Fig. 2

Number of alleles (black line) and allelic richness, Ar (red line) per sampling site for (a) Dataset 1 (6 microsatellites) and (b) Dataset 2 (15 microsatellites). Samples are ordered from north to south. In graph a), Ar experienced an increasing N-S trend (τ = 0.296, P = 0.00045) but not the number of alleles (τ = 0.153, P = 0.074); whereas in graph b), neither number of alleles nor Ar showed any sort of geographic trend (τ = 0.243, P = 0.1721; and τ = 0.0543, P = 0.7888, respectively)