Conservation magazine’s Journal Watch Online returns from a long hiatus to report on an interesting new paper on the problems of detecting regime shifts by resilience researchers Oonsie Biggs, Steve Carpenter, and W.A. “Buz” Brock (2009. Turning back from the brink: Detecting an impending regime shift in time to avert it. PNAS DOI 10.1073/pnas.0811729106). They write:
Like the stock market, ecosystems can dramatically collapse. But how much advance notice is needed to prevent a natural system meltdown? A paper in Proceedings of the National Academy of Sciences says the answer might be several decades, which means today’s warning systems don’t detect changes nearly far enough in advance.
Using Northern Wisconsin’s sport fishery as a model, University of Wisconsin researchers determined when an ecosystem reaches the brink of an unstoppable shift, then estimated when recovery efforts must start in order to avert collapse. They found that some rapid actions only need short timetables; angling cuts can prevent permanent damage to fisheries even if they’ve been declining for ten years. But other changes, like restoring habitat after too much shoreline development, must start as many as 45 years before ecological health indicators start wobbling.
The problem is, most indicators in today’s early-warning systems can’t detect serious shifts that far out. Even if they could, it might still take policymakers years to enact recovery schemes. Which leads the authors to plea for indicators that work on a longer horizon, and for policy makers to move swiftly once scientists buy them some time.