L., L. and L. are perennial, cold-adapted clonal shrubs distributed throughout Europe, northern Asia and North America. Due to their usage in food (berries) and pharmaceutical industry (berries and leaves), their natural populations are exposed to anthropogenic and other impacts that affect their genetic make-up. We analyzed 14 fragmentary distributed and small-sized peripheral populations of these species from the Balkans, which represents the southeastern-European marginal area of their wide European distributions, using RAPD molecular markers. The contemporary genetic patterns in all three species within the Balkans were generally similar, and in comparison to previous reports on populations of these species found in northward Europe, where they have a more continuous distribution, the levels of genetic diversity were more or less halved, genetic differentiation was several times higher, gene flow exceptionally low, and the expected prevalence of clonal individuals was lacking. The population dynamics of all three species within the Balkans was complex and distinct, and was characterized by a past admixture of individuals from discrete populations of the same species and interspecific hybridisation not only between and but also between and , the latter not being reported to date. Conservation measures suitable for preservation of presumably genetically distinct portions of the Balkans’ gene pools of studied species have been suggested, while the utility of interspecific hybrids in breeding programs and/ or in food/pharmaceutical industry is yet to be assessed. Vaccinium myrtillus Vaccinium uliginosum Vaccinium vitis-idaea V. myrtillus V. vitis-idaea V. uliginosum V. vitis-idaea

Invasive species Symphyotrichum lanceolatum (Willd.) G. L. Nesom is spreading uncontrollably along wet habitats as well as in disturbed ecosystems. All those habitats function as corridors that facilitate seed dispersal. One way to prevent the spread of invasive species is to know their reproductive ecology. The present study evaluates the potential for generative reproduction of S. lanceolatum and determines how different temperatures, amounts of nutrients, and light regimes, affect seed germination. Seeds collected from 13 natural populations were germinated at four fluctuating temperature regimes (15/6, 20/10, 30/15, and 35/20 °C). To test the influence of nitrate on seed germination, two KNO₃ concentrations were used (5 mM and 50 mM solution). For each treatment, three replicates of 30 seeds were placed in complete darkness or a 14 h photoperiod. The results showed that the germination increased with increasing temperature. The optimal temperature regimes were 30/15 °C and 35/20 °C with approximately 88% germination. The overall effect of KNO₃ on germination was positive. The concentration of 50 mM KNO₃ had a less stimulating effect compared to 5 mM KNO₃. Seeds showed sensitivity to lack of light during germination but were able to germinate in a significant percentage in such conditions. Considering that S. lanceolatum often occurs in disturbed sites, these results suggest that seed reaction to alternating temperature, nutrients concentration, and light can be determining factors that affect seed germination of this species and, thus, its spread.

The species Aster lanceolatus occupies a significant position in the world and European lists of invasive species. Its spreading potential is a hazardous factor to the biodiversity in many countries. There are no relevant data on the wider proportion of this species in the area of Belgrade. The sites of Aster lanceolatus are annual or pioneer communities along the water courses, abandoned and neglected areas, forest margins, moist meadows. The study areas are located near a choice of water courses in Belgrade. The aim of the study was to assess the species ecology and population density, synecological interrelationships among the coenobionts of the communities in which it occurs, and also to map its the habitats. The study of population density was performed on the supplemented and partially modified 'CPS SKEW' form, applied in West European countries, by the principle of squares. The species was determined by standard floristic method, and the species location by GPS system. It was concluded that Aster lanceolatus was dominant and wild at all study sites. The individuals and populations are especially numerous on the river islands Ada Ciganlija and Veliko Ratno Ostrvo, along the stream Kumodrsaki Potok and the Danube left bank, where the number of individuals per squares is above 1300 and the degree of coverage is 100%. Its spreading potential is conditioned by the species biology, and the expansiveness by climate changes, anthropogenic impacts and the competitive interrelationships.

St John's wort is one of the best known and used medicinal plants. The demands for St John's wort in Serbia is still supplied by the collection of native plants. Therefore it was necessary to examine the concentration of heavy metals in the soil and in plant material on serpentinites and to assess the potential safe harvesting and further utilisation of this plant species. The research was performed on three serpentinite sites in Serbia: Zlatibor, Divcibare and Goc. The main soil types were determined and the contents of 7 chemical elements were analyzed in the soil and in the plant material. It was determined that the soils of all three localities had increased concentrations of nickel, chromium and manganese. The St John's wort plant material (leaves) showed the increased concentrations of iron, nickel and chromium. It was concluded that St John's wort was a tolerant species regarding the heavy metal content, and it was recommended to avoid its harvesting on the investigated localities.