During the 1950s-1960s, the Merkys river basin, the largest protected area of Lithuania, underwent severe anthropogenic regulations. Within the Baltic States, the genetic diversity of Phalaris arundinacea populations is unknown and how they might be affected by anthropogenic activities such as river regulation. The objectives of this study were to compare molecular parameters (SSRs or microsatellite loci) within and among populations from natural river fragments with populations from regulated river parts. Study populations have greater genetic diversity within, rather than among, populations. The upstream portion of the Merkys basin populations had lower genetic diversity compared with further downstream. The mean number of polymorphic SSR loci was lower for populations from regulated parts of the river basin compared with natural ones. Main principle coordinate analysis revealed populations of regulated rivers at marginal positions. Bayesian clustering showed that current populations are admixtures of 3 distinct genetic groups, based on STRUCTURE analysis (K = 3 groupings) in geographic subdivisions of (a) downstream populations (Varėnė, Verseka, Upper Grūda, Lower Grūda, Upper Merkys, Lower Merkys), (b) upstream populations (Upper Šalčia, Beržė, Lower Šalčia, Visinčia, Lower Šaltykščia, Nedilė), and (c) the 2 regulated sites in the distinct geographic area of Taurupis and Upper Šaltykščia.P. arundinacea in the Merkys river basin does not all belong to a single, random-mating population encompassing its tributaries or among populations across its geographic scales. In several instances, river regulation might impair the genetic diversity of P. arundinacea populations.

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.

The present study evaluated genetic diversity of Lithuanian populations of Lythrum salicaria in relation to parameters of riparian environment. Growing along Nemunas, Seaside and Lielupė river basins, 15 populations were examined using amplified fragment length polymorphism markers. Molecular data were related to the river basins, type of land use and cover, natural vice versa regulated fragments of the rivers. Population mean genetic diversity parameters were as follows: percentage of polymorphic loci (57.2), expected heterozygosity (0.183), polymorphismc information content (0.218). Mantel test revealed correlation (R2 = 0.0986, p = 0.01) between genetic and geographic distance of populations. Greater genetic diversity within, rather than among populations (ΦPT = 0.213) was observed. According to the Bayesian clustering, studied populations are admixtures of two gene pools. Analysis of molecular variance revealed significant differentiation between populations belonging to distinct river basins, between populations from natural vs. regulated fragments of the rivers.

Common juniper (Juniperus communis L.) is an important conifer from the ecological and economical point of view. In some areas of the distribution range, it is a widely studied species. Up till now insufficient attention has been paid to junipers growing in the Baltic countries where it is one of three natural conifers and important forest tree species. Recently, molecular markers-based diversity of Lithuanian populations of J. communis was determined, although related biological and ecological variables remain undisclosed. The present study is aimed at the evaluation of biotic and abiotic environment of J. communis according to plant species composition. Fourteen sites with J. communis were selected in the territory of Lithuania. At each site undergrowth trees and shrubs, herbaceous species, dwarf shrubs, and mosses were recorded and the abundance of each species was evaluated. Abiotic environment characteristics were obtained using Ellenberg's indicator values (EIV) of the plant species neighbouring junipers. In the sites with J. communis, 80 species of herbs and dwarf shrubs belonging to 18 families were registered. The largest variety of herbaceous species and dwarf shrubs (18-22 per site) was registered for sites representing xero-thermophile fringes. Species coverage data recorded in the sites in most cases allowed to group sites according to their habitats. Despite rather small territory of the present survey (latitude (N) 56°07'-54°11' , longitude (E) 21°06'-26°30'), the ranges of indexes for environment factors of juniper sites were rather wide: 6.0-7.3 for light, 3.0-5.8 for temperature, 3.7-5.3 for continentality, 4.2-7.8 for soil moisture, 2.7-7.4 for soil reaction, and 2.7-4.4 for soil nitrogen. Among the sites selected by us, the most contrasting in terms of EIV were locations representing coastal brown dunes covered with natural Scots pine forests and xero-thermophile fringes. Keywords INTRODUCTIONJuniperus species are substantial elements of present-day forests (Garcia et al., 2000;Adams, 2011) and some of them are on the border of extinction (Lima et al., 2010;Rumeu et al., 2011;Silva et al., 2011). This historically old genera is important for providing information about evolution of plants in Late Glacial period (Koller et al., 2005;Li et al., 2011, Veski et al., 2012. Juniperus contains economically valuable species used for medicinal purposes (Muto et al., 2008;Kusari et al., 2009), perfume industry (Lawrence, 1984, flavoring of food and alcoholic beverages (Maarse, 1991;Vichi et al., 2007). These circumstances point out the need of comprehensive knowledge about Juniperus species.Juniperus communis is widely distributed over the Northern hemisphere, growing in Europe and three other continents. Junipers have been examined by molecular and biochemical markers in various regions of their natural occurrence (Canary Islands, Greece, Germany, UK, Russia, Japan, China, Kazakhstan, Nepal, Ethiopia, Guatemala, Cuba, Mexico, Utah, Texas, etc. (Adams et al., 2003;Adams, 2011). Examination of variabl...

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