Wolves and Moose – Unexpected Connections

Ambience: wolves

JM: The study of ecology sometimes reveals the interconnectedness of different parts of an ecosystem that seem to have no obvious connection. For example – you wouldn’t think that wolves could have an influence on the number of trees in a region, but they do. I’m Jim Metzner, and this is the Pulse of the Planet. Rolf Peterson is a Professor of Wildlife Ecology at Michigan Tech University. He’s been studying the ecology of Island Royal in Lake Superior. Wolves arrived there about fifty years ago and began preying on moose.

RP: “When we started almost 50 years ago, the key question was what impact do wolves have on the moose population, but as time has gone on, I guess we’re more interested in what’s the significance of having wolves for the entire ecosystem because everything wolves do sort of indirectly affects everything else. Maybe the most intriguing single finding is that the trees on Isle Royale fluctuate in their own growth patterns depending on how many wolves there are. So, the wolves are indirectly affecting tree growth because wolves affect the number of moose, and the moose eat trees. And so, you can actually see the ebb and flow of the wolf population by counting tree rings and measuring the ring width. The dynamics of moose and wolves have been really dramatic. They don’t just stay stable. We’ve had major fluctuations in moose and wolves, and when moose especially go up and down, they affect the vegetation that they eat, which is forest trees. And so, if moose are very numerous, trees don’t grow as well because they’re losing a lot of their foliage to moose. Conversely, when moose are rare, trees grow better. So the role of wolves in influencing fluctuations of moose actually shows up in the trees.

JM: We’ll hear more on moose and wolves in future programs. Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.

Wolves and Moose - Unexpected Connections

You might not expect the wolf population to effect the number of trees in an ecosystem - but it does.

Air Date:09/23/2013

Scientist:

Transcript:

Wolves and Moose - Unexpected Connections

Ambience: wolves

JM: The study of ecology sometimes reveals the interconnectedness of different parts of an ecosystem that seem to have no obvious connection. For example - you wouldn't think that wolves could have an influence on the number of trees in a region, but they do. I'm Jim Metzner, and this is the Pulse of the Planet. Rolf Peterson is a Professor of Wildlife Ecology at Michigan Tech University. He's been studying the ecology of Island Royal in Lake Superior. Wolves arrived there about fifty years ago and began preying on moose.

RP: "When we started almost 50 years ago, the key question was what impact do wolves have on the moose population, but as time has gone on, I guess we're more interested in what's the significance of having wolves for the entire ecosystem because everything wolves do sort of indirectly affects everything else. Maybe the most intriguing single finding is that the trees on Isle Royale fluctuate in their own growth patterns depending on how many wolves there are. So, the wolves are indirectly affecting tree growth because wolves affect the number of moose, and the moose eat trees. And so, you can actually see the ebb and flow of the wolf population by counting tree rings and measuring the ring width. The dynamics of moose and wolves have been really dramatic. They don't just stay stable. We've had major fluctuations in moose and wolves, and when moose especially go up and down, they affect the vegetation that they eat, which is forest trees. And so, if moose are very numerous, trees don't grow as well because they're losing a lot of their foliage to moose. Conversely, when moose are rare, trees grow better. So the role of wolves in influencing fluctuations of moose actually shows up in the trees.

JM: We'll hear more on moose and wolves in future programs. Pulse of the Planet is made possible by the National Science Foundation. I'm Jim Metzner.