Leaf functional traits of dominant desert plants in the Hexi Corridor, Northwestern China: Trade-off relationships and adversity strategies

Desert plants are zonal vegetation with unique functional traits and resource trade-offs in arid areas. The trade-off relationship among functional traits and adversity strategies of desert plants play a key role in their community construction. We investigated 16 leaf functional traits of the dominant desert plants, including15 shrubs and 11 herbs, in the Hexi Corridor from southeast to northwest, and analyzed the variation characteristics of traits, trade-off relationship among traits and their responses to soil properties at the regional scale. The results showed that bound water (BW), leaf thickness (LT), and carbon phosphorus ratio (C:P) but total water content (TWC), free water (FW), specific leaf volume (SLV), and specific leaf area (SLA) under shrubs were significantly higher and significantly lower than under herbs, respectively; shrubs' leaf traits BW and FW ratio (BW:FW), phosphorus content (P), C:P, nitrogen and phosphorus ratio (N:P) had great coefficient of variation, while herbs' leaf traits BW and N:P had great coefficient of variation. Trade-off among the measured traits was diverse. The TWC, BW, SLV, leaf succulence (Suc), SLA, leaf dry matter content (LDMC) and LT are prominent traits that represent and reflect desert plants under adversity stress. Soil organic carbon (SOC), elevation, pH, soil water content (SW) and sand (0.5-0.25 mm) are important factors influencing the changes of shrubs' leaf traits, while available phosphorus (AP), SOC, silt (0.02-0.002 mm), sand (0.10-0.05 mm) and clay (<0.002 mm) are dominant factors affecting the changes of herbs' leaf traits. The results from the present study can provide theoretical support for the maintenance, management and stability of the Hexi Corridor' ecosystems.