| Abstract [eng] |
The work presents exploration and evaluation of the data on the vegetation which forms on beaver lodges and in abandoned beaver meadows and its alteration in time. Likewise, comparison of the abandoned beaver meadows phytocenoses with the plant communities of naturally flooded meadows is presented. Research on meadows phytocenoses occured in 2007 – 2008, each year explorations were holding from July till August, in Sąvalka stream valleys (East Lithuania). Three abandoned beaver meadows and three naturally flooded meadows were explored. Botanical composition of plants communities was determined using Braun-Blanquet method (Braun-Blanquet, 1964), took 48 squares, each 4 m2, in six meadows and 21 squares on beaver lodges, each 10 m2 , and evaluating all plant species from them. The scale of H. Ellenberg (2001) was used to decide plants species attachment to hydrological regime, soil reaction, and trophical features of abodes. Coefficients of Sörensen and Jaccard (Dombois-Mueller, Ellenberg, 1974) were used to express floristical similarity of communities. In abandoned beaver meadows 109 plant species were identified meanwhile in naturally flooded meadows – 100; 104 plant species were identified on beaver lodges. Various phytocenoses are formed in beaver meadows, however, communities belonging to the Cl. Molinio-Arrhenatheretea elatioris R. Tx. 1937 are the most frequent. In comparison with naturally flooded meadows, phytocenoses of beaver meadows are distinguished by the following peculiarities: there are plenty of plant species tolerant to higher soil dampness and acidity, there was found small amount of oligotrophic species, however mesophytes have dominated in all places of investigation. Plant communities of beaver meadows have features characteristic of the early succession stages, and their features can be explained by specific habitat conditions, the most important of which seem to be the increased soil dampness and acidity. Also the investigation show that there are certain species of plants that settle down beaver lodges. Those species have wide ecological plasticity and approve well aerated and damp soil. |
