In this thesis, I aimed to identify factors shaping plant distribution at different spatial scales, correlate them with environmental heterogeneity, identify causal processes and test general hypothesis on the nature of response curve shapes and species richness patterns. General review of the topic is introduced in the first chapter, followed by five chapters presenting three already published studies and two manuscripts. The first study deals with processes responsible for creation of fine-scaled spatial pattern of spruce seedlings and saplings, emerging after bark-beetle disturbance in mountain spruce forest. Aggregated pattern, replicating previous generation of spruce trees, emerges in consequence to microsite-dependent mortality, as was surveyed through repeated monitoring of the fate of individual seedlings. The second study explores spatial variability in forest understory temperatures at the landscape scale and its relevance for understory plant distribution. As the main source of variability in understory communities we identified seasonal maximum temperatures. Using GIS modelling approach, we created spatially continuous prediction, which outperformed state-of-art climatic grids used currently by ecologists. The third study on the shape of species responses along elevational gradients...

Chez les procaryotes, les systèmes ABC (ATP-binding cassette) canoniques permettent un import efficace et de haute affinité du nickel, en grande partie via l'action de la Ni-BP (nickel-binding protein) qui va jouer le rôle de récepteur extracytoplasmique du nickel avant son passage à travers la membrane interne. Dans ces travaux, nous avons cherché à mieux caractériser les stratégies d'import de nickel par les bactéries, notamment par l'étude cristallographique des Ni-BP. La résolution des structures de cinq de ces protéines, en interaction avec du nickel, nous a permis d'identifier les sites de fixation et ainsi de mettre en évidence les différents modes d'interaction de ce métal avec les Ni-BP. Nos résultats montrent notamment que la coordination du nickel requiert toujours la présence d'un métallophore exogène, appelé nickelophore. En parallèle, des études in vivo ont été conduites sur Escherichia coli, montrant que cette bactérie semble être capable de synthétiser son propre nickelophore. D'autre part, ces travaux ont permis la résolution de la structure de HypB de Helicobacter pylori en interaction avec du nickel. Celle-ci permet de mieux appréhender le rôle central de cette protéine au sein des voies de maturation des enzymes à nickel. / In prokaryotes, canonical ABC (ATP-binding cassette) importers allow an efficient uptake of nickel with high affinity through the inner membrane, largely via the action of the extracytoplasmic nickel-binding protein (Ni-BP). In this work, we intended to better understand the strategies developed by bacteria to scavenge nickel in the environment, especially through the structural studies of several Ni-BP. The resolution of the crystal structures of five Ni-BPs from diverse bacteria, in interaction with nickel, led us to identify their nickel-binding sites and shed light on the different binding modes. Our results show that the presence of an exogenous metallophore, called nickelophore, is always required. In vivo studies in Escherichia coli were also conducted, showing that this bacteria seems to be able to synthesize its own nickelophore. In addition, we have solved the crystal structure of Helicobacter pylori HypB in complex with nickel. This result provides insight into its cellular function in nickel enzyme maturation pathways.

Assessment of the impact of landscape structure on the dispersion of lynx in Posumavi Abstract: The big predators are a traditional group of bioindicative species, whose presence shows the state of environment and landscape within a region. As these animals recolonize the cultural landscape of central Europe it's needed to understand their space requirements and habitat preferences. The lynx (Lynx lynx) has been one of the Sumava forest species since the 70's. After almost 40 years the population of lynx has spread from Sumava and Bavarian Forest to forested parts of Cesky Les, Smrcina and Novohradske hory and to both sides of state borders. However today's state of lynx population, stable number of animals or genetic variability is endangered by many factors. Long term viability of the lynx population is - besides poaching or illegal hunting − affected by the loss of suitable habitats and ongoing fragmentation of the landscape. One of the possible solutions of negative impacts is delineation and protection of landscape permeability of habitat corridors. They might have provide supply of new individuals to small, extinction prone population and at the same time they could reinforce overall fitness population. This thesis has three main objectives:1) evaluation of landscape fragmentation and connectivity in...

The aim of this thesis was to identify factors that contribute to invasiveness of species in the genus Impatiens. This genus is horticulturally attractive and includes several species that are known to have naturalized outside their native ranges, while others did not escape, in spite of being frequently cultivated. When looking for traits associated with invasiveness, it is useful to focus on congeneric species. Their traits and dispersal modes are less influenced by phylogeny, than when comparing unrelated species or even complete floras. This helps to account for traits that favour invasive species over native ones and thus identify potential invaders more precisely. A superior invader performance is attributed to a competitive advantage over native species that can lead in extreme case to competitive exclusion of the latter. Invasive and native species com- pete only if their niches overlap and the strength of competition depends on niche similarity. Importantly, invasive species are considered to be able to maintain their high competitiveness over a wide range of environmental conditions, while native ones often have narrower environ- mental optima. Lastly, competitive outcome can vary over life stages and depends on the degree of species dominance, which is rarely taken into account. Spread and...

