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The aim of the study was to evaluate the role of different types of linear structures in the preservation of four xerothermic species (Centaurea scabiosa, Euphorbia cyparissias, Melampyrum arvense, and Salvia verticillata) and two weeds (Euphorbia exigua and Thymelaea passerina). Observations were conducted in the agricultural landscape of Western Volhynia with fields of different land use intensity (a large-scale farming system and small traditional arable fields). The total length of the studied structures was 4760 m and the following five categories of structures were distinguished: field road verges adjacent to large (1) and small fields (2), field margins between the patches of xerothermic grasslands as well as large (3) or small fields (4) and balks (5). The distribution and abundance of species mentioned above were recorded there. The survey showed that linear habitats are not suitable for all the studied species; margins between arable fields and grasslands were the most important habitats for both grassland and weed species. Factors responsible for their abundance and distribution along these margins included the following: type of farming system, exposure of the margin, and soil moisture. Grassland species occupied habitats adjacent to small traditional fields with other than southern exposure; weeds were more abundant in drier microhabitas.
The aim of my study was to determine changes in the seed bank and vegetation during the process of overgro-wing of the xerothermic grassland situated on the slopes of the White Mountain (349 m a. s. l., the Central Roztocze Region, South-Eastern Poland). I also examined whether the changes of vegetation can be predicted if we know the structure of the burned seed flora. To achieve this goal I used two sets of data: one collected from three different environments (grassland, brushwood and woodland) at the same time (toposequence), and the other collected twice from the same place at the interval of seven years (chronosequence). I stated that the appearance of even a small number of ornitochorous seeds and their seedlings can be treated as a signal that the bush encroachment will accelerate. Seed number seems to decrease during succession in the analysed sequence of plant communities. The total number of species in the seed bank did not change in the most dynamic plant communities: grassland and brushwood, and it was significantly higher there than in the seed bank of woodland. During the time of observation, the most important quantitative and qualitative changes took place in grassland vegetation, which is more similar to brushwood vegetation now than it was at the beginning of the study.
The study analyses the quantity and spatial structure of the seed bank of the xerothermic grassland located in the Biała Góra near Tomaszów Lubelski (Central Roztocze Region). The seed stock of the bank was compared with the vegetation found in two different patches of the examined grassland. The number of seeds per square meter was estimated at 5328 and 5355, depending on the patch. The seed bank's spatial organisation is clustered. The most important factors determining this spatial distribution are: remaining of the seeds in close vicinity of parent plants, and the "group" dispersal of the seeds and fruits.
The aim of the study was to check which of the xerothermic grassland species create persistent seed bank and what type of germination characteristics they exhibit. The following features of diaspores and the seed bank were taken into consideration: 1) relation between the annual seed production and the seed bank; 2) keeping the germination ability longer than one year, despite the soil samples being kept in the conditions promoting germination; 3) presence in the deeper layers of soil; 4) permanent abundance in soil, also between seed germination and seed shedding time. Carex flacca Schreb., C. transsilvanica Schur, Linum flavum L., Origanum vulgare L. and Scabiosa ochroleuca L. create persistent seed bank, Senecio macrophyllus M. Bieb., Aster amellus L. and Brachypodium pinnatum (L.) Beauv. have the transient type of the bank. Germination time for the grassland species is spring and additionally, in a few cases, early autumn when the most favourable temperature and moisture conditions prevail in the studied plant community. Taking into consideration the changes in the percentage of germinating seeds during the year we can distinguish three types of annual dormancy cycle: Linum flavum pattern – germination occurs exclusively in spring; Salvia verticillata L. pattern – the germination peak in spring; yet, the seedlings are detected during the rest of the season; Senecio macrophyllus pattern – the species with two germination peaks: one in spring, the other in autumn.
