Arctic Nature's Clock has Gone Haywire

 

Due to diminishing sea ice cover, spring is coming sooner to some plant species in the low Arctic of Greenland, while other species are delaying their emergence amid warming winters, says a study.

 

"The timing of seasonal events, such as first spring growth, flower bud formation and blooming, make up a plant’s phenology — the window of time it has to grow, produce offspring and express its life history. Think of it as “nature’s clock.” - says a study published in the journal Biology Letters and led by the University of California, Davis.

 

The study covers 12 years of observations at a West Greenland field site, about 150 miles inland from the Davis Strait. The site is near Russell Glacier, a dynamic front protruding from the massive inland ice sheet that covers most of the island. Each year from early May to late June, researchers looked daily for the first signs of growth in plots enclosing individual plant species.

 

They found that warming winters and springs associated with declining arctic sea ice cover created a mixture of speed demons, slowpokes and those in between. One racehorse of a sedge species now springs out of the proverbial gate a full 26 days earlier than it did a decade ago. This was the greatest increase in the timing of emergence the researchers have seen on record in the Arctic.

 

“When we started studying this, I never would have imagined we’d be talking about a 26-day per decade rate of advance,” said lead author Eric Post, a polar ecologist in the UC Davis Department of Wildlife, Fish and Conservation Biology who has been studying the Arctic for 27 years. “That’s almost an entire growing season. That’s an eye-opening rate of change.”

 

But other species are in no rush, despite the Arctic’s short growing season. Onset of growth for the gray willow has not budged, and a dwarf birch species is beginning its growth only about five days earlier per decade.