Role of predation in short-term population fluctuations of some birds and mammals in Fennoscandia.

摘要: We tested the hypothesis that synchronous fluctuations in small game species boreal Fennoscandia are caused by varying predation pressure. The main prey of predators cyclically superabundant voles. Small (alternative prey) rare compared to following 4 predictions were checked: (1) Predators should shift their diet from alternative as decline. — This was confirmed using data on red fox (Vulpes vulpes L.) diet.; (2) mortality rate be inversely correlated abundance prey. true for mountain hare (Lepus timidus rates and nest black grouse (Tetrao tetrix L.).; (3) total consumption all at least equal critical losses during a decline year. A tentative estimate predator amounted 10 times hare.; (4) absence synchrony between boreonemoral region associated with more diverse predators. case diets throughout Sweden. Although confirmed, we could not necessarily exclude other hypotheses involving changes quality or quantity plant food.