Abstract: Understanding ecological implications of plant leaf traits is helpful in exploring community assembly under different environments and thus in revealing the maintenance mechanism of ecosystems. In this study, we measured the stable carbon isotope (¹³C), specific leaf area (SLA), leaf dry matter content (LDMC) and leaf nutrient content of 86 herb species in 25 families along a slope aspect gradient of Southern Gansu alpine meadow, and analyzed correlations between the leaf traits of these plants and environmental factors. The results showed that the soil nutrients and soil water content (SWC) decreased along the northnorthwestwestsouthwestsouth slope aspect gradient, and soil temperature (ST), light illuminance (LI) and pH value increased. Leaf traits also showed strong differences at different slopes. LWC, LPC, SLA, LKC decreased significantly, and LDMC, SPAD and ¹³C values increased significantly along the slope aspect gradient. RDA results showed that LWC, LPC, SLA and LKC were positively correlated with the SWC, soil organic carbon (SOC), total phosphorus (TP), available phosphorus (AP), but negatively correlated with the ¹³C, LDMC and SPAD. Relationships between ST, LI, pH and leaf traits showed the opposite trend, and the contributions of different environmental factors to leaf traits were different. The SWC, TP, ST and pH value were the key limiting factors. The patterns of responses of leaf traits to environmental factors under the conditions of different slope aspects reflect the environmentsl condition and stability of alpine meadow ecosystems.

Key words: farmland soil, mining area, mercury, Tongling