Mechanisms of soil erosion, soil properties and Ecoscape analysis as a function of species richness and species composition in subtropical forests

Project: Research

Project participants

  • Aßmann, Thorsten (Project manager, academic)
  • Kühn, Peter (Project manager, academic)
  • Scholten, Thomas (Project manager, academic)
  • Schmidt, Karsten (Project manager, academic)
Soil erosion is a major threat resulting in soil degradation and loss of soil and ecosystem functions. Our previous research in the framework of BEF-China shows that soil loss in general and matter fluxes with sediment discharge and overland flow are related to tree diversity. We ask to which extend carbon, nitrogen, phosphorous (CNP) and sediment fluxes are driven by both biodiversity effects and ground cover by biological soil crusts (BSC) and plant litter of the topsoil, along with general ecoscape properties like slope, curvature and soil properties. We assume that type and extent of ground cover and their role for soil erosion change over time with tree growth from biological soil crusts (BSC) and bare ground to a complete litter cover. This will cause changes in CNP and sediment fluxes along with biodiversity effects. Outgoing CNP fluxes are negatively related to tree growth and increasing ground cover by litter since the kinetic energy of raindrops is captured by litter cover and less CNP is washed-off by sediment discharge. Furthermore, higher tree diversity can promote the diversity of associated organisms, especially the litter decomposing macrofauna. To address these questions, runoff plots will be used as measuring device. The measurements in the Main Experiment of BEF-China will include surface runoff, sediment discharge, and particular and solute transport of CNP.First results indicate significant relations between spatial domains of soil and site properties and growth patterns of trees. We will delineate and analyse environmental co-variables for each plot, population and individual to control for environmental heterogeneity when testing biodiversity effects by defining a set of spatially homogenous response units as smallest components of the ecoscape at large. Such soil-ecological response units cover a unique set of spatial and temporal scale-free environmental variables that result from interrelations between soil, plant, topography and climate. Data mining techniques and multi-regression analysis will be applied in terms of integrated soil-microclimate-ecosystem-functioning analysis and modeling and to construct the full ecoscape across scales.Further studies of SP 6 will account for soil properties of the VIPs, especially heavy metals and soil CNP. Reading and maintenance of the erosion sticks in the CSPs and the Main Experiment will continue. Additional measurements in the Main Experiment will be done to continue the base line study of soil properties in order to account for changes in soil CNP stocks, soil acidity and exchangeable cations over time and their relation to a growing forest and biodiversity effects to feed the Ecoscape approach in Z1.
Name of research programmeFunded by the German Research Foundation (DFG) Research Group FOR 891: The role of tree and shrub diversity for production, erosion control, element cycling, and species conservation in Chinese subtropical forest ecosystems<br/>