title: Magnitude and variability of process rates in fungal diversity-litter decomposition relationships.
abstract: There is compelling evidence that losses in plant diversity can alter ecosystem functioning, particularly by reducing primary production. However, impacts of biodiversity loss on decomposition, the complementary process in the carbon cycle, are highly uncertain. By manipulating fungal decomposer diversity in stream microcosm experiments we found that rates of litter decomposition and associated fungal spore production are unaffected by changes in decomposer diversity under benign and harsher environmental conditions. This result calls for caution when generalizing outcomes of biodiversity experiments across systems. In contrast to their magnitude, the variability of process rates among communities increased when species numbers were reduced. This was most likely caused by a portfolio effect (i.e. statistical averaging), with the uneven species distribution typical of natural communities tending to weaken that effect. Curbing species extinctions to maintain ecosystem functioning thus can be important even in situations where process rates are unaffected.
authors.affiliation: Laboratoire Dynamique de la Biodiversité, UMR 5172 CNRS-UPS, 29, rue Jeanne Marvig, 31055 Toulouse Cedex, France Department of Limnology, Eawag/ETH, 6047 Kastanienbaum, Switzerland.
authors.forename: Christian K
authors.initials: CK
authors.lastname: Dang
authors.forename: Eric
authors.initials: E
authors.lastname: Chauvet
authors.forename: Mark O
authors.initials: MO
authors.lastname: Gessner