection to it.
The classic mechanism is indirect: a predator keeps a grazing species in check, which in turn allows vegetation to recover, which in turn supports the smaller species that depend on that vegetation. Remove the predator and the whole chain can unravel, step by step, over a surprisingly short span of time.
Identifying a keystone species is one of the more practical tools in conservation, because it lets a limited budget focus where it will do the most good: protecting or reintroducing a single species, rather than attempting to manage every part of a system at once.