The droppings of the Grey Partridge Perdix perdix L. wintering on a set-aside field were found to contain 99.3% of Amaranthus retroflexus and 0.7% of Chenopodium album seed coat fragments. A bird consumed on average 3008 (± 95% CL = 2699–3317) weed seeds per 1 g of droppings. The excreted seed coat remnants made up c. 21% of the swallowed seed mass. Approximately 0.3% of the ingested seeds passed undamaged through the gut. The number of undamaged seeds in the droppings was not significantly correlated with the weight of droppings and the amount of the excreted sand grains, seed coat fragments and other plant parts. After over 1.5 years of storage, 3 out of 18 sown undamaged seeds of A. retroflexus germinated. The average germination time of the excreted seeds was 10 days, while for the fresh ones it amounted to 8.5 days. Our results shows that the Gray Partridge is poor seed disperser and it play important role as predator of A. retroflexus seeds.
The study aimed to evaluate the role of the Rook Corvus frugilegus in the long-distance seed dispersal in agricultural landscape. According to the literature, Rooks feed in the distance 0.3–1 km from the breeding colonies and 10–40 km from winter communal roosts, and these can be also the potential seed dispersal distances. We concentrated on the dispersal of diaspores of ornitochorous species and weeds (called non-ornitochorous) taken probably incidentally during foraging for other edible plant material. The contents of 528 pellets was analysed, 304 were collected at six sites of breeding colonies located in five rural parks and in one park on the city outskirts, and 224 under three winter roosts in the cities. Seeds representing 45 taxa were found, the most important groups among them are: ornitochorous species (10 taxa), non-ornitochorous (27 taxa, mainly weeds and ruderal species) and cereals (4 species). The mean number of seeds varied between 221 and 442 seeds per 100 pellets in the case of breeding colonies, and between 102 and 347 for wintering roosts. Fruits of ornitochorous species are an important element of the diet of the Rook: Cerasus avium and Fragaria sp. during breeding season and Vitis sp., Sorbus aucuparia and Sambucus nigra during winter. Nonornitochorous species are present in pellets in lower numbers and frequencies than ornitochorous ones and they can be divided into two groups: those transported during breeding season (mainly Stellaria media) and those during winter (Setaria sp. and Echinochloa crus-galli). We estimated that the number of non-ornitochorous seeds transported by birds from the biggest observed winter roosts can exceed 400 thousands seeds per month. The value is much lower in the case of the biggest breeding colony: approximately 16 thousands of propagules. We also checked if species found in pellets can germinate in natural conditions under the studied colonies. Viable individuals of 15 nonornitochorous and of one ornitochorous species were found there, and it was observed that disturbances of soil surface promote germination of some analysed species.
The study aimed to describe the seed pool accumulated in the nest material of Magpie Pica pica, and to determine the importance of this mechanism of seed dispersal for such ecological processes as colonization of new habitats and expansion of alien plants. The seedling germination and seed extraction methods were used to determine seed abundance in the soil layer, the inner layer, and in the lining of 9 nests collected in three types of agricultural landscape: the first with domination of arable fields; the second with similar shares of arable fields and other landscape elements such as meadows of different types, shrubs, tree clumps and rushes; and the third with domination of lowland hay meadows. In all the nests, considerable numbers of diaspores were found (from 26 to 371 seeds per nest, belonging to more than 80 taxa). The main plant groups found in the nests are species connected with field roads, weeds and ruderal species, but also meadow and brushwood species were found there. The soil was gathered by birds from habitats with low vegetation cover and large areas of bare soil. Although the structure of seed pool of nests suggests that soil was mainly collected in the close vicinity of the nests’ future location, this mechanism of seed dispersal can probably be involved in long distance dispersal. Seeds of two rare kenophytes: Erucastrum gallicum (Willd.) O. E. Schulz and Diplotaxis tenuifolia (L.) DC were found in the material of nests localized more than 100 m away from their closest populations. It can be assumed that this mechanism of seed dispersal can play a potential role in the expansion of alien plants and colonisation of new habitats.
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