Fan Lian-Lian, Mekrovar Okhonniyozov, Li Yao-Ming, Li Kai-Hui, Ma Xue-Xi, Mao Jie-Fei
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.
Research Center for Ecology and Environment of Central Asia, Chinese Academy of Sciences, Urumqi, China.
Front Plant Sci. 2021 Dec 10;12:765077. doi: 10.3389/fpls.2021.765077. eCollection 2021.
Grasslands provide key resource for the millions of people who are dependent on livestock in Tajikistan. Productivity and species richness (SR) are important characteristics of grassland ecosystems and are greatly affected by nutrient inputs. The effect that climate change might have on these characteristics remains unclear. Here, an nitrogen (N) and phosphorus (P) fertilization experiment was conducted at four sites along with an elevational gradient (650, 1,100, 1,250, and 2,000 m) in western Tajikistan over 2 years (2018 and 2019) to examine the influences of nutrient availability and climate change on aboveground biomass (AGB) and SR; precipitation and temperature were also considered to analyze the responses. It demonstrated that enrichment with N, P, and their combinations significantly increased AGB along with an elevational gradient ( < 0.05). AGB increased as the concentrations of nutrients added increased. The maximum AGB, which was 2-fold higher compared with control, was observed when 90 kg N hayear and 30 kg P hayear were added. In addition, nitrogen addition alone stimulated greater AGB than P addition, although no significant difference was observed between these two treatments. Enrichment with N, P, and their combination had no significant effect on SR; however, SR significantly changed at different elevation. Elevation had direct effect on precipitation and temperature, which, in turn, resulted in variation in AGB and SR. Moreover, both nutrient and elevation had significant effect on AGB and SR, but there was no interaction effect of them. AGB and SR interacted with significant negative correlation. In the high-elevation area, plants grew better in the warmer year (2018); this indicates that grasslands in high mountain areas in Tajikistan might have higher productivity as the climate warms, which will positively affect the economic development of the country.
草原为塔吉克斯坦数百万依赖牲畜为生的人提供了关键资源。生产力和物种丰富度（SR）是草原生态系统的重要特征，并且受到养分输入的极大影响。气候变化可能对这些特征产生的影响仍不清楚。在此，在塔吉克斯坦西部沿海拔梯度（650、1100、1250和2000米）的四个地点进行了为期两年（2018年和2019年）的氮（N）和磷（P）施肥实验，以研究养分有效性和气候变化对地上生物量（AGB）和SR的影响；还考虑了降水和温度以分析其响应。结果表明，添加N、P及其组合进行富集沿着海拔梯度显著增加了AGB（P<0.05）。AGB随着添加养分浓度的增加而增加。当每年添加90千克N和30千克P时，观察到最大AGB，与对照相比高出2倍。此外，单独添加氮比添加磷刺激产生更大的AGB，尽管这两种处理之间未观察到显著差异。添加N、P及其组合进行富集对SR没有显著影响；然而，SR在不同海拔处显著变化。海拔对降水和温度有直接影响，进而导致AGB和SR的变化。此外，养分和海拔对AGB和SR均有显著影响，但它们之间没有交互作用。AGB和SR之间存在显著的负相关。在高海拔地区，植物在较温暖的年份（2018年）生长得更好；这表明随着气候变暖，塔吉克斯坦高山地区的草原可能具有更高的生产力，这将对该国的经济发展产生积极影响。
