Chin J Plant Ecol ›› 2009, Vol. 33 ›› Issue (2): 254-269.DOI: 10.3773/j.issn.1005-264x.2009.02.003

Special Issue: 青藏高原植物生态学:遥感生态学

• Research Articles • Previous Articles     Next Articles

SPATIAL-TEMPORAL PATTERNS OF NET PRIMARY PRODUCTIVITY FOR 1988-2004 BASED ON GLOPEM-CEVSA MODEL IN THE “THREE-RIVER HEADWATERS” REGION OF QINGHAI PROVINCE, CHINA

WANG Jun-Bang(), LIU Ji-Yuan, SHAO Quan-Qin, LIU Rong-Gao, FAN Jiang-Wen, CHEN Zhuo-Qi   

  1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101
  • Received:2008-01-08 Accepted:2008-07-10 Online:2009-03-31 Published:2009-03-31

Abstract:

Aims The “Three-River Headwaters” Region, as the headwaters of important rivers and an area sensitive to global climate change, has become a recent research focus. Our objective is to model and assess the spatial-temporal pattern of net primary production ( NPP) and its control mechanisms.

Methods We applied the GLOPEM-CEVSA model, which has been validated with carbon flux observation in forest, grassland and cropland. The main inputs are spatially interpolated meteorological data and fraction of photosynthetically active radiation absorbed by vegetation canopy, using 1 km resolution of the Advanced Very High Resolution Radiometer of the National Oceanic and Atmospheric Administration in 1988-2004.

Important findings Modeled NPP ranged from 36.13 gC·m-2·a-1 for desert to 267.90 gC·m-2·a-1 for forest, and the mean was 143.17 gC·m-2·a-1. Spatially, NPP decreased from southeast to northwest, as influenced by geography and climate. Variability of NPP was the largest in desert (41.75%), was similar for cropland (25.93%), grassland (22.31%) and wetland (24.72%) and was the smallest in forest (20.79%). During 1988-2004, NPP increased at the rate of 7.8-28.8 gC·m-2 per 10 years in the western area, but decreased 13.1-42.8 gC·m-2 per 10 years in the central and eastern areas. At 99 and 95% significance levels, the area with NPP increasing (regression slope b > 0) was 13.43% and 20.34%, respectively, of the whole area, and mainly distributed in the western region, while the area with NPP decreasing (b < 0) was 0.75% and 3.77%, respectively, of the whole area and distributed in the central and western areas and was more concentrated near the main rivers at higher significance levels. Increases of NPP in the western area may have been affected by increasing temperature and precipitation, while central and eastern areas may have been impacted by human activities, especially along the Yangtze, Yellow and other rivers with intensive human habitation and where the warmer and drier climate has led to more serious grassland degradation. The effects of human activities on NPP were not analyzed because data on human activity were unavailable and spatial interpolation of the impact is difficult.

Key words: “Three-River Headwaters” Region, Qinghai, net primary productivity, GLOPEM-CEVSA