Mycorrhizal fungi form mutualistic interactions with plant roots and function as key link for nutrient exchange between the above- and belowground compartment. In tropical lowland rainforests most tree species are associated with arbuscular mycorrhizal fungi (AMF). Some species-rich tree families, such as Dipterocarpaceae form ectomycorrhizal (EM) associations. This may give a competitive advantage to members of this family with respect to nitrogen acquisition from organic materials such as litter. Transformation of primary forests into intensely managed plantations leads not only to a loss in tree species diversity but presumably also to a loss in mycorrhizal diversity. However, these changes have not yet been quantified and their consequences for ecosystem services such as nutrient uptake from or carbon transfer into the soil are not known. In the present study we aim to understand how transformation of tropical lowland rain forests into rubber and oil palms plantations influences the diversity and functionality of mycorrhizal fungal and soil fungal communities with respect to tree nutrition.

To test the hypothesis (see B07) my Indonesian colleague Edy Nur and I take soil samples in the different transformation systems and the rainforest reference sides. First processing is done at UNJA as sieving, measurement of fresh and dry biomass of roots, measurement of water and residual water content of soil, root tip counting and freeze-drying of samples to transport them to Germany. In Göttingen Edy Nur will basically work on host-preferences (Sanger sequencing). My work will focus on comparing fungal diversity in roots and soil between the different transformation systems and forest sides (Pyrosequencing) as well as relations between nutrient contents of root and soil to fungal diversity.
Based on results for the fungal diversity we are going to do experiments about inorganic (short term) and organic (long term) nitrogen uptake in using 15N-labelled solutions respectively litter.