Biomass temporal stability increases at two spatial scales during secondary succession

1. Ecological stability has long been considered to change over succession, but how secondary succession influences the relationship between diversity and temporal stability of biomass production at different spatial scales is poorly understood.2. We studied changes in plant diversity, functional temporal stability (biomass production) and compositional temporal stability (the latter two are hereafter referred to as functional stability and compositional stability) and explored the stabilizing roles of plant diversity at two spatial scales (small plots of 0.25 m(2) and large transects of 1.25 m(2)) during secondary succession in a subalpine meadow from 2003 to 2010.3. Our results showed that both plant diversity and functional and compositional stability increased at the small plot scale and large transect scale during secondary succession. As secondary succession proceeded, higher average alpha diversity (i.e. species diversity at the plot scale) led to higher functional and compositional stability at the plot scale by mainly species stability, predominantly contributing to higher functional and compositional stability at the large transect scale. In addition, Simpson- based beta diversity (i.e. compositional dissimilarity among communities within the same transect), while unaffected by succession, contributed to functional stability at the large transect scale by promoting asynchronous dynamics among communities.4. Synthesis. Our study highlights the stabilizing effects of plant diversity across the two spatial scales during secondary succession. Our findings provide the first empirical evidence that biodiversity-mediated effects on ecosystem temporal stability strengthen over successional time, suggesting that the stabilizing effects of biodiversity should be considered across spatial and temporal scales in the face of global changes and biodiversity loss.