Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 8

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  succession process
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Carabid beetle mean individual biomass (MIB) was analysed in three postindustrial areas, where different environment regeneration types were observed. In total three postindustrial dumps were selected, two of them with spontaneous succession (age about 70 and 15–20 years) and one recultivated (age about 15–20 years). Moreover undisturbed forest was chosen as reference area. Additionally in research areas observations concerning changes in the abundance and dominance of individuals characteristic for open and forest habitats were done. During the field studies 1871 carabids were caught and indicated to species level. The results showed significant differences in MIB values according to regeneration type and succession age. Generally according to one-way Anova analysis MIB values increased with stand age, but there are also difference according to spontaneously revegetaed and recultivated areas. Comparing postindustrial areas with the same age, but with different type of regeneration (spontaneous or recultivation), the MIB values was lower in recultivated area. In these areas, the lowest number of carabids forest species was observed too, which may indicate a strongly disturbed and slow rate of assemblages regeneration. Our results indicate that the mean individual biomass index (MIB) can be usefull tool for assessment succession rate in strongly disturbed postindustrial areas.
Our research was conducted on abandoned fields which had been undergoing spontaneous succession for 40–50 years and then were partly burnt. The main objective of the study was to examine if spontaneous fire in the early successional stage of pine forest causes a decrease in the number of species, diversity and density of seed banks, and an increase in the share of species forming long term persistent seed banks. Standing vegetation and soil seed banks were studied on 20 permanent plots on adjacent burnt and unburnt sites one and twelve years after spontaneous fire. One year after the fire the number of species in the seed banks of both areas was similar (11 and 12 species). In the burnt area the Shannon index and the floristical similarity between the seed bank and standing vegetation were lower, and seed density five times higher than in the unburnt area (15 691.5 m–2 vs.3426.5 m–2). This was mainly the effect of the high number of seedlings of Calluna vulgaris (L.) Hull and Spergula morisonii Boreau germinating from the burnt plots. Twelve years after the fire the number of species in both seed banks had increased little, but seed density in the burnt area (1742.5 m–2) had decreased 16 times, while that of the unburnt area had changed only slightly (2875.5 m–2). At the same time the Shannon index for the burnt area increased considerably, whereas for the unburnt one it did not change. Our study shows that the long-term persistent soil seed bank plays a fundamental role at the beginning of the post-fire regeneration of temperate coniferous forest vegetation. Germination of Calluna seedlings from the burnt soil seed banks in several times higher numbers than from unburnt soil seed banks may suggest that heat from the fire promotes a loss of dormancy in the heather seeds.
The aim of this study was to examine the impact of spontaneous succession in comparison with black fallow on selected physical properties of soil damaged by mining in the area of internal dumping ground Pątnów near Konin. To evaluate the soil physical status, basic physical and chemical parameters (total organic carbon, bulk and particle density, pH), water characteristic curves, and water and air permeability were measured. The observed water retention data with the saturated hydraulic conductivity value were fitted to obtain soil water characteristic curves, differential porosity plots, and hydraulic conductivity function in the vadose zone. Over 30 years of spontaneous succession treatment of the post-mining grounds enriched the resulting Technosol in organic carbon 4 times more than the black fallow treatment. Vegetation caused a high belowground input of organic material, which was apparent by very low bulk density and very high porosity values. Spontaneous succession changed the typical differential porosity of a sandy soil mostly in the mesopore region. Soils under both treatments were characterised by excessive field air capacity, but the soil under spontaneous vegetation revealed higher volume of water available for plants in comparison to the black fallow soil, despite its coarser texture. The black fallow soil had lower and more variable air and water permeabilities than the soil under spontaneous succession. Vegetation including plants with extensive root systems positively influenced soil physical state, thereby improving soil ecosystem stability.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.