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Animals of the boreal forest yclic fluctuations
of populations are more widespread than one might think at first.
Many forest insect populations, such as those of the spruce budworm of
the Canadian taiga, and the larch budmoth of Swiss Alpine forests, have
population irruptions which recur quite regularly, much to the dismay of
the forestry industry. In many parts of Europe and North America,
cockchafers and June bugs reappear regularly every three or four years.
Most well-studied of all population fluctuations, however, are the celebrated
oscillations of small mammals of the far North.
There are two classes of oscillations which have been observed. The first, among lemmings, voles (field mice), and their predators, is a three-to-five year cycle observed across large regions of northern Europe and America. The second involves hares and their predators in the forests of Canada, Alaska, and Siberia. In the boreal forests, cyclically fluctuating species include hare, lynx, coyote, marten, ermine, fox, muskrat, vole, and great horned owl. Although, as ecological communities go, the boreal forest community is simple, it nevertheless involves many interactions among the species. One way to see is by looking at the food web, a diagram which links a food species to the species which eats it.
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