Botanica Lithuanica, Volume 16, Number 4

Atgal

Botanica Lithuanica, Volume 16, Number 4

2010 m.

Studies on ecological distribution of silver (Betula pendula Roth.) and downy (Betula pubescens Ehrh.) birch in mire (natural and drained) habitats were conducted in 45 birch stands (older than 10 years) and in 25 former clearcut habitats (up to 10 years of age) where no silvicultural measures were applied. The distribution of silver and downy birch in birch stands of different age, growing on mire habitats of different types (trophotop) and in various mire zones, was determined; the influence of different factors (stand age, site hydrotope and trophotope, etc.) on their distribution was estimated. The portion of silver birch in the species composition of raised bogs and transition mires decreases with age. In fens silver birch grows only in young, up to 10-year old, stands. In different mire zones, silver birch is distributed rather unevenly. The depth of ground water level, seed source, litter/peat layer depth produce the strongest influence on silver and downy birch distribution in mire habitats. The influence of grasses and litter/peat layer depth on birch species composition is significant only in the initial period of stand regeneration.

The paper presents molecular characterization data of quarantine fungus Diaporthe/Phomopsis vaccinii and related isolates. In 2002 this fungus was for the first time observed in Lithuania on Vaccinium corymbosum, later on V. macrocarpon. The identification of this pathogen is often difficult and lengthy when using only classical methods based on morphological features. Therefore, the molecular diagnosis, based on rDNA region sequencing, of several isolates primary named as Phomopsis vaccinii originating from Lithuania was carried out. Sequences of eight strains (Phomopsis vaccinii VAAT-PZ4, VAAT-PZ5, VAAT-PZ6, and VAAT-PZ11, Diaporthe eres VAAT-4.244 and VAAT-PZ8, Phomopsis sp. VAAT-PZ15 and BI-PH02B) were analysed by comparing with the accessions from GenBank.

This paper presents a study of two Stereocaulon species from Poland – S. saxatile and S. subcoralloides. Both taxa are recorded for the first time for the country. S. subcoralloides is also new to the Carpathians. Lectotypification of S. subcoralloides is proposed basing on the results of U. Laine. Short characteristics of the taxa are given as well as notes on their taxonomy, chemistry, habitat requirements and distribution.

The northern edge of the distribution area of European hornbeam (Carpinus betulus L.) makes the border between northern and southern geographical belts of northeastern sector of Central European province. On the territory of Lithuania Quercus robur forests with Carpinus betulus (ass. Tilio-Carpinetum) are the climate climax vegetation of southern belt, while Quercus robur forests without Carpinus betulus belong to the northern one. Flora composition of these oakwoods was compared. Gradual changes in the flora composition of these communities in the north-eastern direction were noted. In the direction of north-eastern border of Carpinus betulus range (ass. Tilio-Carpinetum) and beyond it in oakwoods of Lithuania and Latvia the number of species characteristic of the Querco-Fagetea class reduces as well as species of temperate and temperate-submeridional distribution, while the number of boreotemperate species increases. The species of the last-mentioned group are indifferent from phytocoenological point of view, majority of them are not constant and they do not form the new complex of diagnostic species.

This study describes the vegetation composition of main plant communities of the Sundic-Baltic sand-dune vegetation complex on dry coastal dunes in the protected areas along the southern Baltic coast. The data comprise 145 relevés of 4 different countries (G, PL, RU and LT) distributed among 15 sites. 11 coastal communities were considered. Pioneer communities were dominated by herbs and had low coverage and diversity. Further successional stages had low coverage but moderately higher diversity, with sedges and grasses dominating. Older stages had a higher total mean coverage, and shrubs as well as trees were more abundant. The dune habitats under investigation are important in conservation of threatened species because of the recorded red-listed vascular species (24), lichens (17) and bryophytes (2). Although the examined coastal habitats contain a highly functional and structurally diverse ecology, this ecology is gradually being degraded by coastal erosion, human impact and nitrogen deposition.

The study provides data on the investigation of vegetation cover in Smeltė Botanical Reserve. This protected area is the smallest state reserve (3.6 ha) established in Lithuania. The main function is to preserve the fragments of rare in Lithuania salt meadows (Cl. Asteretea tripolii Westhoff et Beeftink in Westhoff et al. 1962, Ass. Juncetum gerardii Nordhagen 1923) and red-listed plant species. Due to natural circumstances and anthropogenic activity, the plant communities are located in belts: sown meadows dominate on the upper terrace; on the central terrace – communities of Sedo-Scleranthetea Br.-Bl. 1955 and Aveno-Medicagetum falcatae Br.-Bl. et De Leeuw 1936 are still forming; on the lower terrace – the fragments of Juncetum gerardii Nordhagen 1923 community occur. Small area and inconsiderable diversity of habitats in the protected territory predetermined rather small number of vascular plant species: 163 of them were inventoried in 2007–2008; 4 red-listed plant species (Aster tripolium L., Glaux maritima L., Juncus gerardii Loisel. and Allium scorodoprasum L.) were recorded. More than 3 700 individuals of Aster tripolium, the thickets of Glaux maritima (35 m2) and Juncus gerardii (3 m2) occur. The future of plant communities and red-listed species will depend upon the quality of their maintenance and management according to nature management plan. Smeltė Botanical Reserve can become a unique example of preservation of natural values in intensively urbanized environment.

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