Figure 4.

Cumulative directed degree distributions for both types of pond under different drought levels (i.e. fraction of dry ponds), and amphibian dispersal ability d (d=100 m (circles), d=500 m (squares), and d=1000 m (triangles)). The number of ponds with at least k links decreases following different functions. For drought=0.1, the best fit is an exponential distribution in all cases, p<0.001. For drought=0.5, the best fit is an exponential distribution for d=100, and truncated power-law in the rest of cases, p<0.001. For drought=0.9, the best fit is to a truncated power-law in all cases (except d=100 for dry ponds, for which the best fit is a power-law), p<0.001.