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The dynamics of plant communities is an important issue for sustainable forest management. In case of several parallel dynamic tendencies occurring within a group of research objects similar to each other, their demarcation may be difficult. The aim of the research was to check the applicability of numerical classification to distinguish the dynamic trends of plant communities on the example of multidirectional reaction of oligotrophic pine forest Peucedano−Pinetum W. Mat. (1962) 1973 to surface fire. The research was conducted in the post−fire site originated in spring 2015 in the Kampinoski National Park (central Poland). The set of 45 permanent plots was established. They differed in the degree of disturbance, measured as the share of the total burnout of the soil organic horizon. The phytosociological survey was carried out every year between 2015 and 2018, using the Londo scale. The use of cluster analysis for classification of vegetation changes requires an uniform unit for each of the variables. It was expressed as the ratio of the difference between the positions of the research plots (registered vegetation states) in the indirect space of the ordination analysis and the time elapsed between them. Thus the subject of the classification were the multidimensional changes (beta diversity) expressed in the unit of speed. The obtained material was arithmetically transformed and ordered using the PCoA method with the Bray−Curtis distance. The range of changes was calculated as differences in the plot position in three annual intervals separately for each of the four main gradients of the ordination. The 12 annual change values obtained for each of the plot were subjected to Ward classification. In order to verify the nature of the obtained clusters, collective covers of species belonging to higher syntaxones were calculated and their changes during the research period compared using the Kruskal−Wallis and Mann−Whitney tests. The significance of differences in the degree of initial disturbance was also checked. On the basis of the Ward classification, the division into five dynamic groups of plots was obtained. An analysis of the changes in the coverage of higher syntaxonomic groups revealed the existence of statistically significant differences between the clusters in 55 out of 110 possible cases. The presence of significant differences in the initial degree of disturbance by fire was also noted. The studied plot groups represent the regeneration process (A and B), pine forest regression combined with secondary succession (groups C and D) and the control group – not−disturbed pine forest (E). The cluster analysis method was proved to be an effective tool for classifying objects in terms of different tendencies of vegetation dynamic.
Paper presents some geobotanical and soil research, which are carried out in pine forest, situated in the five geographical regions of Poland (Wielkopolska, Bory Tucholskie, Puszcza Biała, Puszcza Białowieska and Roztocze). The aim of the study was to make a phytosociological diagnosis, estimation of soil condition and analysis of phytocenoses for zoocenological purposes. Studied plant communities arc represented by two regional association: Leucobryo-Pinetum and Peucedano-Pinetum and two types of soil: podzolic and rusty soil belonging to the podzolic earthe. Physical and chemical soil properties, phytosociological data, as well as results of floristic composition of different regeneration stage of pine forest are presented.
Cladonio−Pinetum Juraszek 1927 forest is protected in Europe as the Natura 2000 habitat. Nowadays its naturalness is often considered to be doubtful. In spite of the many research, the knowledge about ecology and dynamics of this community is still insufficient. The aim of the research is to define the stability of the community within ‘Bory Tucholskie' National Park. The site is located in the area of the best developed patches of the habitat, in north−western Poland. Two datasets of relevés were used. The first comes from published data and includes 123 relevés made in year 2000. The other comes from own fieldworks performed in 2014. Due to the high homogeneity of geology and soils of the study site, repeated chronosequence method could be used to compare both datasets. The information about herb and moss layers of all relevés was compared using DCA method. The change in community was measured as a shift in the position within the main gradient of DCA over 14−year period. It was calculated for 122 pairs of relevés. Than the model of the speed of community change was computed for the main gradient. We used two methods of calculation of duration of the lichen−rich pine forests. The first was based on the calculated ranges of distinguished associations and the other used the model of cover of species connected to Cladonio−Pinetum forest. As the speed of community change in the gradient and the distance between distinguished communities were known, the time of community duration could be computed. According to obtained results, Cladonia−Scots pine forest (Cladonio−Pinetum) and lichen rich fresh pine forest (Leucobryo−Pinetum with Cladonia) of ‘Bory Tucholskie' National Park will last for 64−109 years. This result shows, that the considered Natura 2000 habitat is unstable. It is the possible development stage within managed forest stands and active conservation is necessary where its preservation is needed.
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