Arctic wading birds lay eggs when their food supply—flies and other bugs—is most abundant. And new research shows that insects are now emerging in northeastern Greenland as much as a month earlier than a decade ago.
"Since the arthropods have advanced [their springtime emergence] more than the shorebirds, one could expect the advancement to be an advantage to the birds' reproductive success," says biologist Toke Høye of the University of Aarhus in Denmark. "There is more likely to be a better match between insect appearance and egg-laying in shorebirds now than earlier."
Høye and his colleagues trapped insects, weighed chicks and counted buds from plots in Zackenberg, Greenland, during the spring and summer months from 1996 to 2005. Over that relatively short span plants budded as much as 20 days earlier, dark-winged fungus gnats led all insects by appearing nearly a month early, and small wading birds known as ruddy turnstones laid eggs after migrating from Africa and Europe a full 10 days earlier on average.
Among all plants and animals measured, springtime activity had advanced more than two weeks earlier on average. "The magnitude of the change is what surprised me most," Høye says.
Such advances are tied to the increasingly earlier snowmelt observed in Greenland over the past 10 years. As the climate warms further, Høye notes, snowmelt could come even sooner. Or not. "The overall predictions for the future of the area is of a more maritime climate, particularly warmer temperatures and increased precipitation during winter," Høye says. "Since the precipitation is likely to fall as snow this could mean either earlier or later timing of snowmelt."
He says scientists will continue to monitor such thawing changes, which could affect the timing of the entire ecosystem. "Since not all species respond equally strongly, [the accelerated snow melt] may cause interacting species to get out of synchrony, leaving consumers with more limited resources," Høye says. Arctic species—including plants that can live a century or more—may soon wish such springs forward might fall back.