Biogeomorphic feedbacks and their role for sediment erosion and connectivity along a climatic gradient in Chile

• Applicants: Dr. Jana Eichel; Privatdozent Dr. Thomas Hoffmann; Professor Dr. Sebastian Schmidtlein; Professor Dr. Lothar Schrott
• Subject Area: Physical Geography ; Palaeontology
• Term: from 2015 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280532054

The evolution of the earth surface is governed by i) physical and chemical weathering, ii) hillslope and channel erosion, and iii) transport and deposition of sediment. Biota, and most prominent vegetation, plays a crucial role in all three processes and in turn is effected by these processes. Depending on the timescale, biota can increase or decrease the rates of earth surface processes. In the context of plants as ecosystem engineers, sediment deposition is of special importance since it generates high productivity habitats and thus facilitates the establishment of new vegetation, which in turn modifies earth surface processes. Understanding the response of the earth surface to environmental changes at various time scales thus requires a detailed knowledge on the interaction between earth surface processes and vegetation dynamics.This project aims to understand biogeomorphological feedbacks and how they affect sediment dynamics in the four focus catchments along the climate gradient of Chile. We will study vegetation and soil properties, and geomorphic dynamics along the flow path of water. The study combines data from vegetation geography, geomorphological mapping, high resolution topographic surveys, sediment monitoring at the outlet of the catchments and the GIS-based modelling of sediment connectivity and the numerical sediment flux modelling (using Erosion3D). This information will be used to achieve a patter representation of vegetation dynamics in geomorphic models and to compile contemporary sediments budgets of the four focus catchments. In conjunction with the first phase of this project in EarthShape, which focuses on long-term sediment storage inventory and budgets, we are able to differentiate the direct (short-term) effects of the vegetation patterns on sediment retention and connectivity from long-term topographic effects of vegetation mediated weathering and transport. In summary, the proposed project will deepen our understanding of the changing biogeomorphic feedbacks and the non-linear responses of biogeomorphic systems to external drivers through a combination of geomorphological and biogeographical techniques.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1803: EarthShape: Earth Surface Shaping by Biota
• International Connection: Austria, Chile, Netherlands
• Cooperation Partners: Professor Dr. Felipe Aburto, Ph.D.; Dr. Joachim Götz; Javier Lopatin; Professor Dr. Luca Mao; Professor Dr. Jürgen Schmidt