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1
Content available remote Niche Dynamics and Biodiversity : Many Rodent Species on One Marshy Meadow
EN
The ecological niche of a species is determined by its tolerance to environmental factors and by interactions with other species, particularly those using the same resource. We assessed spatial niches of four rodent species coexisting in one meadow habitat within the Białowieża Primeval Forest. Niche characteristics were based on the valorisation of the habitat around live-trapping sites visited by rodents during seven years of the study. The population size of each species was monitored and expressed as an average annual density. The root vole Microtus oeconomus was the most numerous and dominant species, with its density widely fluctuating due to the temporal increases of predation pressure exerted by the weasel Mustela nivalis. During the study period, the spatial niche of the root vole was nearly constant, with only significantly increased tolerance towards shrub covered sites at times of its high population density. However, even a slight niche expansion of the highly abundant root voles displaced accompanying species: the bank vole Myodes (Clethrionomys) glareolus, the yellow necked mouse Apodemus flavicollis and the striped field mouse A. agrarius, from their preferred sites and efficiently decreased rodent species diversity in the studied habitat. This study illustrates a possible mechanism of the direct effect of predation on the dominant prey species population and indirect one on the species diversity changes over ecological time.
2
Content available Zagrożenie pożarowe Puszczy Białowieskiej
PL
Cel: Celem publikacji jest ocena zagrożenia pożarowego Puszczy Białowieskiej w kontekście rozpadu drzewostanów świerkowych w wyniku gradacji kornika drukarza. Artykuł powstał w dużej mierze na podstawie pracy pt. „Wpływ ilości martwego drewna w Puszczy Białowieskiej na zagrożenie pożarowe oraz zagrożenie dla ludzi” [1] zleconej przez Ministerstwo Środowiska, sfinansowanej ze środków Narodowego Funduszu Ochrony Środowiska i Gospodarki Wodnej. Wprowadzenie: Puszcza Białowieska jest szczególnie cennym pod względem przyrodniczym obszarem, na którym wskutek niespotykanej gradacji kornika drukarza (Ips typographus) w ostatnich latach doszło do rozpadu drzewostanów świerkowych na powierzchni kilku tysięcy hektarów. To zjawisko o charakterze klęskowym spowodowało wzrost obciążenia ogniowego oraz zwiększenie łatwopalnej martwej biomasy, która stwarza duże zagrożenie pożarowe. W tle toczących się sporów i dyskusji pomiędzy różnymi grupami interesariuszy na temat ochrony Puszczy, kluczowe staje się pytanie, czy człowiek powinien czynnie przeciwdziałać i ograniczać degradację cennych siedlisk przyrodniczych, czy nie ingerować w siłę natury i pozostawić je samym sobie. Jednym z istotnych elementów czynnej ochrony Puszczy Białowieskiej jest jej ochrona przeciwpożarowa, dlatego w artykule przedstawiono ocenę istniejącego zagrożenia pożarowego, analizę obecnego systemu zabezpieczenia przeciwpożarowego wraz z propozycją jego poprawy. Metodologia: Oceny zagrożenia pożarowego Puszczy Białowieskiej dokonano w oparciu o analizy: kategoryzacji zagrożenia pożarowego lasu sporządzonych w planach urządzenia lasu nadleśnictw puszczańskich i planie ochrony Białowieskiego Parku Narodowego; występowania pożarów lasu w latach 2000-2015; obecnie funkcjonującego systemu ochrony przeciwpożarowej i jego oceny w świetle obowiązującego prawa oraz wpływu ilości i rodzaju wydzielonej biomasy na zagrożenie pożarowe. Wnioski: Zagrożenie pożarowe Puszczy Białowieskiej wzrosło w wyniku rozpadu drzewostanów świerkowych i związanych z nim zwiększeniem obciążenia ogniowego oraz pojawieniem się pokrywy trawiastej, która uschnięta sprzyja powstawaniu i rozprzestrzenianiu się ognia. W związku z zaniechaniem działań prewencyjnych i odstąpieniem od zasad gospodarki leśnej, które spowodowały wzrost ryzyka pożarowego, konieczne jest dostosowanie istniejącego systemu ochrony przeciwpożarowej Puszczy Białowieskiej do występującego ryzyka.
