Variation in Community Leaf Stoichiometry and Nutrient Resorption Along an Elevational Gradient on the Northern Slope of the Kunlun Mountains.

Leaf stoichiometry and nutrient resorption are key indicators for assessing nutrient-use status and predicting nutrient limitation in plant growth. However, the patterns of variation in plant community nutrient-use traits along elevational gradients remain unclear. To address this, we measured leaf nutrient contents of plant communities across six elevational gradients (1960 to 3548 m) on the northern slope of the Kunlun Mountains. We systematically analyzed variations in leaf stoichiometric traits, nutrient homeostasis, and nutrient resorption efficiency (NuRE), with a particular focus on the control strategies of nutrient resorption and their responses to environmental variables. The results showed that plant communities across all elevations in the study area exhibited co-limitation by nitrogen (N) and phosphorus (P). NuRE and PRE were higher than the global average, indicating that in nutrient-poor environments, plants adopt adaptive strategies by enhancing nutrient resorption to reduce nutrient loss. Both NuRE and PRE declined significantly at high elevations (3248-3548 m), while the NuRE:PRE ratio tended to stabilize, suggesting a reduced dependence on nutrient resorption and a more balanced N and P availability in soils at higher altitudes. NuRE was mainly regulated by plant community diversity, whereas PRE was primarily driven by climatic factors. Under the nutrient-poor conditions of the study area, plant communities tended to adopt stoichiometric control strategies to optimize nutrient resorption, thereby enhancing the efficiency of energy and resource allocation. Furthermore, we propose that the combined use of NuRE:PRE and LTN:LTP serves as a more robust framework for assessing nutrient limitation. This study improves our understanding of the patterns of nutrient limitation and nutrient resorption processes along elevational gradients in arid mountain regions and provides new insights into nutrient regulation mechanisms underlying plant adaptation to environmental heterogeneity.