Responses of typical grasslands in a semi-arid basin on the Qinghai-Tibetan Plateau to climate change and disturbances

Alpine grassland ecosystems on the Qinghai-Tibetan Plateau (QTP) are vulnerable to climate change and anthropogenic disturbances, which may have significant effects on the QTP's carbon budgets. In this study, vegetation and soil characteristics were compared among alpine grassland ecosystems in a semi-arid basin on the northeast ridge of the QTP (1) among alpine swamp meadow, meadow, steppe meadow and steppe soils, which represent the direction of succession under climate-warming conditions, and (2) among alpine, degraded and tilled meadow soils to investigate the effects of human disturbance. The results showed that (1) if the alpine grassland ecosystems succeed in this direction, climate warming will cause a loss of carbon, and (2) tilling activity also results in carbon loss. Therefore, these results indicate that anthropogenic disturbance regimes that change more rapidly than climate may exert a more profound influence on carbon dynamics and balance. However, the plots that were set in the present study represented only part of the basin due to road accessibility. Relationships between leaf area index (biomass and soil carbon) and fractional vegetation cover x vegetation height from this study are fairly good, which can be applied at regional scale to estimate carbon pools. In combination with detailed information of grassland types, climate and human activities, the effects of climate change and disturbances can be estimated using remote sensing datasets.