Central Europe wet meadows are characterized by considerable species richness. The biodiversity maintenance of the wet meadows is connected with regular management (i.e. grazing or mowing). As their area drastically decreased due to changes in land use in the last century, they have become the object of interest among scientists, conservation biologists. This thesis is composed of three original studies which are focused on escribing diversity patterns of the whole spectra of wet meadows at landscape level and dynamic of their changes depending on different management regimes (mowing/abandonment,fertilizing/unfertilizing). The synthesis of these studies reveals the description of the processes underlying the wet meadows species loss depending on land use changes and proposes the principles for sustainable conservation management.

Understanding the importance and the possible use of clover in permanent grassland is very important. Their irreplaceable role in nitrogen fixation and enrich the soil of this essential element is very important. The significance of herbs in grassland is also significant, even though its importance is often overlooked. Herbs not only serve as indicators of habitat conditions, but also can improve the quality and palatability of forage. If we know the herbs and legumes and their habitat requirements will help us select the most suitable way of management and the effective use of the potential of the habitat. The aim of the thesis was to observe conditions of use and the occurrence of selected legumes and herbs in TTP. Research can therefore conclude that the biggest influence on the composition of the grassland have ecological conditions. Way management can to some extent affect the crop themselves, but the biggest factor remains what we can not influence and that is the weather. The results also shows that the richer pastures.

The aim of the study was to assess succes of some plant species in restoration of species rich meadows in Bílé Karpaty mountains. The meadows were sown with regional seed mixtures. It also deals with a diversity of the growths old 1 till 8 years and its relation to environmental conditions.

The master?s thesis is part of the project GA ČR č. P504/11/1151- Role of plants in the greenhouse gas budget of a sedge fen. This thesis deals with the decomposition of aboveground vegetation in a herbaceous wetland. The decomposition rate was established on the flooded part of the Wet Meadows near Třeboň. The rate of the decomposition processes was evaluated using the litter-bag method. Mesh bags filled with dry plant matter were located in the vicinity of the automatic meteorological station at four randomly selected sites. Values of the decomposition rate were assessed in two experiments. In the first experiment the litter bags were fixed in April 2009. The litter bags were fixed in the vertical position and they had one size. Values of the decomposition rate were assessed for 6 sampling dates and the total exposure time was 2,5 years. The decrease of the total dry mass was 18,37 % in the first year and 13,05 % in the second year. The value of LDR was 0,7227 in the first year and 0,4740 in the second year. In the 2nd experiment the litter bags were fixed in November 2010. The litter bags were fixed in the vertical and horizontal position, respectively, and they were of two sizes (small, big). Values of the decomposition rate were assessed for 2 sampling dates and the total exposure time was one year. The total annual value of LDR was 0,5212 for the vertical bags and 1,0676 for horizontal bags.

During the breeding season in 2007, the mapping of the nesting ranges in birds of the order Passeriformes was carried out on the chosen localities in Třeboň wet meadows within the Třeboňsko landscape; Aim of study was to order qualitatives and quantitatives status of the Passeriformes within localities and their comparasion. Localities were situated in the immediate vicinity of Třeboň. The total mapped area was 25 hectares. The Vegetation was dominated by tall sedges (locality New station). The principal biotops consisted of tall sedges biotop M1.7 and K1 (locality New station and locality Old station) and V1 biotop. Within Old station locality and Opatovický locality it was especially: T1.5 and T1.4 and X5. Nesting birds were counted by the mapping method (Janda a Řepa, 1989). The GPS system was used for the recording of single males. Twenty three passerine bird species were found within localities. In total, nine bird species were founded in all the localities. The most abundant species were: (Acrocephalus schoenobaenus) the Sedge Warbler, (Luscinia svecica cyanecula) the Bluethroat, (Locustella naevia) the Grasshopper Warbler (Old station locality and New station locality), Opatovický locality was dominated by Acrocephalus schoenobaenus the Sedge Warbler. There was signigicant differences of total density of bird assemblage betwen Opatovický locality and New station locality and Old station locality and Opatovický locality. High breeding density was found especially in the Whinchat and the Bluethroat on New station locality. High conformity of bird assemblage was among New station locality and Old station locality.

The MSc thesis is part of the project of Ministry of Environment of the Czech Republic entitled Czech Terra, which aims at assessing the carbon budget and cycle in the main types of ecosystems in the Czech Republic. This thesis is focussed on the production of aboveground biomass of Carex acuta, which dominates the unmanaged and permanently flooded part of the Wet Meadows. The seasonal dynamics of aboveground plant production was followed using a series of 9 destructive harvests during the vegetation season. On each date, four 0.5x0.5m2 samples were taken from the wetter, and four samples from the drier part of the stand. The maximum value of live biomass of C. acuta (550.8 g.m-2) was recorded on 13.6 2008. The highest value of live biomass of all species reached 602.4 g.m-2. The maximum total biomass (without litter) reached 994.6 g. m-2. The highest value of productivity of C. acuta (12.46 g.m-2.day-1) was recorded on 24. 5.

This study observes an influence of two-year application of NPK fertilizer on the amount of soluble nitrogen, microbial N transformations, and microbial biomass and the composition of microbial community in mineral and organic soils of two wet meadows. This study is the first version of manuscript, supplemented with a wider literature review, which will be submitted in 2010.

