Plant Functional Traits Of Terperate Shrubs In Inner Mongolia

Plant functional traits are the adaptation strategies of plants to environmental changes in the long evolution process and the representation of trade-off between different internal functions.The study of functional traits for various plant species and their response to environmental factors is helpful to understand the plant strategies and predict the consequence of climate change on ecosystem functions.Many studies have examined the variability of traits for various plant species and find both environment and phylogenetic exert strong impacts on plant traits.However,previous studies commonly concern on herbs,trees or the combination of multiple lifestyles(i.e.,trees,herbs and shrubs),shrub plants have seldom been reported in previous studies.Shrub species widely distributed across desert,grassland and mountain areas along the aridity gradients in Inner Mongolia,providing the opportunity to examine the variability corresponds to the variations in environmental factors.We conducted a field investigation at 155 sites dominated by shrub plants in Inner Mongolia.Totally 67 dominant shrub species were sampled and 10 functional traits were measured,including plant height(H),width of clump crown(WCC),leaf area(LA),leaf thickness(LT),stem tissue density(STD),leaf dry matter content(LDMC),specific leaf area(SLA),leaf carbon content(LC),leaf nitrogen content(LN)and leaf carbon to nitrogen ratio(C:N).We compared the difference for these functional traits for species distributed in desert,grassland and open mountain areas.Further,we analyzed the trade-off relationships between functional traits,and(1)the species levels,where the functional traits of species sampled at different sites along environmental gradients;(2)the intra-specific level,where the variability of plant traits in response to environmental factors is tested within a single species(i.e.,Ostryopsis davidiana);and(3)the genus level,where the variability of plant traits in response to environmental factors is tested within a genus(Caragana).The results showed that most plant functional traits measured here varied considerably among species,with the exception of leaf carbon content having minimal variations at inter-species and intra-specific levels.The values of H,LA,SLA and C:N for mountain shrubs were generally higher than those of shrubs in desert and grassland areas,while WCC and LN for grassland shrubs were significantly higher than that of shrubs grow in desert and mountain regions.Moreover,the shrubs in arid deserts commonly form the large woody density and leaf thickness but low LDMC,SLA and LN in fitting to the arid environment.We found the widespread trade-off relationships between plant traits either for data pooled for all species or the data for species in different ecosystems.The phylogenetic and environmental factors have strong effects on plant traits,especially for plant height and leaf traits.Furthermore,the variability of traits within a species or within a genus reflects the capacity of a species in response to environmental factors.In this study,the suit of traits of for Ostryopsis davidiana and Caragana spp.remain responded significantly to variations in environment factors.The above-mentioned results reflect that the traits of leaves and stems for shrubs respond strongly to environment factors,especially to climate factors.Under different environments,shrubs develop a suit of varied traits.Moreover,the phylogenetic effects also play an important role in the functional traits of these plants.