3.5 Indicators
Indicator classifications are shown in Figure 7. In summary, theΔH indicator detects reduction of genetic diversity within several populations (Figure 7a), but metapopulation systems buffer against some of these trends so that when metapopulations are considered – increase and decrease within separate subpopulations levels out (Figure 7b). This is not the case in all systems however, and theN e-indicator provides warning signals of low effective population sizes in 6 out of 10 systems studied (Figure 7b). The ΔF ST indicator shows that gene flow is significantly decreasing in the same metapopulation (Skåarnja 2) were we also observe ΔH and N e warning signals. However, the change of F ST reflects an expected reduction genetic exchange that is less than the proposed threshold value, i.e., the number of migrants between subpopulation is estimated to have been reduced by less than 25% over the monitoring period (Figure 7b).