Effects of increased temperature and aquatic fungal diversity on litter decomposition

Climate warming and biodiversity loss are two major factors threatening freshwaters. Aquatic hyphomycetes are fungi that play a key role in organic matter turnover in streams. To assess the impacts of temperature increase and aquatic hyphomycete diversity on plant-litter decomposition, we manipulated fungal assemblage composition at two levels of diversity (four and eight species) under ambient temperature of 16 degrees C and two regimes of temperature increase differing in 8 degrees C: abrupt versus gradual increase from 16 to 24 degrees C. The effects were evaluated on leaf-litter decomposition, fungal biomass and reproduction. Results showed faster leaf decomposition under increased temperature, but no differences were found between an abrupt and a gradual increase in temperature. Assemblage composition was the major factor controlling fungal biomass and reproduction, while fungal diversity was only critical to maintain reproduction. (c) 2012 Elsevier Ltd and The British Mycological Society. All rights reserved.