基于OTCs模拟增温方式探讨气候变暖对青藏高原草地生态系统的影响

开顶式生长室(OTCs)增温实验是研究全球气候变化与陆地生态系统关系的主要方法之一,已广泛应用于青藏高原地区。该文通过对近些年国内外研究文献的回顾,分别从植物物候、群落结构、生物量和土壤方面综合分析青藏高原草地生态系统对OTCs模拟增温实验的响应。研究发现:增温使群落返青期提前、枯黄期延迟,生长季延长;有利于禾本科植物的生长;高寒草甸地下生物量分配格局向深层转移;高寒草地生态系统对模拟增温的响应存在不确定性,受到地域、群落类型和实验时间的影响;在增温条件下,降雨和冻土融化引起的土壤水分变化通过调控生态系统的物候、生产力、土壤等途径控制着生态系统对气候变暖的响应。并在此基础上,提出了将来应着重研究的几个方面。

Effects of global warming on alpine grassland ecosystem on Tibetan Plateau based on OTCs warming experiments

Open-top chambers(OTCs)is one of the main methods to study the relationship between global climate change and terrestrial ecosystem and has been widely used in the Tibetan Plateau. Recent advancements in research on the responses of grassland ecosystems to climate warming by using OTCs are reviewed, which cover the areas of plant phenology, community structure biomass, and soil characteristics. We found that warming extended the growth season was due to advanced the timings of green-up and delayed yellow period. Warming would benefit the growth of gramineous plants. Warming made the biomass allocation transferred to the deeper soil layer to adjust the drying conditions. The response of the alpine grassland ecosystems to climate change was uncertain, which was influenced by region, community type and experimental time. The change of soil moisture caused by rainfall and permafrost melts regulated the response of ecosystem to warming by regulating the temperature sensitivity of phenology, NPP and soil under warming. Based on the discussions, several aspects of future research have been put forward.