We may soon witness a vast decline in shorebird populations, say researchers in a new paper in Science. And the major cause to this is the usual suspect: climate change.
Usually more eggs get stolen from nests by predators in tropical areas, compared to other parts of the world. To avoid predators, each spring shorebirds migrate to the Arctic to lay their eggs, build nests and raise offspring over the period of just a few months. This, however, might not be their best choice anymore as the rates of daily nest predation in the Arctic have increased threefold over the last 70 years. The situation is similar in Europe, as well as in most parts of Asia and North America, where daily nest predation rates have doubled.
Upon studying 40,000 nests of 111 species across the globe, scientists are quite sure that the major cause to this is climate change. Changes in snow cover and increased temperature variability have great impacts on the survival of prey such as lemmings, which leaves foxes, snakes and lizards looking for alternative sources of food.
And as fewer shorebirds survive due to habitat deterioration or hunting, the rising pressure by predators may soon lead species like the Spoon-billed sandpiper near to extinction.
Tamás Székely, a co-author of the paper and a professor at the University of Bath, finds these insights highly troubling. “Changes in predator-prey interactions can lead to cascading effects through the food web with detrimental consequences for many organisms thousands of kilometres away,” he notes. “Migration of shorebirds from the Arctic to the tropics is one of the largest movements of biomass in the world. But with increased nest predation, the babies are no longer making this journey with their parents.”
Thus, while it is important to consider climate impacts on particular species, the chaning interactions between prey and predators are just as important. Robert Freckleton, a researcher in animal and plant sciences at the University of Sheffield, is worried about the speed of change in predation patterns over the last 20 years and how the situation might evolve as climate change gets more intense. “This is particularly threatening for this group of birds as large numbers of species are declining anyway — and many have formerly relied on the Arctic to provide relative safe breeding grounds,” he says.
As the climate continues to change, the Arctic may slowly transofrms from a “safe harbour for breeding birds” into an “extensive ecological trap for migrating shorebirds”, says another co-author of the study, Vojtech Kubelka.
According to Larry Niles, a biologist not involved into the study, while climate change is one of the critical challenges for shorebirds, even more fundamental is our apathy towards the tragedy happening in front of our eyes. And the only way to deal with this is to collectively acknowledge our responsibility and accelarate action on climate change.
