Some Aspects of Population Structure In The Short-Term Cycle Of The Brown Lemming In Northern Alaska

Abstract

The phenomenon of cyclic fluctuations in animal numbers at arctic and subarctic latitudes, in the northern hemisphere, has provided the focus for much research and theoretical discussion on control mechanisms in natural populations. Whether one has in mind the short-term cycle with intervals of three to four years at tundra latitudes or the long-term cycle with intervals of nine to ten years at boreal-forest latitudes, the cyclic character of the fluctuation pattern has been generally accepted as a fact. This has led to at least two assumptions implicit if not expressed in the abundant writing of the last few decades on this subject. First, the cycles are so definite as to indicate that within the given community system there are biological variables, other than the animals whose fluctuations expose the cycles, which are significantly correlated if not causally related with those cycles. Second, the cycles are sufficiently definite to...