Using a long-term data set on the fluctuations of a reintroduced Swiss population of ibex we estimated the parameters in a stochastic population model with theta-logistic density regulation, and how the environmental stochasticity was related to different climate variables. Our aim was to examine quantitatively the relative effects of variation in parameters describing the expected dynamics and the environmental stochasticity as well as the uncertainties in them for the development of reliable population projections. The specific growth rate r1 was 0.14. Density regulation mainly happened close to the carrying capacity K, indicating that the commonly used assumption in population ecology of loglinear density regulation is not always valid. Annual variation in the point estimates of the environmental stochasticity was correlated with winter climate. Uncertainties in parameter estimates were high, especially in the estimates of density regulation and r1. In order to examine the dynamical consequences of the...