A major hypothesis to explain when population cycles should be present or absent is the difference between generalist and specialist predation. Specialist predation is assumed to be largely destabilizing while generalist predation should be stabilizing. Using examples from the Arctic, notably the parametrised differential equation model of Gilg et al. 2003 [Science, 302:866-868], designed to explain lemming cycles in Greenland, we show that the role of generalist predation is more nuanced. In particular, we find that (1) generalist predators can initiate population declines and (2) short cycles persist in the absence of specialists. We then discuss the specialist-generalist predator dichotomy and its usefulness for population cycles theory.

cycles; predator-prey; generalists; functional response; dynamics