There is no evidence to demonstrate that the distinct genetic structure of the six individuals was caused by management according to ISS. It is more likely a result of unsampled adult genotypes, no matter if the studied saplings originated from the same or different mast years. Some studies of forest trees used FST to evaluate differences between two temporally divergent populations, i.e. different developmental phases ( Maghuly et al., 2006 and Bilela et al., 2012). However, FST indicates subpopulation differentiation because of restricted gene flow among subpopulations and is not meant to quantify temporal changes. In this study, we used a
simulation procedure to test whether forces other than drift and sampling error contributed to differentiation of allele frequencies between two consecutive generations of beech. Trametinib 17-AAG mouse Although erroneous, we also used conventional FST analysis for comparison. Temporal changes in allele frequencies caused by forces other than genetic drift and sampling error between adult cohorts and saplings were detected in both the managed
stand at three loci and in the old growth stand at two loci. Apart from the drift and sampling effect, management could have caused some changes in allele frequencies between the generations in the managed stand but could not explain all significant differences in allele frequencies because these were observed in both the managed and old growth stands, having locus Fs6 in common. Directional selection could have caused the observed changes but none of the loci were identifies
to be outliers, making selection an unlikely cause of the temporal changes in allele frequencies in this study. Beech is currently expanding in Slovenia (Poljanec et al., 2010) and reciprocally replacing silver fir, particularly in the Dinaric silver fir-beech forests (Boncina et al., 2003 and Diaci et al., 2010); both processes might contribute to the differences in allele frequencies between the adult and offspring generations in our study. Tangeritin Only some of the individuals from the studied regeneration centres will be recruited into the canopy of the future stand; which ones will be greatly influenced by light conditions (Petritan et al., 2007) governed by gap size and canopy structure (Rozenbergar et al., 2007 and Nagel et al., 2010), forest type, soil pH and basal area (Klopčič and Bončina, 2012). Yet our results show that genetic diversity and possibly structure of the recruited individuals will most likely be similar to that of the adults in both studied stands, at least according to neutral markers used in the study. In the presented case study, we examined the potential effects of ISS on genetic diversity and structure of a European beech stand by (i) comparing managed stand to old growth beech stand and (ii) comparing two successive generations in both managed and old growth stands.