Journal of Resources and Ecology ›› 2016, Vol. 7 ›› Issue (6): 418-429.DOI: 10.5814/j.issn.1674-764x.2016.06.002

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Climatic and Topographical Factors Affecting the Vegetative Carbon Stock of Rangelands in Arid and Semiarid Regions of China

REN Zhengchao1, 2, *, ZHU Huazhong3, SHI Hua4, LIU Xiaoni1   

  1. 1. College of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, China;
    2. Key Laboratory of Grassland Ecology System (Gansu Agricultural University), Ministry of Education, Lanzhou 730070, China;
    3. Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China;
    4. ASRC Federal InuTeq, Earth Resources Observation and Science (EROS) Center, Sioux Falls SD57198, USA
  • Received:2016-03-24 Revised:2016-09-05 Online:2016-11-15 Published:2016-11-15
  • Contact: REN Zhengchao. Email: renzhengchao2008@163.com
  • Supported by:
    National Natural Science Foundation of China (30960264 and 31160475), Science and technology program of Gansu province (1107RJYA058), open project of Key Laboratory of Grassland Ecosystem (Gansu Agricultural University), Ministry of Education (CYZS-2011014) and Fund of technology innovation commemorated Sheng Tongsheng in Gansu Agricultural University (GSAU-STS-1304 and GSAU-STS-1505).

Abstract: Rangeland systems play an important role in ecological stabilization and the terrestrial carbon cycle in arid and semiarid regions. However, little is known about the vegetative carbon dynamics and climatic and topographical factors that affect vegetative carbon stock in these rangelands. Our goal was to assess vegetative carbon stock by examining meteorological data in conjunction with NDVI (normalized difference vegetation index) time series datasets from 2001-2012. An improved CASA (Carnegie Ames Stanford Approach) model was then applied to simulate the spatiotemporal dynamic variation of vegetative carbon stock, and analyze its response to climatic and topographical factors. We estimated the vegetative carbon stock of rangeland in Gansu province, China to be 4.4× 1014 gC, increasing linearly at an annual rate of 9.8×1011 gC. The mean vegetative carbon density of the whole rangeland was 136.5 gC m-2. Vegetative carbon density and total carbon varied temporally and spatially and were highly associated with temperature, precipitation and solar radiation. Vegetative carbon density reached the maximal value on elevation at 2500-3500 m, a slope of >30°and easterly aspect. The effect of precipitation, temperature and solar radiation on the vegetative carbon density of five rangeland types (desert and salinized meadow, steppe, alpine meadow, shrub and tussock, and marginal grassland in the forest) depends on the acquired quantity of water and heat for rangeland plants at all spatial scales. The results of this study provide new evidence for explaining spatiotemporal heterogeneity in vegetative carbon dynamics and responses to global change for rangeland vegetative carbon stock, and offer a theoretical and practical basis for grassland agriculture management in arid and semiarid regions.

Key words: climatic environment, rangeland system, spatiotemporal change, topographical condition, vegetative carbon stock