Faye Moyes was staring at a spreadsheet of 60,000 shimmering data points—each one a pulse in the life of a wild population—when the pattern snapped into focus: species fading from their local homes were far more likely to be on the brink of vanishing entirely. Her team’s groundbreaking study, led from the University of St Andrews, has uncovered a powerful signal in the noise of global biodiversity loss—local declines are not just isolated events, but early warnings of extinction risk. Drawing on the vast BioTIME database, one of the most comprehensive records of biodiversity change ever assembled, the researchers analyzed over two decades of population trends across 2,362 species, from coral reef fish in the tropics to songbirds in temperate forests. The goal? To see whether the quiet disappearances happening in backyards, reefs, and reserves could reveal something larger—the global fate of a species.
This matters because extinction risk today is largely assessed through dedicated, species-by-species evaluations by the International Union for Conservation of Nature (IUCN) Red List. But with over a million species at risk and limited resources, many go unassessed. The St Andrews team asked a different question: can we use routine, local monitoring—often overlooked—to flag danger before it’s too late? Their answer is a resounding yes. When populations consistently decline in prevalence over time, the species they belong to are significantly more likely to be classified as threatened. Remarkably, fewer than 10% of populations showed clear increasing or decreasing trends, but those that did told a powerful story. Even more telling, some species not currently listed as at risk showed widespread local declines—silent alarms that could reshape conservation priorities.
The study, published in Nature Communications, is the first to systematically link assemblage-level monitoring data—groups of species coexisting in the same place and time—to global extinction categories. Joint lead Laura Antão of the University of Turku emphasized the breakthrough: “We have assessed for the first time whether there is a consistent signal between population temporal trends and a species’ extinction risk status using assemblage monitoring data.” The findings reveal that not all threatened species are declining everywhere—some populations remain stable, offering hope and a focus for targeted action. Conversely, some seemingly secure species are quietly slipping away.
For conservationists, this is transformative. Professor Anne Magurran, a senior author, sees these trends as early-warning systems—tools to direct monitoring and protection where they’re most needed. And with the BioTIME database and IUCN assessments only partially overlapping, the study proves that combining existing data can dramatically expand our understanding without waiting decades for new fieldwork. As environmental change accelerates, the ability to detect risk earlier, faster, and more broadly may be our best hope for staying ahead of the extinction curve.