Chen Yanfeng, Zhang Hui, Zhang Lingwei, Zhang Lan, Cao Qiumei, Liu Huiliang, Zhang Daoyuan
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
Department of Tourism Management, School of Geography and Tourism, Qufu Normal University, Rizhao 276826, China.
Plants (Basel). 2021 Aug 10;10(8):1642. doi: 10.3390/plants10081642.
Future climate is projected to increase in the intensity and frequency of extreme precipitation events, and the resulting ecological consequences are often more serious than those of normal precipitation events. In particular, in desert ecosystems, due to the low frequency and strong fluctuation of extreme precipitation, the destructive consequences for desert plants caused by extreme precipitation have not received enough attention for some time. Based on statistics of extreme precipitation events (1965-2018) in the Gurbantunggut Desert, we investigated the effects of extreme precipitation (+0%, CK; +50%, W1; +100%, W2; +200%, W3; maintenance of field capacity, W4) on the plant life-history of the spring-germinated (SG) and autumn-germinated (AG) ephemeral plant by monitoring seedling emergence, survival, phenology, organ size, biomass accumulation, and allocation. The results showed that extreme precipitation caused about 2.5% seedling emergence of in autumn 2018 and 3.0% seedling emergence in early spring 2019, which means that most seeds may be stored in the soil or have died. Meanwhile, extreme precipitation significantly improved the survival, organ size, and biomass accumulation of SG and AG plants, and W3 was close to the precipitation threshold of SG (326.70 mm) and AG (560.10 mm) plants corresponding to the maximum individual biomass; thus, AG plants with a longer life cycle need more water for growth. Conversely, W4 caused AG plants to enter the leaf stage in advance and led to death in winter, which indicates that extreme precipitation may not be good for AG plants. Root and reproduction biomass allocation of SG and AG plants showed a significantly opposite trend under extreme precipitation treatments, which might be related to their different life-history strategies. Therefore, when only taking into account the changing trend of extreme precipitation from the Coupled Model Intercomparison Project 6 (CMIP6) climate projections data, we speculate that extreme precipitation may promote the growth of SG and AG plants from the beginning to the middle of this century, but extreme precipitation in autumn exceeding a certain threshold may adversely affect the survival of AG plants at the end of the century.
预计未来气候将使极端降水事件的强度和频率增加，其产生的生态后果往往比正常降水事件更为严重。特别是在沙漠生态系统中，由于极端降水的频率较低且波动较大，一段时间以来，极端降水对沙漠植物造成的破坏后果尚未得到足够关注。基于对古尔班通古特沙漠极端降水事件（1965 - 2018年）的统计，我们通过监测幼苗出土、存活、物候、器官大小、生物量积累和分配情况，研究了极端降水（+0%，CK；+50%，W1；+100%，W2；+200%，W3；田间持水量，W4）对春季萌发（SG）和秋季萌发（AG）的一年生短命植物生活史的影响。结果表明，极端降水导致2018年秋季约2.5%的种子出土，2019年早春3.0%的种子出土，这意味着大多数种子可能储存在土壤中或已经死亡。同时，极端降水显著提高了SG和AG植物的存活率、器官大小和生物量积累，且W3接近SG（326.70毫米）和AG（560.10毫米）植物对应最大个体生物量的降水阈值；因此，生命周期较长的AG植物生长需要更多水分。相反，W4使AG植物提前进入叶片阶段并导致冬季死亡，这表明极端降水可能对AG植物不利。在极端降水处理下，SG和AG植物的根生物量分配和繁殖生物量分配呈现出显著相反的趋势，这可能与其不同的生活史策略有关。因此，仅考虑来自耦合模式比较计划第6阶段（CMIP6）气候预测数据中极端降水的变化趋势，我们推测极端降水在本世纪中叶之前可能促进SG和AG植物的生长，但秋季极端降水超过一定阈值可能在本世纪末对AG植物的存活产生不利影响。