The requirements of true frogs on breeding sites were monitored at 19 locations in the Hradec Králové Region and the Central Bohemia Region and Vysočina Region. Specific sites were selected according to the high variability. Breeding sites are mutually different representation of true frogs, water volume, depth, water and surrounding vegetation. The data of oviposition three different species of czech frogs - moor frog (Rana arvalis), agile frog (Rana dalmatina) and common frog (Rana temporaria) - were collected in the spring months, from the end of March until the end of April, from 2012 to 2015. During this period were collected data from 927 egg clutches of these species. The data were obtained by non-invasive way - measuring of inividual clutches directly on the reproductive site. At each breeding site was also recorded the required parameters of the breeding pond and the surrounding environment (presence of true frogs, the water volume and depth of the pond, the presence and density of aquatic vegetation, surrounding vegetation, air and water temperature, pH value of water, etc.). The results presented in this work confirm that the three species of true frogs have, in some parameters, different standards to select of breeding sites. This clarification of species- specific claims is also...

This work gives an overview of the composition of the diet of bats in the eastern Mediterranean and the Middle East, discusses the structure of bat communities in different bioregions of the area in terms of hunting strategies and resource partitioning and last but not least, how echolocation and morphological characteristics of bats affect the composition of the diet. Although some samples were relatively small therefore it is necessary to look soberly at their informative value, and thus their importance is undeniable. The study in some cases provides completely the first information regarding the composition of diet in several species. Asellia arabica mainly catches Coleoptera (Scarabaeidae), Triaenops persicus hunts Lepidoptera, but Heteroptera, Coleoptera (Scarabaeidae) and Orthoptera too, while Triaenops parvus is a specialist in hunting Lepidoptera. Rhinopoma muscatellum hunts mainly Formicoidea, followed by Coleoptera (Melolonthinae) and Heteroptera, Rhinopoma hadramauticum hunts Formicoidea. Lepidoptera of different size, Heteroptera and Coleoptera are the prey of Chaerephon nigeriae. Pipistrellus hanaki has a wide niche breadth as other species of the genus Pipistrellus. In this study Brachycera, Auchenorrhyncha and Coleoptera primarily occurred in its diet. Not yet described species of...

This work gives an overview of the composition of the diet of bats in the eastern Mediterranean and the Middle East, discusses the structure of bat communities in different bioregions of the area in terms of hunting strategies and resource partitioning and last but not least, how echolocation and morphological characteristics of bats affect the composition of the diet. Although some samples were relatively small therefore it is necessary to look soberly at their informative value, and thus their importance is undeniable. The study in some cases provides completely the first information regarding the composition of diet in several species. Asellia arabica mainly catches Coleoptera (Scarabaeidae), Triaenops persicus hunts Lepidoptera, but Heteroptera, Coleoptera (Scarabaeidae) and Orthoptera too, while Triaenops parvus is a specialist in hunting Lepidoptera. Rhinopoma muscatellum hunts mainly Formicoidea, followed by Coleoptera (Melolonthinae) and Heteroptera, Rhinopoma hadramauticum hunts Formicoidea. Lepidoptera of different size, Heteroptera and Coleoptera are the prey of Chaerephon nigeriae. Pipistrellus hanaki has a wide niche breadth as other species of the genus Pipistrellus. In this study Brachycera, Auchenorrhyncha and Coleoptera primarily occurred in its diet. Not yet described species of...

Species distribution and composition of bird communities of South Africa is not accidental, but is influenced by environmental conditions, habitat structure, and natural history of the area. Functional traits of the species (morphology, dietary strategies or reproductive parameters) give information on how the individuals interact with the environment they live in. The description of the functional characteristics, expose specific adaptations and the role of the species in the studied ecosystem. On the basis of functional characteristics we are able to estimate functional diversity of studied community. The spatial variability of species and functional diversity allocates longitudinal gradient. Regarding the morphological and reproductive parameters that are continuous in nature and more species- specific, we observe a faster increase in functional diversity. Considering the feeding preferences that are categorical and show a limited number of levels, a modest increase in functional diversity apparent is. Dietary functional diversity is more evenly distributed. Relationship between the functional and species diversity can provide us with information about how species are added to the community or answer the question to what extent the higher number of species requires more ecological space. The...

Light is essential component of forest ecosystem, as limited light availability in forest-floor restricts herb and tree seedlings growth. Importance of light availability for maintaining plant species diversity and community structure wasn't sufficiently evaluated in the Czech Republic. This study focus on the ecological relevance of light availability on both landscape and local scale. Relationship of light to cover, diversity and species composition was quantified in the thesis. Dominant tree species affected light availability and its spatial variability. Light availability was along the soil reaction and slope most influential factor for large-scale species diversity. Within-site light variability affected plant diversity more than soil reaction variability. Measuring light by means of hemispherical photography seems to be an appropriate for studies like this. Light availability influnence on community compostition is weak in comparison with other environmental gradients.