What determines variation in amplitude and periodicity of population outbreaks remains a mystery. Experiments to stop cyclic dynamics and comparisons of cyclic and noncyclic populations provide some understanding but both reproduction and mortality must be considered. In addition to high reproductive rates and density-related mortality from predators, pathogens or parasitoids, other characteristics include transgenerational reduced reproduction and dispersal with increasing-peak densities, and genetic similarity among populations. Even though cyclic species have very different life histories, similarities in mechanisms related to their dynamics are apparent. For almost a hundred years, innumerable studies have probed the causes of cyclic dynamics in snowshoe hares, voles and lemmings, forest Lepidoptera and grouse. Population cycles are one of nature's great mysteries. Population cycles: generalities, exceptions and remaining mysteries
Population cycles: generalities, exceptions and remaining mysteries.
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