0000000000039959
AUTHOR
Sandra Lavorel
Influence of plant traits, soil microbial properties, and abiotic parameters on nitrogen turnover of grassland ecosystems
International audience; Although it is known that multiple interactions among plant functional traits, microbial properties , and abiotic soil parameters influence the nutrient turnover, the relative contribution of each of these groups of variables is poorly understood. We manipulated grassland plant functional composition and soil nitrogen (N) availability in a multisite mesocosm experiment to quantify their relative effects on soil N turnover. Overall, root traits, arbuscular mycorrhizal colonization, denitrification potential, as well as N availability and water availability, best explained the variation in measured ecosystem properties, especially the trade-off between nutrient sequest…
Plant species identities and fertilization influence on arbuscular mycorrhizal fungal colonisation and soil bacterial activities
International audience; Plant species influence soil microbial communities, mainly through their functional traits. However, mechanisms underlying these effects are not well understood, and in particular how plant/ microorganism interactions are affected by plant identities and/or environmental conditions. Here, we performed a greenhouse experiment to assess the effects of three plant species on arbuscular mycorrhizal fungal (AMF) colonization, bacterial potential nitrification (PNA) and denitrification activities (PDA) through their functional traits related to nitrogen acquisition and turnover. Three species with contrasting functional traits and strategies (from exploitative to conservat…
A multi-site study to classify semi-natural grassland types
International audience; Calibration and validation of simulation models describing herbage growth or feed quality of seminatural grasslands is a complex task for agronomists without investing effort into botanical surveys. To facilitate such modelling efforts, a limited number of grassland types were identified using a functional classification of species. These grassland types were characterized by three descriptors required to model herbage growth or feed quality: the abundance-weighted mean leaf dry matter content across grass species, the relative abundance of grasses, and an estimate of species richness. We conducted a multi-site analysis over 749 grasslands from eight temperate region…
Effects of mowing on fungal endophytes and arbuscular mycorrhizal fungi in subalpine grasslands
International audience; In French subalpine grasslands, cessation of mowing promotes dominance of Festuca paniculata, which alters plant diversity and ecosystem functioning. One of the mechanisms underpinning such effects may be linked to simultaneous changes in the abundance of fungal symbionts such as endophytes and arbuscular mycorrhizal fungi. In field conditions, mowing reduced the abundance of the endophyte Neotyphodium sp. in leaves of F. paniculata by a factor of 6, and increased mycorrhizal densities by a factor of 15 in the soil. In greenhouse experiments, the mycorrhizal colonization of Trifolium pratense and Allium porrum increased 3- fold and 3.8- fold respectively in mown vs u…
Responses of above- and below-ground fungal symbionts to cessation of mowing in subalpine grassland
Abstract The cessation of mowing in subalpine grasslands promotes the dominance of Festuca paniculata leading to the reduction in plant diversity. Moreover, it affects positively the abundance of Epichloe sp. inhabiting F. paniculata leaves and negatively the soil density of arbuscular mycorrhizal fungi (AMF). We explored how the cessation of mowing influences root AMF communities in F. paniculata and the neighboring plants, and Epichloe sp alkaloids. Thirteen AMF operational taxonomical units were found. The neighboring plants affected positively the abundances of Aalpin and GLOM_7 whereas the interaction plant/management type influenced significantly Claroide_1 , GLOM_1 and GLOM_7 . The N…