Temporally structured density-dependence and population management

We used a simple discrete-time population model to investigate how temporal ly structured density-dependence influences a population's response to loss due to harvesting. We assumed that reproduction is a relative discrete eve nt in time, followed by density dependent mortality and then harvesting, or followed by harvesting and then density-dependent mortality. Such an order ing of events in time may have profound influences on the dynamics of the p opulation. The extra mortality due to harvesting may either be additive or compensatory depending on the strength of the density-dependence and the or dering of events. Population stability is also strongly affected by the tem poral structure of density-dependence. Moreover, the yield and the (unconst rained) 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 understandi ng population dynamics in general and population management in particular.