Beavers have the ability to completely change landscapes. They gnaw through trees, build dams and flood new areas to create ponds, earning them the title of “ecosystem engineers”. But a northward migration of these hump-toothed builders worries the scientists, reports Hannah Osborne for News week.
A new report on beavers is part of the National Oceanic and Atmospheric Administration’s (NOAA) annual issue Arctic certificate. Comparing decades-old aerial photographs of a region in western Alaska with newer ones, the researchers found that the number of ponds created by beavers has doubled in the past 20 years. They found more than 12,000 ponds; There was not a single one in the same area in 1955, reports Alexandra Larkin for CBS.
“We didn’t know what we were going to find and were very surprised,” Ken Tape, an ecologist at the University of Alaska, told Oliver Milman for the Fairbanks Guardian.
“There are areas in Alaska where there were no traces of beavers 50 years ago, and now they seem to have been fed up with beavers,” he says. “It’s only a matter of time before they go further north. Given that this is likely to happen in the rest of the Arctic in Canada and Russia, you can imagine the magnitude of this change.”
Beavers can create shallow pools of water when building dams. This has increased all surface water in the area, which is cause for concern as these ponds are warmer than the surrounding ice, causing permafrost – the permanently frozen ground – to thaw. Permafrost is a critical carbon sink and its thawing has been releasing stored carbon dioxide and methane for years. News week reported.
Researchers noted a dramatic increase in surface water across the region, attributing around 66 percent of that increase to the beaver presence, reports CBS.
“These ponds absorb heat better, they change the hydrology of the area and the permafrost reacts to it,” Tape tells dem Guardian. “It accelerates the effects of climate change. When you realize what happened in western Alaska, it is likely to happen in northern Alaska too, it makes you pause.”
There is also an additional concern about how the reshaped landscape and waterways will affect Alaska’s indigenous communities. Beaver dams could affect aquatic food webs and fish populations, and make boat access difficult. Further research is currently underway to analyze how the beavers will affect the ecosystem and livelihood of the indigenous population, says Helen Wheeler, ecologist at Anglia Ruskin University in England, in a Explanation.
It is still unclear why the beavers spread northwards at all. It could be that the effects of a warming climate – like more lush vegetation – have made the region more habitable for beavers who Guardian reported.
It could also be a booming beaver population spreading north into predator-free zones, or a combination of both.
“[It] is not entirely clear, but we do know that beavers have a significant impact on the ecosystems they colonize, “says Wheeler.