JOURNAL OF NATURAL RESOURCES ›› 2017, Vol. 32 ›› Issue (11): 1844-1856.doi: 10.11849/zrzyxb.20160983

• Resource Ecology • Previous Articles     Next Articles

The Responses of the Net Primary Productivity of the Dryland Ecosystems in Central Asia to the CO2 and Climate Changes during the Past 35 Years

ZHU Shi-hua1, 2, 3, YAN Yan2, 3, SHAO Hua2, LI Chao-fan2, 4   

  1. 1. International Institute for Earth System Science, Nanjing University, Nanjing 210093, China;
    2. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, CAS, Urumqi 830011, China;
    3. University of Chinese Academy of Sciences, Beijing 100049, China;
    4. School of Geography and Remote Sensing, Nanjing University of Information Science and Technology, Nanjing 210008, China
  • Received:2016-09-14 Revised:2016-11-19 Online:2017-11-20 Published:2017-11-20
  • Supported by:
    National Natural Science Foundation of China, No.U1503301 and 41401118; National Basic Research Programs of China, No.2014CB954204

Abstract: More than 80% of world's temperate desert locates in Central Asia, dryland that experienced strong warming and significant changes in precipitation pattern in recent decades. The objectives of this study was to quantify spatio-temporal patterns of net primary productivity in Central Asia over the past 35 years, and investigate the relative contribution and interactive effect of climate controls including temperature, precipitation and CO2, using the Arid Ecosystem Model (AEM), which performed well in predicting the dryland ecosystems' responses to climate changes according to our evaluation. The results show the 35-year averaged annual NPP of Central Asia amounted to 1 125±129 Tg C/a (1 T=1012), or 218±24 g C /(m2·a), with an overall declining trend of 0.71 g C/(m2·a). The northern Kazakhstan had relatively high NPP of 349±39 g C/(m2·a), while the southern Xinjiang of China had relatively low NPP of 123±45 g C/(m2·a). During the last 35 years, the NPP of the southern Xinjiang subregion declined significantly with a trend of -2.05 g C/(m2·a). Comparing the NPP during 1985-2014 to the NPP during 1980-1984, we found the regional NPP decreased 118 Tg or 10%, with positive contribution of 35.4 Tg or +2% from temperature change, positive contribution of 99.7 Tg or +8% from CO2 change, negative contribution of 221 Tg or -18% from precipitation change. The temperature was the dominant factor on NPP in 9% of the study area, mainly in the Tianshan Mountains and northern Kazakhstan, where the temperature increased by 0.03 ℃/a during 1980-2014. Precipitation was the dominant factor on NPP in 69% of the study area, mainly in the desert subregion and the dryland of southern Xinjiang of China, where the vegetation was limited by water. CO2 was the dominant factor on NPP in 20% of the study area, mainly in the lower altitude regions of Tianshan Mountains, where the hydrothermal condition was suitable for vegetation growth. This study shows that the southern Xinjiang of China is the fragile eco-environmental subregion in Central Asia, whose ecosystem security is facing the challenges of climate change. However, increasing temperature is unlikely to stimulate autotrophic respiration and cause a significant impact on regional NPP in Central Asia.

Key words: arid ecosystem model, Central Asia, climate change, dryland, NPP

CLC Number: 

  • Q948.1