| Abstract [eng] |
The topic of the Master’s thesis: Alien Plants in the Environment of Talkša Lake. The aim of the research is to assess the impact of the proliferation and abundance of alien plant species on the natural and recreational environment of Lake Talkša. The object of the research is the proliferation of alien and invasive plant species in the natural and recreational environment of Lake Talkša and the assessment of their morphological indicators. Theoretical (analysis), empirical (observation) and quantitative methods have been applied in the research. The research of flora was conducted between May and October 2018, in the environment of Lake Talkša in the central part of Šiauliai city. In the research of plants the method of field (with the sides measuring 1 × 1 m) description was applied. The variety and dominance of plant species (in %, from 0.1% to 100%) has been assessed visually and scored according to the phytocenological abundance/dominance scale by Josias Braun-Blanquet. The maturity stage groups of the angiospermae explored have been determined based on the features of the above-ground organs. The research data has been grouped and processed by using MS Excel electronic spreadsheet. During the research, 11 species of alien plants were found in the environment of Lake Talkša: 7 in the natural area (2 of which - Canadian goldenrod and Sosnowsky’s hogweed - regarded legally as invasive; 1 - Japanese knotweed, regarded as ecologically hazardous species), 5 in the recreational area (3 of which are regarded legally as invasive species: false acacia, Sosnowsky’s hogweed, ashleaf maple, 1 - sea-buckthorn, regarded as ecologically hazardous species). The morphometric measurements of the explored populations showed that, according to the occupied area, the population of the Japanese reinutre occupying the area of 85 m² was the most abundant, while Sosnowsky’s hogweed occupied 48 m². In the case of an abundant projection coverage of the above-mentioned plant species, the projection coverage of adjacent species of herbaceous plants is significantly reduced. The neglect and abandonment of the natural area is the main cause of the spread of dominating alien plant species. In the recreational area, due to the maintenance of the environment, the impact of the detected alien plant species is minimal. The recommendations of the management plan on the measures required for limiting the spread of alien plant populations and optimising the present condition in the explored areas are provided. It is recommended to use mechanical, chemical and combined measures of eradication. Consistent implementation of site-specific and combined measures to control and eradicate the abundance of alien populations makes it possible to eradicate or at least to prevent the populations from having a negative impact on the native species and habitats, the environment, and the landscape. |
