European semi-natural grasslands are among the most species rich habitats in the world. They were historically shaped by anthropogenic land use and developed their species and genetic variation alongside the agricultural practices of the time. The lasting effects of historic processes can be ob-served until today, however recent global developments are affecting this diversity in an unprece-dented intensity and frequency. The present study aims to investigate the effects of land use his-tory,

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... ndscape structure as well as vegetation and habitat characteristics on genetic and epigenetic variation of common grassland species from different grassland habitats. Chapter One introduces the scientific context the present thesis is placed in. Processes shaping biodiversity, the characteristics of the grassland ecosystems studied in this thesis and the history of grassland ecosystems in general is reviewed. Finally, grassland habitats are discussed in the context of biodiversity and conservation. In Chapter Two and Three the influence of land use history, landscape structure and habitat quality on the genetic variation of typical grassland species from oat-grass and litter meadows was investi-gated. We used Amplified Fragment Length Polymorphism (AFLP) analyses to estimate genetic diversity and differentiation among populations from ancient and recent grasslands. Chapter Two describes the genetic variation patterns of three typical grassland species (Dactylis glomerata L., s. I., Heracleum sphondylium L. & Trifolium pratense L.), studied in oat-grass mead-ows. Each species was influenced by different explanatory variables, but most interestingly current landscape structure and habitat quality, i.e. the amount of litter, influenced genetic diversity in this grassland habitat. Historic landscape structure and land use history were of minor interest in this comparably recently established grassland type. Similarly, Chapter Three deals with the genetic variation in litter meadow plant species (Angelica sylvestris L., Fil [...]