Han Chunxue, Li Ruichao, Li Haigang
College of Resources and Environmental Sciences, Inner Mongolia Agricultural University, Hohhot, China.
Inner Mongolia Key Laboratory of Soil Quality and Nutrient Resource, Hohhot, China.
PLoS One. 2024 Dec 16;19(12):e0314983. doi: 10.1371/journal.pone.0314983. eCollection 2024.
Precipitation distribution during the growing season and interannual precipitation variation may have significant impacts on grassland ecosystem productivity at the site level. To explore the effect of the distribution of precipitation on plant communities in the Inner Mongolian desert steppe dominated by Stipa breviflora, we analyzed monthly precipitation patterns during the growing season (May-October) over the past 60 years (1961-2020) and identified four major precipitation distribution patterns. These included the concentrated precipitation during July (TΛ7), August (TΛ8), and during the early and late growth stages. However, with precipitation being scarce during the boom (TM), the distribution resembled a normal distribution (T∩). Field experiments simulating the four distributions were conducted from May to October 2021. The results showed that the effects of the distribution of precipitation on plant species, diversity, and abundance were not significant; only the Pielou evenness showed a significant effect after July. The total above-ground net primary productivity (ANPP) of TΛ7 was 55.4% higher than those of the other three patterns, whereas the differences among the other three precipitation distributions were not significant. The annual forb Neopallasia pectinate was the primary contributor to the increased ANPP of TΛ7. These results suggest that the S. breviflora desert steppe achieved maximum productivity when the precipitation reached 41.6% of the annual average during July and satisfied the basic plant growth requirements during other months. This study emphasizes the implementation of management measures (irrigation or artificial precipitation) for maximizing forage yield and forecasting the plant composition in desert steppes.
生长季内的降水分布以及年际降水变化可能会对局部尺度的草地生态系统生产力产生重大影响。为了探究降水分布对以内蒙古短花针茅荒漠草原为主的植物群落的影响，我们分析了过去60年（1961—2020年）生长季（5—10月）的月降水模式，并确定了四种主要降水分布模式。这些模式包括7月（TΛ7）、8月（TΛ8）的集中降水，以及生长前期和后期的降水。然而，在生长旺盛期（TM）降水稀少，其分布类似正态分布（T∩）。于2021年5—10月开展了模拟这四种分布的田间试验。结果表明，降水分布对植物物种、多样性和丰富度的影响不显著；仅在7月之后皮洛均匀度显示出显著影响。TΛ7的地上总净初级生产力（ANPP）比其他三种模式高55.4%，而其他三种降水分布模式之间的差异不显著。一年生草本栉叶蒿是TΛ7的ANPP增加的主要贡献者。这些结果表明，当7月降水量达到年平均降水量的41.6%，且其他月份满足植物基本生长需求时，短花针茅荒漠草原实现了最大生产力。本研究强调实施管理措施（灌溉或人工降水）以实现牧草产量最大化，并预测荒漠草原的植物组成。
