Fig. 2

a CO1 haplotype map showing the haplotype composition for G. fossarum at different sampling sites in the Sauerland region. The sizes of haplotype pie charts are scaled according to the numbers of sequences per site, which are given in Table 1 together with the sub-catchment association of sampling sites. Red stars indicate water reservoirs. Red highlighted sampling sites indicate that microsatellites were analyzed at these sites. All private low-frequency haplotypes are colored in black, or in gray if more than one private haplotype was found at the respective site. Colored contour lines illustrate GENELAND groups, named A–H. b Bar chart showing the frequency of significant and non-significant F _ST values for microsatellites (msat) and CO1 sequences