The Variations In Plant Functional Traits And Forest Carbon Content With Altitudinal Gradients In The Tianshan Mountains

Plant functional traits are important characteristics for understanding the relationship between individual,community,and ecosystem functions.In recent years it has been widely applied to explore the mechanism between community construction and the process,function of ecosystem.Previous studies focused on analysing the change of plant functional traits along the environmental gradients in individual scales,but these does not reflect the plant ecology construction mechanism to acclimatized the environmental gradient through the community,it was difficult to established contact with physiological ecology of plant functional traits and ecosystem function community.Therefore,there are still many issues about how to build communities on the environmental gradient through continuous changes of plant functional traits and how plant function traits reflect ecosystem functions.There were three questions has been solved by 14 indexes which collected to estimated the carbon density of each component of the community included tree layer,shrub layer and herb layer samples respectively in Tianshan mountain.?1?to investigate whether altitudinal gradient in community construction represented by the continuous variation of plant functional traits?2?community scale plant functional traits variation with altitude?3?contact mechanism of community carbon density and plant functional traits.The results shows that:?1?From the perspective of functional form,5 traits(leaf carbon content(C_leaf),leaf dry matter content?LDMC?,fine root carbon content(C_root),leaf lignin content?LLC?,plant height?H?)showed arbors>shrubs>herbs,5 traits?leaf nitrogen content?Nleaf?,leaf N:P ratio?N/P?,chlorophyll content?Chl?,fine root nitrogen content?Nroot?,fine root phosphorus content?Proot??showed herbs>shrubs>arbors.2 traits?leaf C:No?C/N?,fine root dry matter content?RDMC??showed similar characteristic of shrubs and trees and not significantly greater than the herb,2 traits?leaf P content?Pleaf?specific root length?SRL??had no significant difference.?2?As a result of the multiple filtration by different factors such as climate,soil and interspecific interaction on the altitudinal gradient,the variation patterns of different functional species with altitude are quite different,and most of them are linear and polynomial distribution,resulting in the differentiation of community structure on altitude gradient.?3?it shows that at a higher altitude,the carbon to nitrogen ratio?C/N?in leaves increased linearly,whereas carbon content(C_leaf),specific root length?SRL?,and height?H?initially increased and then decreased.Chlorophyll content?Chl?and fine root phosphorus content(P_root)decreased with elevation and fine root carbon content(C_root)initially increased and then flattened out with altitude.Fine root nitrogen content(N_root)initially decreased and then increased,whereas leaf nitrogen content(N_leaf),lignin content?LLC?,and fine root dry matter content?RDMC?showed no significant difference with altitude.Nleaf,LLC,LDMC,RDMC in each elevation segment had no significant difference;?4?the altitude gradient H community were significantly affected by soil organic matter and moisture index.The content and ratio of nutrient elements were influenced by the content of these elements in soil,LDMC and RDMC were significantly related to community and hydrothermal conditions,community SRL and Chl mainly influenced by temperature control,and the precipitation influence communities LLC directly.?5?SRL,H,the content of C,P in leaf and root showed significant correlations with vegetation carbon density?VCD?and soil carbon density?SCD?in the Tianshan forest,as they have influential effects on the photosynthesis of vegetation,in which SRL and H could affect plants resource acquisition and utilization,whereas C and P would limit nutrient availability.There was a negative correlation between LLC and SCD in the Tianshan forest,as LLC would limit the decomposition rate of plant residue.VCD initially increased and then decreased,whereas SCD and total carbon density?TCD?increased gradually with altitude.?6?it shows that the relationship between VCD and community H,N/P,TCD and C_leaf,and the community SRL changed significantly along the altitudinal gradient.The relationship between components of carbon density and functional traits in altitude showed convergence,but effected of change slightly about the pressure of selection and the individual traits,carbon density and community characters showed significant correlation only in the corresponding segment elevation.It defines the altitude gradient between different plant functional types and different traits along altitudinal gradient variation in this paper.analysis,the plant functional traits on the community scale the vertical band spectrum and the influence factors by the altitude gradient,discusses the connection between the mechanism of community carbon density and the plant functional traits,toprovide valuable basic data for the conservation,management and operation of Tianshan mountain forest,and the forest management and the function of under the background of global change prediction basis.