Biogeomorphic dynamics in the Turtmann glacier forefield, Switzerland

• Main Author: Eichel, Jana
• Other Authors: Dikau, Richard, Schmidtlein, Sebastian
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universitäts- und Landesbibliothek Bonn 2017
• Subjects: Biogeomorphologie; Gletschervorfeld; Moränen; Paraglazial; Sukzession; Hierarchietheorie; Solifluktion; Ökosystem; Geomorphologie; Vegetationsdynamik; biogeomorphology; ecogeomorphology; glacier foreland; moraines; paraglacial; vegetation succession; ecosystem engineer; solifluction; hierarchy theory; panarchy; scales; ddc:550; ddc:570; ddc:580; ddc:910; Dryas octopetala
• Online Access: https://hdl.handle.net/20.500.11811/7168

Worldwide, glacier retreat enlarges glacier foreland areas, which are characterized by pronounced geomorphic and ecologic dynamics. Feedbacks between these dynamics are believed to drive glacier foreland landscape development, yet, they are only poorly understood. The aim of this thesis is to enhance the understanding of feedbacks between geomorphic processes and plants in glacier forelands, especially on lateral moraine slopes, through a hierarchical, scale-based biogeomorphic approach. Based on geomorphic and ecologic data from Turtmann glacier foreland (Switzerland), biogeomorphic feedbacks on different spatiotemporal scales are investigated and finally linked in a panarchy approach. On a small scale, the dwarf shrub Dryas octopetala L. is identified as ecosystem engineer. Through its adapted root- and above ground biomass traits, it changes mechanical, thermal, hydrological and chemical material and surface properties. Thereby, it influences occurring geomorphic processes, facilitates species establishment and advances soil development. On an intermediate scale, the relationship between geomorphic process frequency and magnitude and plant species resilience and resistance determines the biogeomorphic feedback window in which feedbacks can occur. In this window, ecosystem engineering by D. octopetala can produce turf-banked solifluction lobes (TBLs) as biogeomorphic structures. This process is described in a conceptual biogeomorphic model of TBL development. On a long timescale, paraglacial adjustment and vegetation succession interact in a biogeomorphic succession, during which biogeomorphic feedbacks promote the decrease of paraglacial processes and the increase of biotic interactions. On a large spatial scale, lateral moraine slopes are characterized by a mosaic of linked geomorphic and vegetation patches, in which biogeomorphic succession proceeds. Large magnitude geomorphic processes and ecosystem engineering create new patches and thereby change the patch mosaic during biogeomorphic patch dynamics. ...