Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species‐level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1–315%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species’ populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.

Biodiversity generally promotes ecosystem stability. To assess whether the diversity–stability relationship observed under ambient nitrogen (N) conditions still holds under N enriched conditions, we designed a 6‐year field experiment to test whether the magnitude and frequency of N enrichment affects ecosystem stability and its relationship with species diversity in a temperate grassland. Results of this experiment showed that the frequency of N addition had no effect on either the temporal stability of ecosystem and population or the relationship between diversity and stability. Nitrogen addition decreased ecosystem stability significantly through decreases in species asynchrony and population stability. Species richness was positively associated with ecosystem stability, but no significant relationship between diversity and the residuals of ecosystem stability was detected after controlling for the effects of the magnitude of N addition, suggesting collinearity between the effects of N addition and species richness on ecosystem stability, with the former prevailing over the latter. Both population stability and the residuals of population stability after controlling for the effects of the magnitude of N addition were positively associated with ecosystem stability, indicating that the stabilizing effects of component populations were still present after N enrichment. Our study supports the theory predicting that the effects of environmental factors on ecosystem functioning are stronger than those of biodiversity. Understanding such mechanisms is important and urgent to protect biodiversity in mediating ecosystem functioning and services in the face of global changes.

Phosphorus (P) limitation is expected to increase due to nitrogen (N)‐induced terrestrial eutrophication, although most soils contain large P pools immobilized in minerals (P_i) and organic matter (P_o). Here we assessed whether transformations of these P pools could increase plant available pools alleviating P limitation under enhanced N availability. The mechanisms underlying these possible transformations were explored by combining results from a 10‐year field N addition experiment and a 3700‐km transect covering wide ranges in soil pH, soil N, aridity, leaching, and weathering that could affect soil P status in grasslands. Nitrogen addition promoted the dissolution of immobile P_i (mainly Ca‐bound recalcitrant P) to more available forms of P_i (including Al‐ and Fe‐bound P fractions and Olsen P) by decreasing soil pH from 7.6 to 4.7, but did not affect P_o. Soil total P declined by 10% from 385 ± 6.8 to 346 ± 9.5 mg kg⁻¹, whereas available P increased by 546% from 3.5 ± 0.3 to 22.6 ± 2.4 mg kg⁻¹ after the 10‐year N addition, associated with an increase in P_i mobilization, plant uptake, and leaching. Similar to the N addition experiment, the drop in soil pH from 7.5 to 5.6 and increase in soil N concentration along the grassland transect were associated with an increased ratio between relatively mobile P_i and immobile P_i. Our results provide a new mechanistic understanding of the important role of soil P_i mobilization in maintaining plant P supply and accelerating biogeochemical P cycles under anthropogenic N enrichment. This mobilization process temporarily buffers ecosystem P limitation or even causes P eutrophication, but will extensively deplete soil P pools in the long run.