The effect of stochastic variation strength.

<p>The effect of pink stochastic variation on outbreak dynamics at different environmental variances. Left panels (A)–(C): variations affect pathogen growth rate <i>r</i>_p. Right panels (D)–(F): variation affects 50% infective dose <i>ID</i>₅₀. Top panels (A) and (D): cumulative incidences. Each dot represents a single outbreak, the number of which varies between simulations. The lines show a marginal kernel density estimate of peak areas. Panels (B), (C), (E) and (F): number of peaks and minimum values of healthy host density. Each dot represents a single simulation run. The lines show a smoothing spline fit to the points. In all simulations the spectral exponent <i>γ</i> = 1, i.e. pink noise. Colours red, black, and blue show results on rapid, intermediate, and slow immunity loss rates, respectively. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145511#pone.0145511.t001" target="_blank">Table 1</a> for model parameters.