Figure 2.

Multivariate variograms of environmental variables as a function of buffer size. The envelope corresponds to the 95^th and 5^th quantiles of the distribution of 10000 variograms obtained after random permutations of the environmental data. Squares represent significant values, i.e. values below the 5^th quantiles or above the 95^th percentile. The vertical line corresponds to the distance beyond which the variogram is not interpretable, i.e. half the maximum distance between villages. The last graph shows a histogram of hamlet distances.