Nutrient turnover, greenhouse gas exchange and biodiversity in natural forests of Central Europe

Dordrecht

2005

Sonderdruck

200120771

We measured the microbial turnover of carbon (C) and nitrogen (N) in 12 natural forest reserves in Austria, along with estimating potential emission rates of nitrous oxide (N2O) and carbon dioxide (CO2), and uptake rates of methane (CH4). The community composition of soil microorganisms was investigated using PLFA (Phospholipid fatty acid) analysis and molecular tools. The biodiversity of selected taxa of micro-, meso- and macrofauna were studied. The aim was to provide a reference data set for the evaluation of the soil biology in managed, especially disturbed or damaged forest ecosystems. Ecophysiological quotients were tested for their ability to make predictions about the carbon dynamics of forest soils. The 12 forests represented the six typical forest types in Central Europe: oak, beech, spruce-fir-beech, floodplain, and pine forests. Nitrogen turover rates were high in soils with sufficient soil moisture and high pH. Nitrogen losses as nitrate or N2O were small unless N deposition was as high as 30 kg ha-1 yr-1. The fastest turnover of C and N occurred in the floodplain forests, based on microbial quotients, xylanase activity, the relative thickness of litter layer and 15N abundance in the organic soil. Carbon turnover was slowest in the beech forests on acidic bedrock, and slow turnover may lead to the largest net C accumulation. Tree species had distinct effects on microbial community composition, but the high soil biodiversity in these natural forests may not be greater than in managed forests.