The role of soil microbial diversity and activity in ecosystem functioning

Soil microorganisms and soil organic matter availability regulate soil quality and fertility. Through their activity in biogeochemical cycling processes, soil microorganisms decompose soil organic matter and thus regulate nutrient availability and primary production. Landuse changes, such as a shift from forest to agricultural land, as well as a change in tree species composition, can modify microbial diversity and activity and consequently ecosystem funcitoning. Some parameters can be used as biological indicators, relating land use management to soil functioning and ecosystem services. New molecular tools allow now an in-depth investigation of the role of soil microbial diversity in ecosystem functioning. I will adress biogeochemical cycling processes and their relation
to ecosystem functioning, with particular emphasis on forest ecosystems. Examples will be drawn from recent research projects investigating the links between tree species, tree species diversity, and soil microbial biomass, diversity and activity in temperate and tropical forests.