Tundra ecosystems are seriously affected by global climate change. Understanding tundra history and postglacial development may enhance the ability of biologists to anticipate biotic responses to current environmental changes. In this book, the authors analyze changes which have occurred in a vegetative cover and aboveground fauna of vertebrates at Yamal peninsula, one of the greatest plains on the globe. The authors also evaluate pedogenetic processes, soil nutrient status and plant distribution along an elevation gradient in the alpine tundra in the western Italian Alps. In addition, treeline ecotone is a belt of transition from forest vegetation to a nonforest one, which allow the monitoring of climate change. In this book, carbon deposition on the forests of two treeline ecotones is studied. Some of the current emerging theories, models and recent empirical evidence for the dynamics of these reciprocal interactions between climate and terrestrial microbial communities are also reviewed, with particular attention to biogeochemical and ecological perspectives.