My study of Environmental Sciences at the Swiss Federal Institute of Technology (ETH) Zurich was followed by a doctorate at the Geobotanical Institute of the same University. My early research at that time focused on the spread and establishment of introduced evergreen broad-leaved species in lowland deciduous forests in southern Switzerland as well as the driving forces of these processes.

“Putting together a compelling number of case studies, we could show that whatever ecosystem or geographic region is considered, the ecological responses to recent climate change become increasingly evident.”

Afterwards, I received a position as a scientific assistant at the Institute of Geobotany of the University of Hannover, where I extended the focus of my climate impact studies to other regions (e.g., northern range margin of holly [Ilex aquifolium] in northern Germany and southern Scandinavia) and to other habitats (e.g., alpine summit flora in the Bernina area [European Alps]). These were also the elements of my habilitation thesis on climate-induced vegetation shifts along altitudinal and latitudinal gradients. My present position is Senior Academic Advisor at the Department of Plant Ecology at the University of Bayreuth (Germany).

From the beginning, I was interested in global processes and their impacts on species and communities. As my early research focused on range shifts of thermophilous evergreen broad-leaved species, the link to global warming was obvious. Since then, the more I am involved in climate impact research, the more fascinated I become, and it seems that the passion grows in parallel with the trend and magnitude of the global warming we are about to experience. The fact "that we have entered a period of consequences" (Al Gore, 2006) makes it particularly challenging for real-time climate impact studies.

Until the end of the 20^th century, the discussion about ecological responses to climate change was dominated by modeling studies of expected impacts by 2050 or even later, although there was a substantial and increasing number of observed recent impacts. With this review paper, we aimed at putting together the knowledge scattered across various journals. Putting together a compelling number of case studies, we could show that whatever ecosystem or geographic region is considered, the ecological responses to recent climate change become increasingly evident. The implications of this review, and other papers which followed afterwards, was that there is growing perception that climate change is not something that will happen in the future but is already in progress and we are able to monitor the impacts. So it is not the single response of a particular species but the whole suite of species’ responses pointing in the same direction that provides evidence.

These papers deal with different evergreen broad-leaved species and their ability to colonize new areas in the past few decades. They illustrate the sort of changes we might expect with a warmer climate and may contribute to a better understanding of the processes of shifting species’ ranges, changing community composition, and ecosystem structure. No matter what ecosystem you look at, terrestrial or aquatic, it is very likely you will find such changes reflecting recent climate change. However—and this might be another important aspect of these papers—it is necessary for these sort of impact studies to have a reliable and repeatable data source from the past which then can be applied and updated for the present.