Wildfires, floods, pollution, and overfishing are among the many disruptions that can change the balance of ecosystems, sometimes endangering the future of entire species. But evaluating these ecosystems to determine which species are most at risk, in order to focus preservation actions and policies where they are most needed, is a challenging task.
Most such efforts assume that ecosystems are essentially in a state of equilibrium, and that external perturbations cause a temporary shift before things eventually return to that equilibrium state. But that assumption fails to account for the reality that ecosystems are often in flux, with the relative abundances of their different components shifting on timetables of their own. Now, a team of researchers at MIT and elsewhere have come up with a better, predictive way of evaluating these systems in order to rank the relative vulnerabilities of different species, and to detect species that are under threat but could otherwise go unnoticed.
Contrary to conventional ways of making such rankings today, they found, the species with the lowest population numbers or the steepest decline in numbers — criteria typically used today — are sometimes not the ones most at risk.
The findings are reported today in the journal Ecology Letters, in a paper by MIT associate professor of civil and environmental engineering Serguei Saavedra, recent doctoral student Lucas Medeiros PhD ’22, and three others.