Structure and functioning of the decomposer system in lowland rainforest transformation systems

The aim of subproject B08 is the in detail analysis of the decomposer system in different rainforest transformation systems in Southern Sumatra. We try to acquire in detail knowledge on its driving factors and how it is affected by rainforest transformation. The decomposer system is a diverse food web consisting of microbial decomposers and soil animals, which is sustained by the nutrients provided by dead plant litter material. The decomposer system recycles and remobilizes these nutrients and therefore is of central importance for ecosystem functioning. The descriptive part of our research focuses on the diversity and species composition of microbial feeding protozoans (testate amoeba) and microarthropods (Oribatida, Collembola, Mesostigmata), key players in the food webs of soil and litter. We compare the community structure of semi natural secondary forests with the transformation systems jungle rubber, rubber monocultures and oil palm plantations, which represent stages of increasing anthropogenic land use. By additionally using experimental approaches, e.g., by manipulating leaf litter quality in litter bags, excluding predators (e.g. ants) or fine roots, we investigate how decomposition processes are affected by bottom-up and top-down forces and evaluate the contribution of roots and mycorrhizal fungi to the nutrition of soil animals.

• Klarner, B., Ehnes, R. B., Erdmann, G., Eitzinger, B., Pollierer, M. M., Maraun, M. & Scheu, S. (2014) Trophic shift of soil animal species with forest type as indicated by stable isotope analysis. Oikos. DOI: 10.1111/j.1600-0706.2013.00939.x
• Ehnes, R. B., Pollierer, M. M., Erdmann, G., Klarner, B., Eitzinger, B., Digel, C., Ott, D., Maraun, M., Scheu, S. & Brose, U. (2014) Lack of energetic equivalence in forest soil invertebrates. Ecology, 95, 527-37.
• Digel, C., Riede, J. O., Curtsdotter, A., Klarner, B. & Brose, U. (2014) Unraveling the complex structure of forest soil food webs: higher omnivory and more trophic levels. Oikos, in press.
• Klarner, B., Maraun, M. & Scheu, S. (2013) Trophic diversity and niche partitioning in a species rich predator guild - Natural variations in stable isotope ratios (C-13/C-12, N-15/N-14) of mesostigmatid mites (Acari, Mesostigmata) from Central European beech forests. Soil Biology & Biochemistry, 57, 327-333.
• Birkhofer, K., Schöning, I., Alt, F., Herold, N., Klarner, B., Maraun, M., Marhan, S., Oelmann, Y., Wubet, T., Yurkov, A., Begerow, D., Berner, D., Buscot, F., Daniel, R., Diekötter, T., Ehnes, R. B., Erdmann, G., Fischer, C., Foesel, B., Groh, J., Gutknecht, J., Kandeler, E., Lang, C., Lohaus, G., Meyer, A., Nacke, H., Näther, A., Overmann, J., Polle, A., Pollierer, M. M., Scheu, S., Schloter, M., Schulze, E.-D., Schulze, W., Weinert, J., Weisser, W. W., Wolters, V. & Schrumpf, M. (2012) General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types. Plos One, 7, e43292.
• Eisenhauer, N., Milcu, A., Sabais, A. C. W., Bessler, H., Brenner, J., Engels, C., Klarner, B., Maraun, M., Partsch, S., Roscher, C., Schonert, F., Temperton, V. M., Thomisch, K., Weigelt, A., Weisser, W. W. & Scheu, S. (2011) Plant Diversity Surpasses Plant Functional Groups and Plant Productivity as Driver of Soil Biota in the Long Term. Plos One, 6, e16055.