Botanica Lithuanica , Volume 17, Number 2–3

2011 m.

Two localities of Wolffia arrhiza were recorded in the southwestern part of Lithuania in 1998 and 2010. These plants grow in small insolated eutrophic water bodies with organic sediments in the inundated depression between hills dammed by beavers. The populations cover almost 100 % of the water surface, simultaneously forming communities of the Wolffietum arrhizae association. In Lithuania, these communities are not so rich in species as in neighbouring Poland, however, the species composition is very similar.

Keywords: Lemnaceae, Lemnetea, distribution, habitats, ecology, syntaxonomy.

Plants cultivated in gardens or other ornamental plantations possess no danger to the environment until they remain in cultivation; however, any plant that has escaped from cultivation should not be neglected because this process can be the start of species naturalization and future invasion. The investigations on alien plant species invasion to forests in the vicinity of communal gardens were conducted in June–August 2008.Six garden communities situated in Vilnius and its environs were selected for the research. Diversity of alien plant species was investigated in the selected study areas situated in the forest habitats outside the limits of the area of communal gardens. The aim of this research was to evaluate the diversity of alien plant species in the forest habitats in the vicinity of communal gardens and the relationship between spread intensity and distance from a garden. In all sampling plots arranged in the vicinity of the communal gardens, 56 alien plant species were registered. The number of alien plant species in the studied areas varied from 18 to 29. Statistically reliable negative correlation (r = -0.77, p < 0.05) was found between the number of alien plant species and the distance of sampling plots from the edge of communal gardens. This research revealed a high diversity of alien species in the vicinity of communal gardens, thus, they should be considered as an important source of alien and potentially invasive species.

Keywords: non-native plant species, forest habitats, coefficient of similarity, dispersal, frequency, naturalization, gardens, ornamental plants, Lithuania.

Diversity and ecological aspects of pyrenomycetes and loculoascomycetes from deciduous forest in Pavilniai Regional Park were studied. A total of 83 species of pyrenomycetes and loculoascomycetes, belonging to 14 orders were identified. Eleven fungal species were recorded for the first time in Lithuania. The studied fungi were found on various types of substrate of 17 woody plant species in three forest communities: Alno incanae-Fraxinetum excelsioris, Pruno padi-Alnetum incanae and Querco-Ulmetum campestris.

Keywords: fungi, pyrenomycetes, loculoascomycetes, diversity, host, substrate preference, Lithuania.

Coccoid green algae accounted for about 20 % of the total plankton algal diversity (688 species) in the small lakes and ponds of the Baltic Uplands. During the vegetation period, they made up to 49 % of total phytoplankton species number and up to 85 % of abundance in the separate lakes reaching the highest species diversity and abundance in summer. The diversity and abundance of coccoid green algae depended on lake morphometry, hydrological and watershed features as well as nutrient availability. The highest diversity of chlorococcoid algae was determined in shallow, overflowing water bodies surrounded by agrarian-urbanized landscape, the lowest diversity – in deep or rather deep lakes surrounded by forests and with dominant ground water inseeping. The highest species number of coccoid green algae, their relative contribution to phytoplankton community and total abundance were recorded in eutrophic with hypertrophy features shallow-planctonic lakes, the lowest – in mesotrophic (deep and shallow-macrophytic) ans shallow-swamp lakes. Coccoid algae frequently dominated in mesotrophic water bodies. Swamp lakes were characterized by specific flora of this group.

Keywords: Chlorococcales, phytoplankton, lake trophy, Lithuania.

The paper deals with the results of inventory of lichen-forming, lichenicolous and allied saprobic fungi from Kamanos State Strict Nature Reserve. A total of 171 species (of these 152 species of lichens, 16 lichenicolous and 3 non-lichenized saprobic fungi) were reported. Three lichenized species (Lecanora farinaria, Normandina acroglypta and Ochrolechia alboflavescens) and two lichenicolous species (Epicladonia simplex and Pronectria santessonii) were reported for the first time in Lithuania. Only one species of thre Red Data Book (RDB) of Lithuania – Arthonia venosa was recorded. Icmadophila ericetorum, RDB species previously reported from the Reserve was not refound.

Keywords: lichens, lichenicolous fungi, Lithuania, protected areas.

Anthropogenic transformation of natural systems creates opportunity for native and alien species of vascular plants with various ecological requirements to migrate and anchor the newly formed anthropogenic habitats. Comparative analysis of the composition of vascular plant species in abandoned quarry and natural forest indicated that overall botanical diversity of the territory increases considerably after anthropogenic transformation of the area. The character of vascular plant species distribution in the quarry was largely determined by the relief forms, mainly by the slope exposition. Route method used in this research in comparison with other available techniques allowed more impartial evaluation of the composition and frequency of flora components of the limited-size and orographically heterogeneous territories.

Keywords: anthropogenized territories, flora, quarries, frequency of plant species, Lithuania.

The applicability of two microscopy-based methods for virus enumeration was evaluated for the eutrophicated Curonian Lagoon. Total abundance of viruses determined by means of electron and epifluorescence microscopy ranged from 1.91 × 107 to 5.06 × 107 viruses ml-1 and from 72.81 × 107 to 141.88 × 107 viruses ml-1, respectively. T-test for dependent samples showed the significant (p < 0.001) differences in counts observed by the two different methods from the same site of the studied environment. Based on method precision, effectiveness of visualization, time consumption and detection capacity, we suggest that the use of SYBR Green I in parallel with image analysis makes the application of epifluorescence microscopy more accurate and less time consuming for overall estimation of phages abundance in the eutrophicated aquatic environments.

Keywords: virioplankton, transmission electron microscopy, epifluorescence microscopy, Curonian Lagoon.