A3 Nutrient supply as driver of biomass production and associated ecosystem water fluxes along a land-use and climate gradient [funded by DFG]
PI(s) for this project:
The Research Unit RESPECT intends to integrate a hydrological, a dynamic vegetation, and a climatological model into a land surface model for the tropical montane forest to improve climate modeling. In the focus of the modeling efforts are evapotranspiration and biomass production.
Environmental changes and altered ecosystem processes in a tropical montane forest in Ecuador between 1998 and 2010.
The subproject A3 will provide necessary data for model forcing (soil texture, soil depth, soil water-holding capacity, N deposition, soil P status) and for model evaluation (C and N concentrations and N mineralization rates) collected in this proposed and previous projects in the study area in Ecuador. Furthermore, the subproject A3 will investigate the influence of land use and climate on N mineralization, nutrient release by weathering and nutrient leaching based on the joint core plot design of the Research Unit, which makes use of space-for-time-substitution.
We will focus on all core plots of the humid part of the research area in the first phase of RESPECT, in line with all other subprojects. We will provide basic soil properties and will determine N mineralization rates with a short-term incubation and by measuring the vertical distribution of delta13C values and C concentrations in soil. Furthermore, we will quantify weathering rates by using open-system mass balances, with a pHstat approach (i.e. accelerated weathering at constant pH in the laboratory), and by measuring the vertical distribution of stable Ca isotope ratios in soil as a novel potential indicator of weathering. Finally, we will determine an index of nutrient leaching with the help of ion-exchange bags.
All data will be provided at the core plot and plant functional type level and part of the data even at the level of the joint individual target plants thereby contributing to the joint response-effect framework analysis. The subproject A3 will deepen our understanding of the effect of climate and land-use change on major nutrient supply and loss processes in a highly biodiverse, remote tropical montane forest vulnerable to improved nutrient availability and its anthropogenic replacement systems.