Figure 2.

Reparametrized model including one non-significant parameter estimate: influence of gerbil abundance on plague persistence. This parameter cannot be shown to be different from neither zero nor the joint value for invasion and persistence. (a,b) Probability of plague presence (ordinate), given past great gerbil abundance (abscissa) and extent of plague in neighbouring squares. Solid lines correspond to ; dashed lines correspond to and 0.8, in increasing distance to the abscissa. (c,d) Corresponding contour plots showing probability of plague presence, including data from a randomly selected imputation. Large points denote imputed presence of plague, small points denote imputed absence of plague.