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The aim of the paper is to define a relationship between the diversity in structural features of the Carex digitata population and the dynamics of natural and disturbed anthropogenically oak-hornbeam communities in the cycle of 29-year research (1987-2015) conducted on permanent plots in the Knyszyńska Forest. The results of the research indicate that the population dynamics corresponds significantly to the community dynamics, whereas the existing interrelations are a response of Carex digitata population to dynamic vegetation changes undergoing in natural habitats (fluctuation) and under the influence of anthropogenic disturbances (degeneration as a result of pinetization followed by regeneration). This is reflected in a different spatial organization, age structure, size diversity of individual plants, as well as in various mechanisms regulating the number of individual plants in a population. Models of population dynamics in the light of dynamics of the natural and disturbed forest communities can be explained from the viewpoint of equilibrium and non-equilibrium in the nature. It has been proved that in stable communities, where variations in vegetation have a character of little fluctuations and indicate a state of a relevant equilibrium in the nature, the population of Carex digitata also reaches a phase of relevant equilibrium. In such a phase the size of the sedge population is small and changes in the number of individuals in the 29-year cycle slightly fluctuate. A different variation in the population features has been reported in the anthropogenically disturbed community. Processes of degeneration and regeneration are accompanied by rapid dynamic vegetation changes (a state of non-equilibrium) and rapid changes in structural features of the Carex digitata population. The sedge reaction to the dynamic variations in the communities can be explained by a different life strategy which differentiates morphological and developmental features of individuals and thus determines variation of properties of the population.
The aim of the paper was to define a relationship between the structure and dynamics of the Carex digitata population. Additionally, modifications in the development of an individual and its life strategy in disturbed communities were analysed. The species was studied in the natural and anthropogenically disturbed oak-hornbeam communities over 23-years of research (1987-2009) conducted on permanent plots in the Knyszyńska Forest. The results of the research indicate that in the natural community, C. digitata individuals reach the phase of flowering and fruition in the 4th year of the life cycle, while in the disturbed community dominated by pine trees - in the 2nd year of the life cycle. Modification of the C. digitata life cycle can be attributed to different reactions of individuals to disturbances in the community, microclimatic, phenological and biocenotic balance to which C. digitata is exposed as a results of the degeneration (pinetization) of the community. The sedge responds differently to specific ecological conditions in the natural and anthropogenically disturbed oak-hornbeam communities due to different life strategies, which affect morphological and developmental features of individual plants, and thus induces changes in the structure and dynamics of populations. This is reflected in a different spatial organization, age structure, size diversity of the individual plants, as well as in various mechanisms regulating the number of individual plants in a population.
The study was performed to identify, delimit and evaluate the current status of Arctostaphylo-Callunetum R.Tx. et Prsg 1940 heaths, as well as to point out possible threats to these communities and means of their protection. The heaths are in Czerwony Bór (PLH 200018) in Podlaskie voivodeship, NE Poland, in the area included in the Natura 2000 network. The study was performed in 2008 with the use of GPS method over the study area of 3,784.04 ha. The area of Czerwony Bór includes 8 stands with dry heaths of Arctostaphylo-Callunetum of the total area of 21.7 ha. They are represented by typically developed and well-preserved patches of vegetation (90%) of the area of 19.5 ha and not so well preserved patches (10%) occupying the area of 2.2 ha. In general, their natural value in the area of study is high and the representative character, degree of preservation of the structure and functions are excellent. The main threat to the dry heaths Arctostaphylo-Callunetum in the area of Czerwony Bór comes from the forest management procedures aimed at reclamation of the area left after the army training grounds, reforestation in the form of large-area single-species forest plantations, forestation of the land that has not been forested earlier. In the areas where no plantation have been started the process of secondary succession is observed. As a result of this process heaths are replaced by forest-thicket formations. The active protection of the heaths in the area studied should include prevention of secondary succession, mowing and removal of forest-thicket formations and changes in forest management policy towards maintenance of open space by periodical removal of vegetation to bare soil.
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