Nitrogen and Phosphorus Stoichiometry and Resorption Characteristics of Dominant Trees in the Primary Succession Sequence of Hailuogou Glacier Retreat Area, Tibetan Plateau, China

Based on the primary succession of vegetation in the Hailuogou glacier retreat area, the characteristics of nitrogen(N) and phosphorus(P) stoichiometry and resorption efficiency of dominant trees in different succession stages were studied. The results showed that the N and P concentrations of fresh leaves and litters decreased with succession, and the N∶P of fresh leaves were less than 14 in the whole succession sequence, indicating that the growth of dominant trees in this succession sequence was mainly limited by N; the N and P resorption efficiency of dominant trees was the highest in the middle succession stage, indicating that higher plant growth rate would increase the efficiency of nutrient uptake and utilization; the resorption efficiency of N and P were positively correlated with their growth rate, and negatively correlated with soil N and P storage, indicating that the tree growth rate(demand) and soil nutrient status(supply) jointly regulated the nutrient uptake pattern of vegetation, the N resorption efficiency of dominant trees was positively correlated with the N∶P, indicating that the N resorption process of vegetation was important to maintain the balance of the N∶P. These results are helpful to deeply understand the nutrient utilization mechanism of vegetation in the process of primary succession, and provide theoretical basis for vegetation restoration.