Sediment export and its controls during secondary forest succession

• Applicant: Professor Dr. Helmut Elsenbeer, since 8/2017
• Subject Area: Physical Geography
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 268351664

The ecological consequences of land-use and land-cover changes have been investigated by numerous scientific studies and are of great interest to the general public because these changes have a direct impact on the daily lives of millions of people. In many tropical countries, old-growth forests are still lost at an alarming rate but at the same time, social shifts and migration into cities result in a substantial increase of secondary succession forests. Understanding the consequences of these large-scale land-cover changes is important both for basic research and land-use planning. Unfortunately, the available scientific literature is strongly biased towards studies dealing with biotic aspects, whereas surprisingly little details are known with respect to changes of erosion processes during secondary forest succession. Moreover, it is currently unknown how forest regrowth controls erosion rates in tropical regions that are naturally prone to the activation of surficial flow paths and soil loss. Due to a mismatch between aboveground and belowground recovery rates, I anticipate that these areas show a peak of sediment export during early stages of secondary forest succession. Testing this hypothesis requires quantifying suspended-sediment exports of catchments on similar soils but covered with different stages of secondary succession vegetation. To achieve my objectives I propose an event-based, automated sampling of suspended sediment at 8 forest sites in various stages of succession. The proposed sediment sampling campaign will be accompanied by a monitoring of the drainage network expansion during rainfall events and detailed field investigations of forest structure and soil parameters. These field data and state-of-the-art statistical modeling of sediment export will allow me to assess the change of erosion processes during secondary forest succession and to identify the drivers of the observed changes of erosion processes. I expect that the results of the proposed research will trigger a debate on the temporal and spatial variability of erosion processes in forest ecosystems. Given the large area which is subject to forest succession in tropical countries, the findings of the proposed work are not only of scientific interest but they are also - in the context of water-quality management - of socio-economic relevance.

• DFG Programme: Research Grants
• International Connection: Panama
• Cooperation Partner: Jefferson S. Hall, Ph.D.
• Ehemaliger Antragsteller: Dr. Alexander Zimmermann, until 8/2017