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

communications earth & environment Article A Nature Portfolio journal https://doi.org/10.1038/s43247-026-03596-8 Compensatory dynamics among dominant species stabilize plant communities in Tibetan alpine steppes Check for updates 1234567890():,; 1234567890():,; Junfu Dong 1,2 , Lei Zhao 3 , Kai Xue 4,5 4,6 , Zhe Pang , Xiaoyong Cui 7 & Yanfen Wang 4,5 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. Grassland ecosystems, covering about 40% of the Earth’s land surface, serve as an important reservoir of biodiversity and primary productivity to human societies1. In these ecosystems, nitrogen (N) and phosphorus (P) are mostly key nutrients that restrict plant growth and influence community stability2,3, particularly in the most barren regions, such as the Tibetan alpine steppes4. Compared to other ecosystems, this area is one of the most vulnerable and elevated ecosystems in the world, responding to external disturbances quickly5,6. Several lines of evidence indicate that Tibetan alpine steppes are naturally limited in N and P6–8. With the increase of N and P additions from atmospheric deposition and farming practices, the local ecosystems are undergoing remarkable nutrient inputs in this region9–11. The nutrient limitation can then be altered or partially mitigated, but it is imperative to investigate how the plant community stability will change in comparison to its current state. The way that grassland plant communities respond to the addition of N and P varies depending on the species-specific reactions. According to a global study conducted over 45 grasslands, N addition reduced legume cover in nitrogen-deficient soils while boosting non-nitrogenfixing plants. Conversely, P and other nutrients enhanced legume abundance but failed to mitigate the adverse effects of N12. These varied responses to nutrient additions are attributed to plant traits, such as nutrient uptake strategies and competitive abilities, which ultimately impact the plant community stability13,14. Depending on species composition, nutrient additions can either benefit certain plants or lead to their competitive exclusion, thereby modulating its effect on the temporal stability of plant communities15. Such modifications result in changes in community-level attributes, including species richness and evenness, which are pivotal to the stability and function of ecosystems16. Studies showing that N and P additions reduce the stability of grasses-a dominating functional group in many grasslands-underscore the role of plant functional types in mediating these responses13. In particular, N addition increases the inter-annual variation of primary productivity based on 1070 multi-year paired observations, indicating a shift towards species with higher inter-annual variability in abundance. The concomitant reduction in species richness further intensifies this negative impact of nutrient addition on community stability13. Despite these insights, the relationship between species diversity and community stability remains contentious across ecosystems. 1 School of Life Sciences, Shandong University, Qingdao, China. 2Qinghai Provincial Key Laboratory of Cold Regions Restoration Ecology, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China. 3Beijing Key Laboratory of Biodiversity and Organic Farming, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China. 4College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China. 5Beijing Yanshan Earth Critical Zone National Research Station, University of Chinese Academy of Sciences, Beijing, China. 6Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology & Institute of Sanjiangyuan National Park, Chinese Academy of Sciences, e-mail: Xining, China. 7College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China. Communications Earth & Environment | (2026)7:433 1 Article https://doi.org/10.1038/s43247-026-03596-8 Nevertheless, how plant species mediate community stability under nutrient enrichment remains poorly understood. Hautier, Zhang15 bridge this gap, showing that fertilization consistently weakens the stabilizing effect of plant diversity across spatial scales. This occurs because fertilization dampens asynchronous dynamics among species, a key mechanism for stability in diverse plant communities15. Such responses to nutrient additions can lead to shifts in plant community composition, thereby affecting grassland stability. Seabloom, Batzer17 further found that nutrient addition, especially N, reduces local diversity and increases the minimal area of coexistence, indicating changes in the scales at which species interact. Longterm N addition can also alter the β-diversity of plants in a semiarid grassland3, and the above-ground net primary production (ANPP) can be boosted by N and P additions in grasslands but decreased for community stability14. Some studies suggest that this increase in productivity due to nutrient additions can enhance community stability through the portfolio effect18–20. Additionally, long-term warming and N addition can have additive negative effects on community stability21. This suggests that the resistance of grassland communities to N and P additions may be reduced under certain conditions21, underscoring the potential impacts of N and P additions on grassland ecosystems and the complexity of their effects on plant community stability across different environmental contexts. Dominant species also play an important stabilizing role in ecosystems worldwide. Consistent with the mass ratio hypothesis, dominant species exert a larger impact on ecosystem functions and community stability than the non-dominant species22. N and P addit (...truncated)