Temporally structured density-dependence and population management

In English We used a simple discrete-time population model to investigate how temporally structured density-dependence influences a population's response to loss due to harvesting. We assumed that reproduction is a relative discrete event in time, followed by density-dependent mortality and then harvesting, or followed by harvesting and then density-dependent mortality. Such an ordering of events in time may have profound influences on the dynamics of the population. The extra mortality due to harvesting may either be additive or compensatory depending on the strength of the density-dependence and the ordering of events. Population stability is also strongly affected by the temporal structure of density-dependence. Moreover, the yield and the (unconstrained) optimal harvest rate will vary depending on when harvesting occurs in the annual cycle. We argue that a correct identification of the temporal structure of density-dependence may be of great importance for understanding population dynamics in general and population management in particular.