Lv Xiaomin, He Qijin, Zhou Guangsheng
State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing China.
College of Resources and Environmental Sciences China Agricultural University Beijing China.
Ecol Evol. 2019 Jul 15;9(16):9061-9075. doi: 10.1002/ece3.5452. eCollection 2019 Aug.
Climate change, characterized by warming and precipitation variability, restricted the growth of plants in arid and semiarid areas, and various functional traits are impacted differently. Comparing responses of functional traits to warming and precipitation variability and determining critical water threshold of dominate steppe grasses from Inner Mongolia facilitates the identification and monitoring of water stress effects. A combination of warming (ambient temperature, +1.5°C and +2.0°C) and varying precipitation (-30%, -15%, ambient, +15%, and +30%) manipulation experiments were performed on four species (, , , and ) from Inner Mongolia steppe. The results showed that the functional traits of the four grasses differed in their responses to precipitation, but they shared common sensitive traits (root/shoot ratio, R/S, and specific leaf area; SLA) under ambient temperature condition. Warming increased the response of the four grasses to changing precipitation, and these differences in functional traits resulted in changes to their total biomass, with leaf area, SLA, and R/S making the largest contributions. Critical water thresholds of the four grasses were identified, and warming led to their higher optimum precipitation requirements. The four steppe grasses were able to adapt better to mild drought (summer precipitation decreased by 12%-28%) when warming 1.5°C rather than 2.0°C. These results indicated that if the Paris Agreement to limit global warming to 1.5°C will be accomplished, this will increase the probability for sustained viability of the steppes in the next 50-100 years.
气候变化以变暖和降水变率为特征，限制了干旱和半干旱地区植物的生长，且各种功能性状受到的影响各不相同。比较功能性状对变暖和降水变率的响应，并确定内蒙古典型草原优势禾本科植物的临界水分阈值，有助于识别和监测水分胁迫效应。对内蒙古草原的四个物种（、、和）进行了增温（环境温度、+1.5°C和+2.0°C）和不同降水（-30%、-15%、环境、+15%和+30%）控制实验的组合。结果表明，这四种禾本科植物的功能性状对降水的响应不同，但在环境温度条件下它们具有共同的敏感性状（根冠比，R/S，和比叶面积；SLA）。增温增加了这四种禾本科植物对降水变化的响应，这些功能性状的差异导致了它们总生物量的变化，其中叶面积、SLA和R/S的贡献最大。确定了这四种禾本科植物的临界水分阈值，增温导致它们对最佳降水量的需求更高。当增温1.5°C而非2.0°C时，这四种草原禾本科植物能够更好地适应轻度干旱（夏季降水量减少12%-28%）。这些结果表明，如果将全球变暖限制在1.5°C的《巴黎协定》能够实现，这将增加未来50-100年内草原持续生存的可能性。
