Fig. 5

Empirical distributions of the D statistic (in grey), calculated from 100 trees sampled using Bayesian MCMC inference. These are compared with five replicates of the null distribution of D generated by the randomisation procedure (red lines). In (a) the distributions were calculated using the “elevation” raster (as a resistance factor) and in (b) they were calculated using the “forests” raster (as a conductance factor). In both cases the least-cost path model was used. For visual clarity, discrete histograms were converted into density curves using a Gaussian smoothing kernel