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Data from: Changes in ecosystem carbon stocks following grazing exclusion in arid and semiarid grasslands

Citation

Yu, Lingfei; Sun, Wenjuan; Huang, Yao (2020), Data from: Changes in ecosystem carbon stocks following grazing exclusion in arid and semiarid grasslands, Dryad, Dataset, https://doi.org/10.5061/dryad.cfxpnvx3h

Abstract

  1. Grazing exclusion (GE) is widely considered to be an important strategy for restoring overgrazed grasslands and promoting carbon (C) storage. However, the changes in the components of ecosystem C with GE and their related drivers remain largely unexplored.
  2. Here, we investigated the effects of GE on the ecosystem C components (plant and soil C) and their key driving factors through sampling inside and outside 15 grazing exclosures across the Inner Mongolia arid and semiarid grasslands in northern China.
  3. Our results showed that, except for dead root C, GE significantly promoted plant C stocks. The increase in AGB and litter C stocks resulted from the accumulation of both biomass and C concentration, while the increase in live root C stock was mainly attributed to biomass accumulation. In contrast, although the topsoil soil C concentration (0-20 cm) showed a marginal increase following GE, its bulk density greatly declined, which resulted in little change in the soil C stocks. Overall, GE had no significant effect on total ecosystem C stocks. Our results further indicated that across the grasslands, GE likely enhanced C accumulation in live roots in humid and fertile sites, while it caused losses of dead root C in relatively humid and fertile sites and increases in arid and infertile sites.
  4. We also found that the increases in AGB C, litter C and live root C stocks were driven by the direct effects of GE and its indirect effects mediated by soil water content. The marginal increases in soil C concentration with GE were linked to only high soil water contents. Meta-analysis further revealed that across the grasslands of China, the responses of ecosystem C components to GE were associated with changes in soil water conditions, suggesting the generality of soil water effects at the national scale.
  5. Overall, our results showed that across arid and semiarid grasslands, GE is generally beneficial for plant C accumulation but has little effect on soil C stocks. Importantly, our study highlighted the important role of soil water in regulating ecosystem C dynamics with GE across the grasslands of China.