Temperature mediated responses of carbon fluxes to precipitation variabilities in an alpine meadow ecosystem on the Tibetan Plateau

Effects of climate warming and changing precipitation on ecosystem carbon fluxes have been intensively studied. However, how they co-regulate carbon fluxes is still elusive for some under-studied ecosystems. To fill the gap, we examined net ecosystem productivity (NEP), gross ecosystem productivity (GEP) and ecosystem respiration (ER) responses to multi-level of temperature increments (control, warming 1, warming 2, warming 3, warming 4) in three contrasting hydrological growing seasons in a typical semiarid alpine meadow. We found that carbon fluxes responded to precipitation variations more strongly in low-level warming treatments than in high-level ones. The distinct responses were attributable to different soil water conditions and community composition under low-level and high-level warming during the three growing seasons. In addition, carbon fluxes were much more sensitive to decreased than to increased precipitation in low-level warming treatments, but not in high-level ones. At...

气候变暖与降水变化对生态系统碳通量的影响已得到广泛研究。然而，对于部分研究不足的生态系统而言，二者如何协同调控碳通量仍不明确。为填补这一空白，我们在典型半干旱高寒草甸的三个水文条件差异显著的生长季中，研究了净生态系统生产力（NEP）、总生态系统生产力（GEP）和生态系统呼吸（ER）对多水平温度升高（对照、升温1、升温2、升温3、升温4）的响应。研究发现，在低水平升温处理中，碳通量对降水变化的响应比高水平升温处理更为强烈。这种显著差异归因于三个生长季内低水平与高水平升温下不同的土壤水分条件及群落组成。此外，在低水平升温处理中，碳通量对降水减少的敏感性显著高于对降水增加的敏感性，而高水平升温处理中无此差异。在...