Figure 2.

(a) Forecast proficiency as a function of how far into the future forecasts are made, for different levels of uncertainty in the growth rate parameter [CV(r)] of the predictive model, and uncertainty in the initial population size [CV(N₀)] of the predictive model. Also shown is the effect of the presence or absence of demographic stochasticity in the true dynamics. The y-axis shows average forecast proficiencies across replicates. The horizontal purple dashed line is the forecast proficiency threshold (arbitrarily 0.5), the time at which forecast proficiency crosses this threshold is the forecast horizon. (b) The effect of uncertainty in the rate of environmental change [CV(K_step)] relative to uncertainty in initial conditions, in the absence of demographic stochasticity.