No abstract

Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 107 and 6.15 × 107 Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist.

No abstract

Embraced for decision-making, resilience has evolved as a meaningful term in areas such as ecology, the economy and society. After a policy of grassland contracts was implemented on the Qinghai-Tibetan Plateau, two grassland management patterns evolved: the multi-household management pattern (MMP) and the singlehousehold management pattern (SMP). Within a resilience-driven perspective, this study compared the outcomes of these grassland management patterns by measuring their effects on the resilience of grazing, ecological, economic and social systems. Resilience indicators for each of the four systems were: grazing system (grazing space, transhumance, water source and reproduction); ecological system (vegetation including cover, biomass, species richness and soil properties including pH, organic carbon, total nitrogen and total phosphorus); economic system (income, expenditure and infrastructure) and the social system (health, assistance, social relations, cultural inheritance and institutional arrangements). In order to provide a social-ecological resilience framework for the two grassland management patterns, a decision support tool was applied to approximately gauge the resilience of each indicator. The results showed that each of the four systems under the MMP had a greater degree of resilience than the SMP, and that the overall resilience of the MMP was estimated at 5.8 units compared to about −5.8 units for the SMP. The relative success of the MMP was seen to rest largely on the maintenance of traditional management practices, social networks, trust and the low cost and high efficiency of informal institutions, which acted to reduce the risk of unsustainable development of ecological and social systems. The important take-home lesson from this study is that contracting of grasslands to private entities on the Qinghai-Tibetan Plateau, and in the rest of the world where similar land management practices exist, must be undertaken with caution.

Accounting for one quarter of China's land area, the endorheic Shiyang River basin is a vast semi-arid to arid region in China's northwest. Exploring the impact of changes in land use on this arid area's carbon budget under global warming is a key component to global climate change research. Variation in the region's soil carbon storage due to land use changes occurring between 1973 and 2012 was estimated. The results show that land use change has a significant impact on the soil carbon budget, with soil carbon storage having decreased by 3.89 Tg between 1973 and 2012. Grassland stored the greatest amount of soil carbon (114.34 Mg ha −1 ), whereas considerably lower carbon storage occurred in woodland (58.53 Mg ha −1 ), cropland (26.75 Mg ha −1 ) and unused land (13.47 Mg ha −1 ). Grasslands transformed into cropland, and woodlands degraded into grassland have substantially reduced soil carbon storage, suggesting that measures should be adopted to reverse this trend to improve soil productivity.