This MSc thesis is part of the project GACR 526/09/1545 Importance of newly assimilated carbon for the plant-soil interactions in wet grassland ecosystems in varying environmental conditions, which focuses on the effects of eutrophication on selected wet meadows with mineral or organic soil in the Trebon Biosphere Reserve. The results of this project will serve as a basis for developing a suitable ecosystem management for wet meadows, especially for sites registered as nature reserves. Pot experiments were carried out with Carex acuta, a dominant species of wet meadows that has already been subject of many studies. The aim of this work was to find out how C. acuta responds to different levels of fertilization and soil flooding under controlled conditions. The growth of the generative shoots of C. acuta was significantly affected by fertilization. The growth of vegetative shoots was significantly influenced by the soil organic matter content and fertilizer addition. The vegetative shoots reached greater length than the generative shoots. The pot experiment indicates that fertilization has not a large influence on the growth of C. acuta. This finding may explain field observations that C. acuta is gradually replaced in eutrophic habitats by stronger competitors, especially Phalaris arundinacea.

Seagrasses are considered highly important CO2 sinks, with the capacity to store substantial quantities of organic carbon in the living biomass and sediments, and thereby acting as a buffer against climate change. In this thesis, I have studied carbon storage variability in temperate and tropical seagrass habitats and identified factors influencing this variation. In addition, as seagrass areas are decreasing worldwide, I have assessed effects of different anthropogenic disturbances on carbon sequestration processes. The result from this thesis showed that there was a large variation in carbon storage within and among temperate, tropical and subtropical regions. The highest organic carbon stocks were found in temperate Zostera marina meadows, which also showed a larger carbon storage variability than the subtropical and tropical seagrass habitats. The tropical and subtropical seagrass meadows had inorganic carbon pools exceeding the organic carbon accumulation, which could potentially weakens the carbon sink function. The variability in organic carbon stocks was generally strongly related to the sediment characteristics of the seagrass habitats. In Z. marina meadows, the strength of the carbon sink function was mainly driven by the settings of the local environment, which in turn indicates that depositional areas will likely have higher organic carbon stocks than more exposed meadows, while in the tropics seagrass biomass was also influencing sedimentary carbon levels. Furthermore, locations with large areas of seagrass were associated with higher carbon storage in tropical and subtropical regions, which could be related to increased accumulation of both autochthonous and allochthonous carbon. In an in situ experiment, impacts on carbon sequestration processes from two types of disturbances (with two levels of intensity) were tested by simulating reduced water quality (by shading) and high grazing pressure (through removal of shoot biomass). At high disturbance intensity, reductions in the net community production and seagrass biomass carbon were observed, which negatively affected carbon sequestration and could impact the sedimentary organic carbon stocks over time. In the treatments with simulated grazing, erosion was also seen, likely due to an increase in near-bed hydrodynamics. When experimentally testing effects of increased current flow on organic carbon suspension in Z. marina sediment, a ten-fold release of organic carbon with higher current flow velocities was measured, which resulted in an increase in the proportion of suspended organic carbon by three times in relation to other sediment particles. Therefore, periods with enhanced hydrodynamic activity could result in a removal of organic carbon and thereby likely reduce the seagrass meadows’ capacity to store carbon. The findings of this thesis add to the emerging picture that there is a large natural variability in seagrasses’ capacity to store carbon, and highlight how human-induced disturbances could negatively affect the carbon sink function in seagrass meadows. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

The objectives of the study were to determine the year-round distribution and habitat selection of four marsh passerine species, as described by vegetation type and its physical characteristics, and to investigate interspecific competition as a factor in the habitat selection of the Long-billed Marsh Wren and the Red-winged Blackbird. Fulfillment of these objectives should help the B.C. Fish and Wildlife Branch to assess the effects of their management plans on marsh passerines. I determined the abundance of four passerine species in different vegetation types via marsh census transects over the period of one year. Nesting habitat and breeding information on marsh wrens and redwings was obtained via nest study plots. The results were: Areas traversed from the central and deepest marsh outward towards higher ground are inhabited by redwings, marsh wrens. Common Yellowthroats, and Song Sparrows, respectively. Habitats of wrens and redwings are spatially and temporally segregated. Wrens use the "Dense Spiraea" (Hardhack shrub) habitat extensively, while redwings use it hardly at all in the marsh. Similarly, redwings are abundant in Scirpus cyperinus (Hairy-seeded Bulrush), whereas wrens seldom use this habitat. Both wrens and redwings use other vegetation types, but redwings use them in the late spring, whereas wrens use them in the summer. Both wrens and redwings have lower reproductive success when nesting in close proximity than when nesting apart. This supports the hypothesis that interspecific competition exists and indicates that selection may favour habitat segregation. I also found mutual suppression of reproductive success when the effects of different vegetation types were removed. The results were not statistically significant however, possibly due to small sample sizes. Of the observed differences between the physical nest site parameters of wrens and redwings, vegetation height and presence and/or depth of water require further investigation as factors in the habitat selection of the two species. Bren-wren competition does not appear to affect wren nesting success in the present study marsh. Management recommendations are given based on the objective of maintaining and possibly enhancing bird species diversity in the study marsh. / Science, Faculty of / Zoology, Department of / Graduate