Semi-natural grasslands are among the most threatened habitats in Europe, endangered mainly by cessation of former management practices and conversion into other types of land use. Extensive research has been carried out in European grasslands in last decades, to explain origins of diversity and to provide guidelines for its conservation. However, the very slow response of perennial plants to landscape changes often impedes to accurately evaluate why species occur just where they occur and not elsewhere. Abandoned fields are perceived as potential habitats for species from declining grasslands. Indeed, many species are able to spontaneously colonise abandoned fields, but many other species are absent from communities that develop there. An important question remains what limits their successful establishment. By answering this question, we can gain also important insights into factors determining species distribution in grasslands because colonization of recently abandoned fields by grassland species is the ongoing process which is not obscured by historical changes in landscape structure. The very basic aim of this thesis was to evaluate the status quo of dry grassland plants in fields abandoned in last two decades. And in the second step, to identify what are the main constrains of successful...

Past extensive changes in land use have resulted in fragmentation of species habitats. Changes in landscape structure have provoked discussion about the prospects of species of fragmented habitats in the future agricultural landscape. Landscape dynamics of plant species is basically a result of extinction and colonization rates. Many studies have confirmed the former expectation that a number of habitats suitable for a plant species in a landscape stay unoccupied. The differences in species distribution and proportion of suitable habitats occupied by a given species are hypothesized to be due to the area and isolation of suitable habitats and colonization and survival ability of a given species. To understand species dynamics in a changing landscape, first we have to reveal the relationships between the distribution of species and their proportion of occupied habitats, habitat age, habitat configuration and species colonization and survival ability. After the complete understanding of the determinants of species dynamics we will be able to predict reliably species prospect in the future. The very basic aim of this thesis was to reveal the determinants of landscape dynamics of dry grassland species in terms of their distribution and frequency in the landscape. The importance of correct identification...

In this thesis, I examine the variation in plant species richness along gradients of productivity and disturbance in grasslands and forest habitats in southern Sweden, and I compare the documented patterns with theoretical predictions. Moreover, I evaluate the relative importance of habitat quality and habitat configuration for the occurrence of field layer species in deciduous forests. Finally, I present a new method for the determination of the regional species pool. To examine regional and local variation in plant species richness, I gathered data on species composition in plots of different size (0.001 - 1000 m2) in three vegetation types (deciduous forests, dry grasslands and coastal meadows) in four regions of southern Sweden (Öland, Gotland, Småland and Uppland). As predicted by the species pool hypothesis, differences in small-scale species richness of deciduous forests and dry grasslands were correlated with differences in the size of the regional species pool. Moreover, among plots large-scale diversity was predictive of small-scale diversity. Species diversity showed a hump-shaped relationship with productivity in forests, and was related to environmental heterogeneity and the size of the 'habitat-specific' species pool. In the two types of grassland examined, grazed sites were richer in species than abandoned sites. Moreover, both species composition and the representation of plants with different life-history characteristics differed between grazed and abandoned sites. As predicted by the intermediate disturbance hypothesis, species richness was highest at intermediate levels of grazing in coastal meadows. However, all the above patterns were scale-dependent, and not observed at all plot sizes. The occurrence of field layer species in deciduous forests was more strongly related to habitat quality (mainly soil factors) than to habitat configuration (forest area and isolation). Across species, low seed production, clonal reproduction and habitat specificity were negatively associated with isolation.

Animals affect vegetation in many different ways. In this thesis we have focused on the impact of wild ungulates in the Czech Republic (wild boar, red deer, sika deer, roe deer). These animals affect vegetation with grazing, defoliation, defecation, browsing and other activities. We decided to study the effect of browsing. The animal trails are formed by browsing animals. These trails can be easily recognized due to long-term browsing. They are especially caused by trampling, which affects vegetation in many ways. The aim of this study is to determine how the vegetation of dry-grasslands (Festuco-Brometea) responds to long-term trampling caused by wild ungulates. We found that on trails, there is more bare soil, less litter and lower vegetation. In its close proximity, there is also a slightly greater diversity of plants than in control samples. Species like Plantago media which are growing straight on the trail, have adapted to trampling, while smaller shrubs (eg. Rubus, Crataegus), start to appear 2 meters from the trail. Using Ellenberg values, we found out that heliophile species, which grow on the trails and the species in control samples need more moisture and more nitrogen. Using the experiment with transplanted blocks, we learned how vegetation responds to the introduction/exclusion of...

Wild ungulates are considered one of the major drivers for shaping terrestrial ecosystems, which has been developing since the early Cenozoic. Understanding the effects of ungfulates on vegetation is necessary for qualified knowledge how European landscape looked prior to human habitation and how it would look like without human intervention. Further, such understanding is of practical importance as management information necessary for managing abandoned landscapes. While the present-day wild ungulate European fauna does not contain several large grazers like auroch (Bos primigenius) anymore, the landscape has long been affected by them. It thus possesses historical experience of response to large grazers, which has been further maintained by livestock grazing. Importantly, the European landscape is experiencing a steady increase of populations of deer (Cervidae) and wild boar (Sus scrofa) with major effects of vegetation and landscape structure. While the effects of these present-day dominants have been studied mainly in forest habitats, there is a growing evidence that they both promote species diversity of forest understory and, interestingly, preferably feed in open vegetation and thus can affect broader landscape heterogeneity. The main aim of this thesis is therefore to examine effects of...

The study was focused on disturbances by wild boar (Sus scrofa) and their impact on vegetation of semi-dry grasslands (Festuco-Brometea) dominated by Brachypodium pinnatum. The research was conducted in military area Hradiště in hilly region of the Doupovské hory. Wild boar rooting activities is main source of disturbances regime in this abandoned, previously agricultural area. The vegetation of artificial small scale soil disturbances was compared to undisturbed control plots and vegetation of natural disturbances by wild boar. Experimental plots were established during the summer 2007. Consequently a vegetation survey of these plots was carried out and soil was mechanically disturbed. Succession on disturbances was annually monitored. The surrounding natural disturbances were also mapped three times a year as a potential source of diaspores and to assess their frequency and effect on the landscape level. The list of species in the 2m, 4m and 16m distance from the experimental plot was also made. Results: Disturbances by wild boar increased species diversity and spatial heterogeneity of semi-dry grasslands. There were some species found on experimental plot, which were present not in the surrounding matrix. Most of them belong to hemicryptophytes and species with long-term persistent diaspores. Presence of...