Can barnacle geese predict the climate?

(Netherlands Institute of Ecology; Photo: Thomas Lameris; 18 April 2017)

The breeding grounds of Arctic migratory birds such as the barnacle goose are changing rapidly due to accelerated warming in the polar regions. They won’t be able to keep up with this climate change unless they can somehow anticipate it. A research team from the Netherlands Institute of Ecology (NIOO-KNAW) employed computer models to assess the future of the geese and their young.

It’s the time of year when barnacle geese and many other migratory birds prepare to depart for their breeding grounds above the Arctic Circle. From their wintering grounds in the Netherlands, the geese fly all the way up to the Barentsz Sea in northern Russia, where they should arrive just as the snow has melted. But in the polar regions, the climate is warming much more rapidly than in more temperate areas like the Netherlands — a phenomenon known as ‘Arctic amplification’.

It’s hard enough for humans to get to grips with the accelerated warming, let alone for barnacle geese, as an earlier NIOO-led study showed. After all, how can they tell from their wintering grounds if the snow has begun to melt thousands of kilometres away? So is it possible for the barnacle geese to advance their spring migration nonetheless, to predict climate change?

First study, fewer young

Ecologist Thomas Lameris and his fellow researchers from NIOO, and also the Swiss Ornithological Institute among other institutions, have tried to find the answer. “This is the first study that tests if migratory birds are in any way able to adjust their timing to the accelerated warming in the polar regions. We used a model to show that the availability of enough edible grass to build up reserves for their journey is not a problem for the barnacle geese. It’s the unpredictability of the climatic changes in their breeding grounds that spells trouble for them.”

If the geese continue to mistime their arrival, their reproductive success will be reduced. Lameris: “They miss their optimal breeding window and the peak in local food abundance, so fewer goslings will survive.” Some compensation for this comes from the fact that as well as starting earlier, the breeding season is becoming longer. This gives the goslings more time to grow. But that’s not enough.

To establish the barnacle geese’s potential for anticipating climate change, the researchers built a model that…….

Read more

Advertisements