Compensatory dynamics among dominant species stabilize plant communities in Tibetan alpine steppes

Plant community stability is often hindered by nitrogen and phosphorus deficiencies in high-altitude alpine steppes. While nutrient addition can mitigate these constraints, the individual and interactive effects of these elements to community stability remain unclear. Here we elucidated the underlying mechanisms by decomposing asynchrony into compensatory and statistical-averaging effects across undegraded and degraded grasslands on the Tibetan Plateau, under conditions with and without nitrogen and phosphorus additions. In undegraded alpine steppes, phosphorus limits plant coverage, while nitrogen joins as a limiting factor under degradation. Phosphorus addition threatens stability in pristine areas, whereas nitrogen enhances degraded steppes’ biodiversity and statistical-averaging effects. Despite varying nutrient scenarios, the compensatory effects among dominant species persist, primarily regulating community stability, rather than population stability or statistical-averaging effects. These results underscore the pivotal role of dominant species in community stability and their diverse compensatory dynamics in undegraded and degraded steppes under nutrient addition conditions. Community stability in alpine steppes is governed mainly by compensatory dynamics among dominant species, with phosphorus destabilizing undegraded systems and nitrogen improving stability in degraded grasslands, based on nutrient addition experiments across Tibetan Plateau steppes