Diel vertical migration and global climate change: a dynamic modeling approach to zooplankton behavior
Die! vertical migration by zooplankton has been studied extensively and is clearly an important mechanism that increases fitness of individuals exposed to predation (ZARET \& SUFFERN 1976, STICH \& LAMPERT 1981, LAMPERT 1989). Historically this adaptation has been difficult to model, in part, because of the multiple factors which presumably lead to this kind of behavior (McLAREN 1963, ENRIGHT 1977, JOHNSEN \& JAKOBSEN 1987, GuWICZ \& PIJANOWSKA 1988). Recent developments in modeling optimal patch choice when food availability, metabolic costs and predation risk vary among habitats provide a rather simple yet powerful tool for examining the behavior of animals (MANGEL \& CLARK 1988, CLARK \& LEVY 1988). Here we employ dynamic programming to examine the die! vertical migration behavior of zooplankton in lakes. We also demonstrate how such a model can be used to assess the potential responses of plankton to global climate change using a series of interactive lake models driven by output from general circulation models.