Fig. 1.

The network of Mediterranean meadows in which only links with Goldstein distances smaller than the percolation distance Dp = 91 (see Fig. 5) are present. Nodes representing populations are roughly arranged according to their geographic origin. The precise geographic locations are indicated as diamonds in the background map. One can identify 2 clusters of meadows, corresponding to the Mediterranean basins (east and west), separated by the Siculo–Tunisian Strait. The size of each node indicates its betweenness centrality (i.e., the proportion of all shortest paths getting through the node).