Genetic Monitoring of Alnus glutinosa Natural Populations Using Two Generation Cohorts

The genetic diversity of populations is the ultimate source for adaptation and survival under changing environmental conditions. Genetic monitoring of temporal genetic diversity changes in autochthonous forest tree populations of key ecosystems species allows us to predict and mitigate potentially harmful changes of forests adaptability. The aim of the present study was to assess the genetic diversity of autochthonous protected A. glutinosa populations, to compare the genetic diversity between maternal and progeny generations, in a distribution area that is known to harbour extensive genetic diversity, and to assess if there is an impact on genetic diversity when forest management practices to promote natural regeneration of mature stands are introduced. The genetic diversity of ten A. glutinosa populations from Lithuania was studied using 20 nuclear SSR primers. In total, 597 individuals (300 juvenile and 297 mature trees) were investigated. In half of the studied black alder GCUs, forest management to promote natural regeneration was carried out. The present study revealed high genetic diversity (average population Ar was 5.77, Ho and He-0.70) and low, but a significant population differentiation of studied A. glutinosa populations. The lack of significant genetic differences among different generations (population cohorts), is a strong indication that the black alder GCUs in Lithuania form an excellent platform for the protection of the species' genetic diversity in the country.