EN
Aim: The aim of this paper is to reveal evaluation findings in respect of forest fire risk at Białowieża Primeval Forest, in the context of spruce trees degradation caused by a bark beetle invasion. The article is based on the report “Level of forest fire risk and threat to humans in relation to the volume of dead wood in Białowieża Forest” [1], which was commissioned by the Ministry of Environment and financed by the National Fund for Environmental Protection and Water Management. Introduction: Białowieża Primeval Forest is of particular importance in relation to environmental values. However, in recent years, spruce tree stock has been exposed to progressive degradation across an area exceeding thousands of hectares, caused by an unusually large infestation of bark beetle (Ips typographus L.). Such developments, accompanied by symptoms associated with natural disasters, have increased the presence of combustible materials creating a potential fire hazard. Current debate and controversy amongst diverse interest groups revolves around the question of whether active human intervention should constrain the degree of degradation in the precious environment or avoid interference and allow nature to pursue its own course. One essential element of proactive defence at Białowieża Forest is an endeavour to protect it from the risk of fire. For this reason the article contains an evaluation of existing fire hazards, an analysis of current protection systems in place and proposals for the improvement of such systems. Methodology: An evaluation of fire risk in Białowieża Primeval Forest was made by reference to the following: Forest fire risk categorization for Białowieża forest area management plan and conservation plan of Białowieża National Park; frequency of forest fires during the years 2000-2015; current forest fire protection system in force and evaluation of the system in context of current legal requirements, taking account of influences on the risk of fire caused by a volumetric increase and type of biomass generated through degradation. Conclusions: The risk associated with Forest fires has increased as a result of spruce trees degradation in Białowieża Primeval Forest. In addition to this increase of combustible material other factors, which contribute, include the emergence of grass overlays across dead wood areas. Such grass, when dry, leads to outbreaks and propagation of fires in forest areas. Abandonment of prevention activities and departure from forest management principles compel the adaptation and adjustment of existing fire protection systems in accordance with emerging threats.
EN
Thermophilous oak wood is the most species-rich forest habitat in the zone of mixed deciduous forests. A very limited amount of it has been saved in good condition. We investigated the principal hypothesis that the vegetation and seed banks, especially of the ancient forest species, are good indicators of habitat naturalness and its aptitude for restoration. Vegetation and seed bank sampling were carried out in fragments of forest with a known management and disturbance history over the past 80 years. We predicted that natural and anthropogenic transformations of tree stands would be significant factors shaping species composition and similarity of vegetation and seed banks. The closest similarity was observed between the seed banks of plots which were never logged. The least related to others was the seed bank of the logged site, whose soil was ploughed prior to tree replantation. The highest number of ancient forest species was recorded in the vegetation (33 species) and in the soil seed bank (21 species) of the least transformed patch of thermophilous oak forest. It was decreasing gradually with increase of the tree canopy cover on the research plots. Our results indicate also that the higher the coefficient of similarity between seed bank and vegetation, especially of the ancient forest species, the higher the forest’s naturalness. We conclude that restoration of thermophilous oak wood has the highest chances for success in patches with well preserved seed banks and vegetation.
4
Content available remote Small scale spatial pattern of a soil seed bank in an old-growth deciduous forest
EN
We studied an old growth deciduous forest seed bank to examine how its potential role in regeneration is shaped by natural forest environment. Our research questions were: is the spatial pattern of seed bank influenced by local variation in elevation, soil moisture and light intensity, and what is the impact of herb layer characteristics on seed bank pattern. We recorded species composition of the herb layer and seed bank on a 2 x 40 m study plot divided into 20 quadrates, situated in a natural oak-hornbeam forest, in the Białowieża Primeval Forest, (NE Poland). Soil cores were sampled from two soil layers (0-5 cm and 5-10 cm) yielding altogether 40 samples of a total 15.9 dm[^3] and 0.159 m[^2]. Seeds were extracted from soil samples under a microscope. Ellenberg indicator values were used to characterize light (L) and moisture (F) conditions. Relative quadrate elevation was averaged for nine points. There were 6.65 x 10[^3] seeds m[^-2] in upper soil layer and 3.00 x 10[^3] seeds m[^-2] in lower soil layer. Seed bank structure constituted of patches 6 m diameter in the upper soil layer and 4 m in the lower soil layer. Aggregated pattern of the seed bank was influenced by clumped distribution of plants in the herb layer. Seed bank species richness in the upper soil layer was correlated with moisture (r = 0.485, P =0.03) and light (r = 0.526, P = 0.0172) values. Seed densities were correlated with moisture (r = 0.848 P <0.0001 upper and r = 0.491 P = 0.0278 lower soil layer) and light (r = 0.803 P <0.0001 upper and r = 0.751 P = 0.0001 lower soil layer). Seed density in upper soil layer was negatively correlated with elevation (r =.0.485 P = 0.0422). Higher seed density and species richness of the seed bank associated with better light conditions and higher moisture is probably caused by higher seed production in favourable conditions, and factors promoting seed persistence in soil. Our results indicate, that even subtle changes in light, moisture and mean relative elevation can shape seed bank spatial pattern on a fine local scale, differentiating the response of this community to small scale disturbances present in natural forests.
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