ABSTRACT
This chapter shows that nival and alpine plant distributions can be separated, not only according to community patterns, but can also be correlated to basic habitat features, e.g. temperature and snowcover duration. Temperature is the outstanding driving factor which triggers the altitudinal turnover of species and vegetation types in mountain systems. The various aspects of the temperature regime, however, influence mountain plant distribution patterns differently. Depending on the respective situation, they are more or less threatened by climate warming. This is important for any global account of mountain biodiversity and its possible changes. Climate change scenarios suggest that, as a consequence of earlier snowmelt and/or warming, alpine species may fill the nival niche, putting strong pressure on the less competitive nival species. In the international literature the term alpine is commonly used to describe the uppermost vegetation zone of high mountain systems, from the treeline upwards to the limits of plant life.
