Genetic diversity of Lithuanian populations of Juniperus communis L. in relation to abiotic and biotic factors

Juniperus communis L. is increasingly threatened in many parts of Europe, including the Baltic region. Our present study was aimed at evaluation of genetic diversity of J. communis populations of Lithuania. Fourteen selected populations differed in geography and habitats (coastal brown dunes covered with natural Scots pine forests, further referred as B; J. communis shrubs, F; transition mires and quaking bogs, D; subcontinental moss Scots pine forests, G; xero-thermophile fringes, E). Molecular variance was analyzed among populations (140 individuals, in total), employing 14 Inter Simple Sequence Repeat (ISSR) markers. Percentage of polymorphic loci differed between populations belonging to the different habitat type, being the highest for population representing habitat F (68.2%) and the lowest for populations D (42.9%). The data demonstrate the possibility to underestimate or overestimate this parameter if some habitat populations are bypassed. Means per population of Nei‘s gene diversity and Shannon‘s information indexes, were 0.158 and 0.239, respectively. Significant correlation between genetic and geographic distance of populations of J. communis was documented by Mantel test. Bayesian analysis of ISSR data has separated populations of Southern Lithuania from Northern part. Juniperus communis populations representing different habitats showed moderate interpopulation variance at ISSR loci. In ISSR-based dendrograms, individuals were correctly allocated to populations, even in case of populations growing in 0.5 km vicinity (habitats D and G). Among all populations the most distinct one was representing habitat of J. communis shrubs (F) protected by EUNIS. Principal coordinate analysis of weighted averages of Ellenberg’s indicator values (EIV) for herbaceous species, separated populations according to habitat type, while the same type analysis of ISSR data allowed distinguishing E habitat populations from populations of all other habitat type but G. Our study shows that on the local (Lithuanian) scale, molecular variance between populations of J. communis at ISSR loci might be related to habitat type. For evaluation and preservation of diversity of J. communis, different assessment methods should be included and management strategies should be directed in the way to retain variety of habitats encompassing both widely spread and less common ones.