Andrew R. Jacobson, Antonello Provenzale, Achaz von Hardenberg, Bruno Bassano, and Marco Festa-Bianchet. 2004. Climate forcing and density dependence in a mountain ungulate population. Ecology 85:1598–1610.

Appendix B. Figures of diagnostic tests on model residuals.

FIG. B1. Analysis of residuals from the stochastic Gompertz density dependence model (Eq. 3) applied to the 44-year data set of ibex population changes. (a) Model residuals. (b) Autocorrelation function of the residuals, with the Tong (1990) critical level shown (dashed line). (c) Cumulative distribution function of residuals, compared with a the normal CDF (smooth line).

FIG. B2. Analysis of residuals as in Fig. B1, but for the climate model, (Eq. 9) using average snow cover at Serrù.

FIG. B3. Analysis of residuals as in Fig. B1, but for the complete threshold model, (Eq. D.11) using Serrù climate data.

 

FIG. B4. Analysis of residuals as in Fig. B1, but for the final accepted threshold model, (Eq. D.13) using Serrù climate data.

Literature cited

Tong, H. 1990. Nonlinear time series: a dynamical system approach. Oxford University Press, Oxford, UK.