FluBig: Fluvial Biogeomorphology across Multiple Scales

• Applicants: Dr. Florian Betz; Professor Dr. Gregory Egger
• Subject Area: Physical Geography
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 522097137

Riverine landscapes are shaped by the feedbacks between hydrological, geomorphological and ecological processes. These feedbacks are happening across multiple scales, from the scale of single plants modifying the hydraulic forces around it to the formation of landforms like islands which in turn lead to the emergence of specific river types such as braided or anastomising. Over the past years, the growing field of biogeomorphology has improved the understanding of the interaction of vegetation and (hydro-) morphological processes. Despite recent scientific progress, research gaps remain. In particular, the functioning of this interaction across multiple scales remains poorly understood. This arises also from the fact that the majority of studies in fluvial biogeomorphology have been carried out on the scales of geomorphological units or smaller study reaches causing a lack of knowledge about larger scales. With the recent progress in remote sensing and the advent of satellite missions like Sentinel-2, there is for the first time data available which has a suitable spatial and temporal resolution as well as spatial coverage to complement field based research and UAV data to multi-scale biogeomorphological research. With FluBig, we aim to make use of established methods on smaller scales and exploit the recent progress in remote sensing for large scale observation. The overall objective is to understand the feedbacks between hydro-geomorphology and vegetation across multiple scales. Focus is the question, how small scale feedback mechanisms on the scales of river elements or hydraulic units influence the structures and processes on the scales of geomorphological units, reaches or even the entire river corridor and vice versa. We base upon the concept of panarchy and investigate the adaptive cycles and their linkages on these different scales. Case study is the Naryn River in Kyrgyzstan. This is a still free flowing river on length of more than 600 km. Its large dimension along with high natural dynamics and diversity of river types along the longitudinal profile make this river an ideal case study for FluBig. To achieve the objectives, we combine field methods for mapping vegetation traits and geomorphic characteristics with UAV surveys and innovative remote satellite remote sensing to quantify adaptive cycles on different scales. Afterwards, panarchies are constructed and operationalized for different river types occurring in the Naryn River corridor. With this research, we quantify for the first time biogeomorphological feedbacks in river corridors across multiple scales. This advances the understanding of the emergence of riverine landscape and helps to develop nature based solutions in river management.

• DFG Programme: Research Grants