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環境的確率性   kankyōteki kakuritsusei
environmental stochasticity


Die Raten demographischer Ereignisse in einer Population schwanken global im Laufe der Zeit.

Remember that demographic stochasticity refers to the inevitable variability in actual population growth rate that occurs even if the population vital rates (expected rates of survival and reproduction) don't change from one season to the next. Environmental stochasticity refers to the variability in population growth rate that occurs because vital rates differ from one season to the next. Making an analogy with evolutionary processes may help: Demographic stochasticity is like genetic drift. It is non-directional and non-deterministic. Environmental stochasticity is like a variable selection pressure. In any one generation there is a directional change and it is deterministic. It would be very useful if we could tease apart these two stochastic influecnes on population dynamics so that we could more accurately assess their effect.


University of Connecticut, Ecology and Evolutionary Biology

Copyright 2012 DIJ