BioScapes IV: Biotic effects on sediment storage and connectivity in river catchments across timescales.

 

Investigator Names and Contact Info:

• Thomas Hoffmann (Geomorphology). Bundesanstalt für Gewässerkunde, University Bonn, Germany
• Lothar Schrott (Geomorphology). University Bonn, Germany
• Sebastian Schmidtlein (Vegetation dynamics). Karlsruher Institut für Technologie (KIT), Germany
• Fabian Fassnacht (Vegetation remote sensing). Karlsruher Institut für Technologie (KIT), Germany

 

Chilean Collaborators Involved:

• Luca Mao (Geomorphology). Pontificia Universidad Catolica de Chile
• Felipe Aburto (Pedology, Biogeochemistry). Universidad de Cocepción, Chile
• Javier Lopatin (LIDAR remote sensing). University of Chile, now at KIT, Germany

 

Modelling and budgeting sediment transport, storage and connecticity - biotic effect

 

PhD-Student:

• Simon Terweh. Federal Institute of Hydrology Koblenz, Germany

66% Co-Supervisor: PD Dr. Thomas Hoffmann, 33% Co-supervisor: Prof. Lothar Schrott

 

 

The Influence of vegetation on erosion and sediment connectivity - a remote sensing based analysis on the catchment scale

 

MSc-Student:

• Kerstin Kleinohl. University of Bonn, Germany

supervisor: PD Dr. Thomas Hoffmann / Prof. Lothar Schrott, co-supervisor: Dr. Sebastian Schmidtlein

 

 

Interactions of Vegetation, Sediment Connectivity and Erosion – a remote sensing approach

 

MSc-Student:

• Johannes Senn. University of Bonn, Germany

supervisor: Dr. Sebastian Schmidtlein

 

 

Project Summary:

BioScapes IV is part of a series of independent EARTHSHAPE proposals that quantifies biotic, surface process, and paleoclimate interactions at the catchment scale and larger. In This contribution, we analyse the evolution of the earth surface, which 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. 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 at understanding temporal and spatial effects of vegetation and other biotic processes on sediment dynamics in the three focus catchments of EarthShape. Along the flow path of water, sediment delivery and storage will be assessed on different spatiotemporal scales including individual hillslopes and entire river catchments, from ~20 ka BP to the present.

The study combines data from geomorphological and stratigraphical mapping, geophysical soundings and OSL and radiocarbon dating. This information will be used to compile a long-term sediment storage inventory and to calculate sediment budgets and residence times, as a proxy of sediment connectivity. To differentiate the direct (short-term) effects of the vegetation patterns on recent sediment storage and connectivity from long-term topographic effects of vegetation mediated weathering and transport, we will use a straightforward connectivity algorithm and evaluate the results based on the geomorphic mapping and the results of the long-term sediment budget.

In summary, the proposed project will deepen our understanding of non-linear responses to external drivers in ecogeomorphological systems through a combination of geomorphological and biogeographical techniques. The major focus lies on sediment storage and residence time, which are central measures of catchment connectivity and thus of the sensitivity of sediment cascades in response to external environmental changes.