Effects of inter and intraspecific diversity and genetic divergence of aquatic fungal communities on leaf litter decomposition-a microcosm experiment

Abstract

Freshwater fungi play a key role in plant litter decomposition and have been used to investigate the relationships betweenbiodiversity and ecosystem functioning in streams. Although there is evidence of positive effects of biodiversity onecosystem processes, particularly on biomass produced, some studies have shown that neutral or negative effects mayoccur. We manipulated the composition and the number of species and genotypes in aquatic fungal assemblages creatingdifferent levels of genetic divergence to assess effects of fungal diversity on biomass produced and leaf decomposition.Generally, diversity effects on fungal biomass produced were positive, suggesting complementarity between species, but inassemblages with more species positive diversity effects were reduced. Genotype diversity and genetic divergence had netpositive effects on leaf mass loss, but in assemblages with higher diversity leaf decomposition decreased. Our resultshighlight the importance of considering multiple biodiversity measures when investigating the relationship betweenbiodiversity and ecosystem functioning.