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Background and Aims: Although plant functional traits (PFTs) appear to be important indicators of species' responses to land use changes, there is no clear understanding of how the variations in traits and their plasticity determine variations in species performance. This study investigated the role of functional shoot traits and their plasticity for variation in above-ground net primary productivity (ANPP) due to changes in N supply and in cutting frequency for 13 native perennial C3 grass species. [ABSTRACT FROM PUBLISHER]

Question: Land-use change has a major impact on terrestrial plant communities by affecting fertility and disturbance. We test how particular combinations of plant functional traits can predict species responses to these factors and their abundance in the field by examining whether trade-offs at the trait level (fundamental trade-offs) are linked to trade-offs at the response level (secondary trade-offs). Location: Central French Alps. Methods: We conducted a pot experiment in which we characterized plant trait syndromes by measuring whole plant and leaf traits for six dominant species, originating from contrasting subalpine grassland types. We characterized their response to nutrient availability, shading and clipping. We quantified factors linked with different land usage in the field to test the relevance of our experimental treatments. Results: We showed that land management affected nutrient concentration in soil, light availability and disturbance intensity. We identified particular suites of traits linked to plant stature and leaf structure which were associated with species responses to these environmental factors. Leaf dry matter content separates fast and slow growing species. Height and lateral spread separated tolerant and intolerant species to shade and clipping. Discussion and Conclusion: Two fundamental trade-offs based on stature traits and leaf traits were linked to two secondary trade-offs based on response to fertilization shade and mowing. Based on these trade-offs, we discuss four different species strategies which could explain and predict species distributions and traits syndrome at community scale under different land-uses in subalpine grasslands. [ABSTRACT FROM AUTHOR]

A clear understanding of the feedback between plant communities and soil nutrient cycles is necessary to predict the dynamics of grassland ecosystems. Nitrogen fluxes may depend on specific functional plant traits in relation to dead and living roots, which determine a litter and a rhizosphere effect of the plant community. Two species of nutrient-rich grasslands that demonstrate either a more conservative (Dactylis) or more competitive strategy (Lolium) for nitrogen were grown at a non-optimal level of N availability and at optimal water, P and K supply. In a factorial experiment, monocultures of both species were sown on soil monoliths containing the intact dead root litter system of either species. The N fluxes were measured for two years in these microcosms.The presence of a growing stand increased the N mineralisation rate of the root litter. Both the type of root litter and that of the rhizosphere significantly affected the N fluxes. A greater N harvest was recorded in the Dactylis stand and on the Lolium litter; while greater N loss by leaching occurred under the Lolium stand and from the Lolium litter. Lolium induced a greater N turnover in SOM, while Dactylis caused a faster decay rate of litter N. Dactylis favoured the “short” N cycle between stand and root litter, while Lolium favoured the “complete” N cycle between stand and SOM. The chemical composition of the root litter was similar, but the species effects on the N cycles could be accounted for by differences in morphological root traits. A set of functional root processes is proposed that differentiates species strategies towards the nitrogen cycle. Dynamic consequences for a mixture of the two species are discussed. [Copyright &y& Elsevier]