Abstract: Exploring the responses of leaf chemical traits and their economics spectrum to environmental changes would help understand plant adaptive strategy from a functional perspective. In this study, responses of plant chemical traits and their correlations at species and communitylevels to different soil water and salinity conditions in the Ebinur Lake Wetland National NatureReserve, northwest of Xinjiang Uygur Autonomous Region were analyzed. The results showed that: (1) With the decreases of soil water and salinity, leaf C content at community level (p_i) significantly decreased (P<0.05), Ca content marginally significantly decreased (P<0.1), leaf S, K, Na and Mg contents significantly increased (P<0.05), and leaf N and P contents showed no significant changes (P>0.05). (2) Alpha trait value (α_i), representing interspecific differences of plants within community, was higher than co-occurred species in the plots with high soil water and salinity, while it was lower than co-occurred species in the plots with low soil water and salinity. The increases of the range ofα_i indicated an intensifying trait divergence with changes of soil water and salinity. (3) Beta trait values (β_i) represented the ecological niche in community trait gradient. β_iof plant N, S, K, Na, Mg in the plots with low soil water and salinity was higher than that in the plots with high soil water and salinity, while C and Ca contents showed the opposite pattern. Suchβ_i differences indicated the significant effects of soil water and salinity on ecological niche of species chemical trait. The range ofβ_i trait became smaller with the decreases of soil water and salinity, indicating the decrease of ecological niche breadth. (4) Trade offs between  light-capture chemistry such as C, N and P and osmotic-metabolic regulation chemistry such as S, K, Ca, Na and Mg were intensified as soil water and salinity decreased. Our results provide theoretical basis for understanding the resource use strategy and adaptation mechanism of desert plants under stress environments.

Key words: Changbai Mountain Natural Reserve, gross primary productivity, VPM model.