SACHA PFEIFFER, HOST:
For years now, scientists have been documenting the somewhat mysterious spread of a new species into the Arctic, beavers. They're sometimes called nature's engineers for the way they change the shape of streams and rivers and ponds. Those changes can accelerate the effects of climate change, since the warmth of the ponds the beavers create with their dams can thaw the frozen ground below. They may also be affecting the environment in other ways. Helen Wheeler is a wildlife ecologist at Anglia Ruskin University in the U.K. She's researching the impact of beavers on indigenous communities and local ecosystems in Canada. She joins us from Cambridge, England. Hi and welcome.
HELEN WHEELER: Hi.
PFEIFFER: Would you tell us a little more about beavers expanding northward? When did that start, and how big an influx are we talking about?
WHEELER: Sure. So the time scale of major increases in beavers is kind of over the last 15 to 20 years, I'd say. And we're seeing quite substantial changes. It really depends where you are, how substantial that change is. So, for example, in western Alaska, you can see from satellites the ponds that beavers are creating. They've said there's kind of a doubling in the number of beaver-related ponds in the last 20 years.
PFEIFFER: Do you know why this is happening?
WHEELER: There's two kind of major drivers that we think could be occurring. So it may be that beavers a long time ago were much more abundant in the Arctic and then during the fur trade declined. And then as the fur trade came to an end towards the end of the 19th century, we started to see them increase again. And then more recently, there's been a shift to maybe younger generations trapping beavers less. And so we might see them recovering even more. The other option is that beavers are actually expanding northwards more than they have in the past due to climate change. It could be that, for example, with shrubs moving further northwards under climate change, beavers are able to use those shrubs to build their dams and lodges. Or it could be that we've got longer periods without snow, which means there's longer for beavers to forage in the summer.
PFEIFFER: I understand you're interested in research questions about how these beavers are impacting people who live in the Arctic and their local landscape. What have you found so far?
WHEELER: So at the moment, we're really looking to expand our research. One really important part of that is we're working on indigenous lands - has been to do a kind of full consultation as to what the research priorities are. And within that process, a number of concerns have definitely been coming up. Some of those concerns, for example, are around how this might impact fish, particularly in the last summer. There was beaver dams to the extent that there was no water downstream. And so there were no fish, and that was important subsistence fisheries for local people. There were also concerns around access, so the ability to get to important hunting and trapping areas could be affected by beaver dams, for example. And so beaver dams are potentially going to block passage through rivers. Or submerged beaver dams can be particularly dangerous because they can damage boats without being noticed. So there's particularly a concern which can affect people's ability to get to important hunting and trapping places, which, you know, has important impacts on culture, as well.
PFEIFFER: Are you hearing anything from the people who live there about how they deal with this or how they're trying to cope with it or push back?
WHEELER: One thing people are looking to is that culture around trapping and whether that can be a solution. I think there's thoughts about removing beaver dams to allow the fish populations to return and things like that. And so I think that's the questions people are really asking now - is how to deal with this problem.
PFEIFFER: In terms of your future research, what are the main, big, unanswered questions about this beaver phenomenon that you'd like to be able to answer?
WHEELER: Because so many things are changing in the Arctic at the same time, just understanding what's causing this is an open question in itself. So firstly, the causes and then the consequences. And those are the ecological consequences and then also the social consequences for people. So I'd say those are the first questions. And what that can help us do is help us provide that information so that people can make decisions about how they want to manage the challenges that this is creating, really.
PFEIFFER: That's Helen Wheeler, a wildlife ecologist and senior lecturer at Anglia Ruskin University in the U.K. Thank you very much.
WHEELER: Thank you. Transcript provided by NPR, Copyright NPR.
