Recruitment variability and populations dynamics

• Ottar N. Bjornstad

Abstract
Variability in the recruitment into populations is a key parameter in population ecology. It is a critical determinant of extinction risks, population viability and population regulation. I propose to study recruitment variability and its consequences on population dynamics from a combined empirical and theoretical perspective. In the project I will (1) bring together stochastic and density-dependent theories of populations dynamics, (2) develop statistical methodology dedicated to the study of abundance data, (3) estimate the magnitude of recruitment variability through time series analysis, and (4) quantify the effects of variability on population dynamics through stochastic simulation. I focus on regulation in populations that are governed by age- or stage-structured interactions. That is because many economically important populations that exhibit recruitment variability (such as fishery stocks) are governed by structured interactions. The dynamic effect of the variability will vary greatly depending on the relative and absolute strengths of the intra- and inter-stage interactions. In accomplishing the 4 objectives I will increase our understanding of the interaction between density-dependent and density-independent forces. I will quantify the importance of stochastic events in shaping the dynamics of real populations, and improve on the analytical tools to deal with recruitment variability. The proposal is for a two-year postdoctoral position to start in September 1998.