Common Patterns and Diverging Trajectories in Primary Succession of Plants in Eastern Alpine Glacier Forelands

Abstract

This paper deals with the vegetation development in four glacier forelands, aligned along a distance of 250 km from West to East in the siliceous Eastern Central Alps. The study employs a chronosequence approach, which assumes a temporal sequence in vegetation development by spatially different sites regarding time since deglaciation. The chronosequences cover the area between Little Ice Age (LIA) maximum glacier extent around 1850, and the current glacier terminus. Despite some shortcomings, chronosequences allow the identification of general patterns of primary succession of plants as a function of site age and local environmental conditions, e.g., changes in species richness, ground cover, plant functional traits, and community structure. While there is no shortage of chronosequence studies in glacier forelands of the Alps, a straightforward comparison aimed at the deduction of general successional trajectories is tricky, due to different procedures of vegetation sampling and data analyses. The comparative examination by a standardized sampling and analyzing protocol of four glacier forelands in the Eastern Central Alps presented here proves the existence of several common patterns in primary succession, but also diverging successional trajectories from West to East. While the pioneer stage in all glacier forelands is similar both floristically and structurally, from the early successional stage onwards, differences increase, leading to different phases in the late successional stage, which is shrub dominated throughout in the westernmost study site, herb–grass–dwarfshrub dominated throughout in the easternmost study site, and divided into an earlier herb–grass–dwarfshrub phase and a later shrub phase in the two study sites in between.

Practice Must Be Backed up by Theory! A Special Issue on Plant Community Ecology

“…To challenge our comprehension of plant communities, we need to test strategies and hypotheses (e.g., environmental filtering hypothesis vs. niche divergence, [3]). The adoption of standardized methods and protocols to analyse data allowed us to untangle and describe the general successional trajectories of chronosequence studies in the Alps' glacier forelands [4]. Nevertheless, we must recognize that since new methods are continuously proposed in modern plant community ecology studies, we can benefit from the integration of new instruments with long consolidated, traditional approaches.…”

“…Investigating the links between biodiversity and ecosystem functioning across spatial scales and rapid global change is a priority to identify management responses that will retain diverse, functioning systems. Fickert [4] employs a chronosequence approach, which assumes a temporal sequence in vegetation development by spatially different sites, ranging from the Eastern to Western Alps, regarding the time since deglaciation. The chronosequences cover a time span ranging between the maximum glacier extent in around 1850 and the current glacier terminus.…”

Dynamics of nitrogen and phosphorus accumulation and their stoichiometry along a chronosequence of forest primary succession in the Hailuogou Glacier retreat area, eastern Tibetan Plateau

“…These contrary results for the N accumulation in soil were mainly found during secondary succession, indicating that the influence of previous vegetation and soil may not be easily excluded. However, primary succession develops forest communities in previously non-vegetated areas, which are typically not affected by human or historical factors [20][21][22][23]. Therefore, studying primary succession will further our understanding of the dynamics of N accumulation under natural conditions.…”

Spatial and temporal dynamics of growth of woody plant species (birch and willows) on the foreland of a retreating glacier in southern Iceland

“…Forelands exposed by the retreat of glaciers following the conclusion of the Little Ice Age have long been considered optimal settings for the study of rates and processes of landscape modification through floral colonization and pedogenesis (see review in Matthews 1992). As described by Fickert (2017Fickert ( , 2020, glacial forelands are indeed the ideal settings to investigate a number of aspects of succession, including the rate of colonization, the linearity (or nonlinearity) of colonization trends, the effects of interspecies competition in driving community composition, and the importance of local site conditions in determining both colonization order and later community diversity.…”