Cohort Variation in Reproduction and Survival: Implications for Population Demography

摘要: In two different species of cervid, red deer (Cervus elaphus) and moose (Alces alces) pronounced cohort differences in fitness have important demographic consequences. particular, where the environmental conditions into which a is born permanently affect reproduction survival, even if ameliorate later life, populations may fluctuate. Although variation survival both on Isle Royale, USA, Rhum, Scotland, has been attributed to nutritional status during period early development, there are marked contrasts underlying causes at birth. moose, was related density-dependent changes food availability, while density-independent, weather, factors determining onset spring grass growth influenced reproduction. However, development do not persist they unlikely significant affects lifetime reproductive success population fluctuation. For example, although breeding Norwegian varied relation animals were able compensate for retarded acheive large adult size maximum potential. The available evidence suggests that, supply limited by random stochastic processes, fluctuation likely be small compared with long-term climate like predicted global warming.