title: Plant functional trait diversity regulates the nonlinear response of productivity to regional climate change in Tibetan alpine grasslands.
abstract: The biodiversity-productivity relationship is still under debate for alpine grasslands on the Tibetan Plateau. We know little about direct and indirect effects of biotic and abiotic drivers on this relationship, especially in regard to plant functional trait diversity. Here, we examine how aboveground net primary productivity (ANPP) and precipitation use efficiency (PUE) respond to climate, soil and community structure across alpine grasslands on the Northern Tibetan Plateau. We found that both ANPP and PUE showed nonlinear patterns along water availability and site altitude variation, which together accounted for 80.3% and 68.8% of variation in ANPP and PUE, respectively, by optimal generalized additive models. Functional trait divergence (FTD) and community weighted mean (CWM) of plant functional traits were as important as plant species diversity (PSD) for explaining the nonlinear productivity-climate relationship. These findings were confirmed by results from principal component analyses and structural equation models. We also found that FTD was negatively correlated with PSD across different alpine grasslands. Our results implicate: first, the combinatorial influences of temperature and precipitation gradients are important for predicting alpine grassland dynamics; second, the convergence and divergence of plant functional traits may have the potential to elucidate the effect of plant diversity on ecosystem functionality.
authors.affiliation: Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing, China.|Functional Biodiversity, Dahlem Center of Plant Sciences, Free University of Berlin, 14195 Berlin, Germany.
authors.forename: Jianshuang
authors.initials: J
authors.lastname: Wu
authors.affiliation: Functional Biodiversity, Dahlem Center of Plant Sciences, Free University of Berlin, 14195 Berlin, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Wurst
authors.affiliation: Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing, China.
authors.forename: Xianzhou
authors.initials: X
authors.lastname: Zhang
mesh_terms: D044822:Biodiversity; D000073537:Biological Variation, Population; D057231:Climate Change; D017753:Ecosystem; D065948:Grassland; D063245:Plant Development; D011891:Rain; D012987:Soil / Q000737:chemistry; D018609:Tibet
chemical_list: D012987:Soil