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The Khanka Lowland forest-steppe is the most eastern outpost of the Eurasian steppe biome. It includes unique grassland plant communities with rare steppe species. These coenosis have changed under the influence of anthropogenic activity, especially during the last 100 years and included both typical steppe species and nemoral mesophytic species. To distinguish these ecological groups of plants the random forest method with three datasets of environmental variables was applied. Specifically, a model of classification with the most important bioindices to predict a mesophytic ecological group of plants with a sensitivity greater than 80% was constructed. The data demonstrated the presence of steppe species that arrived at different times in the Primorye Territory. Most of these species are associated with the Mongolian-Daurian relict steppe complex and habit in the Khanka Lowland. Other species occur only in mountains in Primorye Territory and do not persist in the Khanka Lowland. These findings emphasize the presence of relict steppe communities with a complex of true steppe species in the Khanka Lowland. Steppe communities exhibit features of anthropogenic influence definitely through the long land use period but are not anthropogenic in origin. The most steppe species are located at the eastern border of distribution in the Khanka Lowlands and are valuable in terms of conservation and sources of information about steppe species origin and the emergence of the steppe biome as a whole. [ABSTRACT FROM AUTHOR]

The green alder Alnus alnobetula s. l., a widely distributed subarctic-alpine shrub species, has been studied using three chloroplast DNA regions: trnH-psbA, trnS-trnG, and psaA-trnS. In addition, new chloroplast primers coding the trnT-GGT cpDNA regions and five cpDNA microsatellite loci (cpSSR) have been developed for this species. The population subdivision is very high (Nst = 0.869, Gst = 0.807, Fst = 0.883), suggesting a distinct phylogeographic structure (Nst > Gst, p < 0.0001) and a sharp contrast between the haplotype-rich eastern part of the species range and the almost completely uniform western part (Siberia, Ural). According to a phylogenetic analysis, the common haplotype of A. alnobetula subsp. fruticosa in the western part of the range originated from northeastern refugia (West Beringia) as a result of interglacial recolonization, including bottleneck events. Three highly divergent cpDNA lineages of green alder that have been resolved in the Russian Far East are largely concordant with A. alnobetula subsp. kamtschaticа, A. alnobetula subsp. mandschurica, and A. alnobetula subsp. maximowiczii. The populations of Sakhalin Island are divided into three phylogeographic groups (southern, central, and northern) corresponding to the different floristic zones and different subspecies. The green alder populations from central Sakhalin have a haplotype-rich composition including different genetic lineages that confirm the existence of a hotspot of genetic diversity in this part of the island. [ABSTRACT FROM AUTHOR]

Rhododendron brachycarpum is an ecologically important tree species with a narrow, fragmented geographic range in East Asia. R. brachycarpum is distributed primarily in Korea and Japan, with two small isolated populations in the Russian Far East. We obtained 124 samples from seven populations of R. brachycarpum, representing all geographical regions of its entire natural range, and we utilized microsatellite markers to estimate the level of genetic variation within and between populations. A total of 200 alleles based on 14 nuclear microsatellites loci were identified. High diversity (He = 0.556–0.626) was observed in populations from Korea and Japan. In contrast, in peripheral populations from Russia diversity was quite low (He = 0.100–0.369) with a high coefficient of inbreeding (FIS = 0.471–0.526). Strong population differentiation (FST = 0.356) and clear distinction among the geographical groups (FCT = 0.227) were revealed. Bayesian clustering and principal coordinate analyses indicated that two Russian populations, Sikhote-Alin and Iturup Island, represent extremes of two different migration routes, with one derived from the mainland and one from Japan. [ABSTRACT FROM AUTHOR]

The vast territory of East Asia, including southwestern Beringia, is considered to have been almost ice free during the Pleistocene. Cold-resistant flora may have persisted in this region expanding or contracting its range during the climate cooling. Only a few plant genera have been studied with a sampling area across their entire geographic range in East Asia; therefore, the understanding of the biogeographic history of alpine flora in this region remains limited. In the present study, genetic variation and population structure in 21 populations of the alpine shrub Rhododendron aureum across its range in East Asia were assessed using 18 microsatellite loci. Phylogenetic analyses revealed three main genetic groups: Siberia, Northeast, and North Pacific. According to the geographical pattern of genetic diversity, the North Pacific group includes populations from Kamchatka, south of Russian Far East, and territories close to central Japan. This group is the most diverse and likely diverged earlier than the Siberia and Northeast groups. Ecological niche modeling predicts range expansion of this species during the period of cooling and, together with demographic history, suggests that the divergence between the three main genetic groups predated the Last Glacial Maximum. Similar to other cold-resistant species such as Larix sibirica and Juniperus communis, the pattern of genetic diversity of R. aureum supports the survival of the species at high latitudes during the Pleistocene with limited contribution of the southern populations to expansion of the species range to the Northeast region and Siberia. [ABSTRACT FROM AUTHOR]