State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
Sci Total Environ. 2019 Feb 25;653:1311-1325. doi: 10.1016/j.scitotenv.2018.11.058. Epub 2018 Nov 6.
In recent decades, climate change and human activities have severely affected grasslands in Central Asia. Grassland regulation and sustainability in this region require an accurate assessment of the effects of these two factors on grasslands. Based on the abrupt change analysis, linear regression analysis and net primary productivity (NPP), the spatiotemporal patterns of grassland ecosystems in Central Asia during 1982-2015 were studied. Further, the potential NPP (NPP) was estimated using the Thornthwaite Memorial model and the human-induced NPP (NPP), which was the difference between NPP and actual NPP, were used to differentiate the effects of climate change and human activities on the grassland ecosystems, respectively. The grassland NPP showed a slight upward trend during 1982-2015, while two obvious decreasing periods were found before and after the mutation year 1999. Additionally, the main driving forces of the grassland NPP variation for the two periods were different. During 1982-1999, climate change was the main factor controlling grassland NPP increase or decrease, and 84.7% of grasslands experienced NPP reduction, while the regions experiencing an increase represented only 15.3% of the total area. During 1999-2015, the areas of increasing and decreasing grassland NPP represented 41.6% and 58.4% of the total area, respectively. After 1999, human activities became the main driving force of the NPP reduction, whereas climate change facilitated grassland restoration. The five Central Asian countries showed widely divergent relative impacts of climate change and human activities on NPP changes. In Uzbekistan and Turkmenistan, anthropogenic decreases in grassland NPP intensified during 1982-2015, while the negative anthropogenic effects on grassland NPP in Kyrgyzstan and Tajikistan moderated. Further analysis identified precipitation as the major climatic factor affecting grassland variation in most areas of Central Asia and overgrazing as the main form of human activity accelerating grassland degradation. This study improves the understanding of the relative impacts of climate change and human activities on grasslands in Central Asia.
近几十年来，气候变化和人类活动严重影响了中亚的草原。该地区的草原管理和可持续性需要准确评估这两个因素对草原的影响。本研究基于突变分析、线性回归分析和净初级生产力（NPP），研究了 1982-2015 年中亚草原生态系统的时空格局。进一步，利用 Thornthwaite Memorial 模型估算潜在 NPP（NPP），用 NPP 与实际 NPP 的差值来区分气候变化和人类活动对草原生态系统的影响。结果表明，1982-2015 年，草原 NPP 呈微弱上升趋势，突变年份 1999 前后存在明显的两个下降期。此外，两个时期草原 NPP 变化的主要驱动力不同。1982-1999 年，气候变化是控制草原 NPP 增减的主要因素，84.7%的草原 NPP 呈下降趋势，而增加的区域仅占总面积的 15.3%。1999-2015 年，草原 NPP 增加和减少的面积分别占总面积的 41.6%和 58.4%。1999 年后，人类活动成为 NPP 减少的主要驱动力，而气候变化有利于草原恢复。中亚五国在气候变化和人类活动对 NPP 变化的相对影响方面表现出明显的差异。在乌兹别克斯坦和土库曼斯坦，1982-2015 年人为减少草原 NPP 的趋势加剧，而吉尔吉斯斯坦和塔吉克斯坦的人为对草原 NPP 的负面影响减弱。进一步分析表明，降水是影响中亚大部分地区草原变化的主要气候因素，过度放牧是加速草原退化的主要人类活动形式。本研究提高了对气候变化和人类活动对中亚草原相对影响的认识。
