Drought timing and primary productivity in a semiarid grassland.
Drought timing and primary productivity in a semiarid grassland.
复制标题
半干旱草原的干旱时间和初级生产力。
DOI：
10.1002/ldr.3603
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发表时间：
--
影响因子：
4.7
通讯作者：
Zhongling Yang
中科院分区：
文献类型：
--
作者：
Jiajia Zhang;Yuan Miao;Tong Zhang;Yueyue Wei;Xiaoxin Qiao;Renhui Miao;Dong Wang;Shijie Han;Zhongling Yang
虽然大多数研究都考虑了年总降水量对地上净初级生产力(ANPP)的影响，但很少有研究表明特定生长季节降水减少对ANPP有何影响。通过降水模拟试验，研究了中国北部温带草原早季和晚季降水减少的响应模式及其机制。结果表明，地塞米松和丹参多糖均可使心钠素 m−-2平均降低28.3g和39.4g。多年生草本植物 m−2减少2 0.7g，亚灌木减少4.9g m−2，多年生杂草减少36.6g m−2，亚灌木减少8.7g m−2。而多年生杂草ANPP的降低主要是由于生长后期土壤水分的降低所致。DEP和DLP下亚灌木ANPP的下降可以用DEP下亚灌木的浅根长和DLP下较高的土壤温度来解释。我们的研究结果表明，干旱时机如何在社区和功能群体水平上影响ANPP。不同功能基团对干旱时序的不同响应表明，未来的研究不应忽视降水时序在调节生态系统生产力中的作用。
While most studies account for the effect of total annual precipitation on aboveground net primary production (ANPP), few studies have demonstrated how decreased precipitation within specific periods of growing season affects ANPP. Using a precipitation manipulation experiment, we assessed the response patterns and underlying mechanisms of ANPP to decreased precipitation in the early (DEP) and late (DLP) growing seasons on a temperate steppe in northern China. The results showed that both DEP and DLP decreased ANPP by averages of 28.3 and 39.4 g m−2, respectively. The decline of ANPP in DEP was primarily attributed to a 20.7 g m−2 decrease in grass and 4.9 g m−2 decrease in sub‐shrubs, whereas the decrease in ANPP in DLP was due to a 36.6 g m−2 decrease in perennial forbs and an 8.7 g m−2 decrease in sub‐shrubs. The reduction in grass ANPP under DEP was likely due to decreased soil moisture and increased specific leaf area of grass during the early growing season, whereas the reduction in perennial forbs ANPP under DLP was mainly caused by decreased soil moisture during late growing season. The decline of sub‐shrubs ANPP under DEP and DLP could be explained by shallow root length of sub‐shrubs in DEP and by high soil temperature in DLP. Our findings demonstrated how droughts timing affects ANPP at both community and functional group levels. Different responses of functional groups to drought timing indicate that future studies should not neglect the role of precipitation timing in regulating ecosystem productivity.