Abstract: The effects of nutrient and water additions on nitrogen utilization rate of alpine plants were investigated using the ¹⁵N labeling technique in a Kobresia humilis meadow over a short term period. Four treatments were set up as follows: increased snow in winter (W), N fertilization (N), P fertilization (P), and control (CK). About one month after the labeling, the ¹⁵N absolute abundance of belowground of plants was the highest. More added N was recovered in the soil. This indicates that N was not fully used by plants in the short term, and less N was transferred into litter. The N utilization rates for plants under different treatments were in order of P treatments > N treatments > W treatments > CK. This reflects that nutrient and moisture modify N utilization rate of alpine plants in K. humilis meadows, and the nutrient is more important.

Key words: ecological source, geological disaster sensitivity, ecological importance, ecological corridor, ecological security pattern