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Gilles Gauthier shares the findings of a project looking at the effect of climate change on tundra wildlife and how researchers from seven circumpolar nations took a closer look at the Arctic food web.

 

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Podcast Transcript: Gilles Gauthier

FRENCH VOICEOVER: Ce podcast a été enregistré à l'Année polaire internationale 2012.

ENGLISH VOICEOVER: This podcast was recorded at the International Polar Year 2012 Conference.

FRENCH VOICEOVER: IPY 2012.

ENGLISH VOICEOVER: IPY 2012.

ENGLISH VOICEOVER: From knowledge to action.

FRENCH VOICEOVER: De la connaissance à l'action.

HOST: For many years polar researchers assumed that what kept the Arctic food web in balance was at the bottom of the food pyramid – what most of us would call plants and rodents. But then, as part of a project looking at the effect of climate change on tundra wildlife, researchers from seven circumpolar nations took a closer look at the Arctic food web. They discovered that predators have a much more important role to play in keeping the Arctic ecosystem in balance than was previously thought. Dr Gilles Gauthier from the University of Laval was one of the researchers on the project, which was called Arctic WOLVES. He's here to tell me all about it.

00:57

HOST: So first of all, what does a food web look like when it's not in balance?

GUEST: Well when food webs are not in balance you can have some species that will become extremely abundant. For instance, if predators don't keep herbivores in check, they may explode and overgraze the system and cause damage, at least locally, to the vegetation.

HOST: What was the surprising discovery from Arctic WOLVES?

GUEST: One of the most surprising results was to find that predators seem to play a much more important role in controlling the food web – the tundra food web – than previously thought. For a long time the dominant view was that the plants' abundance was determining the abundance of herbivores, and that even though predators were present in the system, they were thought to be at low density and have little impact on the herbivores. On the contrary, we found through our project that predators were quite important and in fact were probably controlling several of the species – in particular the lemmings, the small rodents – in many locations, especially in northern Canada. And this was – even though there has been a suggestion before, I think our project was the first to provide really strong evidence that this indeed was the case.

02:28

HOST: And as you analysed your data, what was the reaction of your colleagues when you discovered that it wasn't quite as you had assumed?

GUEST: Well actually we're quite happy because this idea that predators could be more important than previously thought had been around for a few years. There was an increasing debate about, indeed, whether plants, as commonly assumed, were basically determining all the layers on top of them, or whether predators could actually play a role. And there was some piece of evidence before we started that started to suggest that predators could be important. So when we expanded at many sites and replicated the protocol to monitor the impact of these predators we were thrilled when we saw indeed that in many cases we were finding the same patterns in different locations.

03:26

HOST: Wow. And so were there other unexpected discoveries that you made as you were tracking these predators?

GUEST: Well the question came as how these predators can maintain themselves throughout the year because some of these predators, they have to live of course in the Arctic year-round. We're talking here species like the arctic fox, for instance, among mammals, or the snowy owl among predatory birds. We know in the summer the tundra is very productive. There's lots of animals – especially migratory birds for instance – that come up there. There is lots of food for these predators. But the winter is a different story of course because many of these animals, the insectivorous birds or some of the herbivorous birds like the geese, they leave the area. The lemmings are still there, but of course there is the snow in the winter that makes them harder to catch. So it's a very difficult period for the predators. But one of the things that we find is that many of these predators that stay in the Arctic – the fox, the owl – they actually leave the tundra and go on the sea ice for extended periods of time. That had been suspected, and actually there was anecdotal evidence for the fox, and we strengthened this evidence with new data. But for the owls that was a complete surprise. Nobody had thought that these magnificent birds would leave the tundra and go on the sea ice. But that's what we find, that in eastern North America – in Nunavut – many birds spend up to three, four months over the sea ice feeding on sea birds that winter in polynyas in the sea ice at high latitudes. So that was a very unexpected and very interesting result that we found.

05:23

HOST: What about traditional knowledge? How did that factor into the work you were doing? You talked about anecdotal evidence and –

GUEST: Well that's one of the examples with the fox, for instance. The arctic foxes are very important animals for northerners. I mean it's been trapped for a very long time. And there was some work done by one of my colleagues on the fox and the traditional knowledge, and people mentioned that that has been known, of course, by Inuit for a long time that fox were traveling on sea ice in the winter, were using, for instance, carcasses left by polar bears to feed. And even these people thought of two kinds, so to speak, of foxes: some that stay on the land all winter, some that went on the sea ice all winter. And in fact some of the radio tracking that my colleague did, they found pretty much what the people had told them, that some tended to stay on the land all the winter – so they tend to be land specialists – but others in fact will move for an extended period of time on the sea ice. So this kind of specialization among individuals was completely unknown to scientists.

06:39

HOST: How do you expect climate change to affect the food web in Canada now that you've seen these animals go on the sea ice? Do you anticipate any changes?

GUEST: These findings certainly have major implications for the impact of climate change on the tundra food web and the tundra wildlife because we know that some animals will expand northward. For instance, we're talking of the foxes. We know there's another species of fox – the red fox – that inhabits rather the boreal forests in southern Canada, but this species is expanding northward and invading the tundra as we speak. And the appearance of new predators could create – have a major impact on the food web since we've shown indeed that these predators are quite important. For instance, if functional – if there were very few functional predators, predators that were unimportant, that would mean that even if we add new animals, this would have little effect on the food webs, new species. But instead our results suggest that these new predators could have a major impact on some of the prey, and perhaps, for instance, shorebirds we know is a group of birds that are declining nowadays. We think that predations during the summer could be a factor. So if new predators appear or increase in abundance, that could mean a more difficult time ahead for these poor species.

HOST: It's fascinating work. Thank you for talking to me.

GUEST: Thank you.

08:19

HOST: That was Dr Gilles Gauthier. He was one of the researchers working on a project studying the effects of climate change on tundra food webs. The international research project was partially funded by the Government of Canada. You can hear more podcasts or watch video from the International Polar Year Conference at aandc.gc.ca. Or you can find this podcast at iTunes. Thanks for listening.

 

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