Glacier Forelands – Unique Field Laboratories for the Study of Primary Succession of Plants

While receding glaciers in several respects are related to negative consequences for resident people down river (e.g., water security, glacial lake outburst floods, etc.), from an ecological point of view, they are unique field laboratories to study vegetation development and dynamics from the very beginning. As the bare ground exposed by the receding glaciers generally does not provide a seed bank, the colonization of formerly ice-covered ground represents a true primary succession. There are two different approaches to study vegetation dynamics in glacier forelands: permanent plots and chronosequences ("space for time substitution"). As both procedures have their respective pros and cons, they should not be regarded to be mutually exclusive; rather, they should complement each other for a comprehensive understanding of the vegetation dynamics in glacier forelands. This chapter gives a general overview on patterns and processes of vegetation development in glacier forelands based on vegetation sampling in two glacier forelands of the Eastern Alps employing both abovementioned approaches. Sampling records groundcover of all vascular plants, structural features such as life form composition and dispersal biology types of the species as well as site characteristics. The two different approaches give evidence for both the early vegetation dynamics after deglaciation by the permanent plot studies and for potential future developments by the chronosequences.