Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (4): 798-809.DOI: 10.3773/j.issn.1005-264x.2008.04.008

• Original article • Previous Articles     Next Articles


ZHANG Feng, ZHOU Guang-Sheng()   

  1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • Received:2007-09-13 Accepted:2008-01-23 Online:2008-09-13 Published:2008-07-30
  • Contact: ZHOU Guang-Sheng


Aims Net primary productivity (NPP) and its responses to global climate change have been important issues of global change research. Accurately estimating spatial patterns and temporal dynamics of NPP of terrestrial ecosystems is important to human society and is necessary for understanding the carbon cycle of the terrestrial biosphere. The Northeast China Transect (NECT), one of the International Geosphere-Biosphere Programme terrestrial transects, is an ideal region for identifying effects of climate change on spatial-temporal variations in NPP.

Methods We investigated NPP derived from a carbon model (Carnegie-Ames-Stanford Approach, CASA) and its spatial-temporal variations along NECT 1982-1999 time series data sets of normalized difference vegetation index (NDVI) at 8 km spatial resolution and paired ground-based information on vegetation, climate, soil and solar radiation, after validating the CASA model using NPP data from 33 stations along NECT.

Important findings The 18-year averaged annual NPPalong NECT was 426 g C·m-2·a-1, ranging from 58 to 811 g C·m-2·a-1 and decreased from east to west, which is consistent with the distribution of precipitation. Total annual NPP changed from 0.218 to 0.325 Pg C over the 18 years, with an average of 0.270 Pg C. Two distinct periods (1982-1990 and 1991-1999) of NPP variations were observed, separated by a sharp reduction during 1990-1991. From 1982 to 1990, a significant increase of 0.007 5 Pg C·a-1 was observed; from 1991 to 1999, annual NPP showed no marked trend. From 1982 to 1999, annual NPP showed a significant increase, accounting for 56.65% of the whole transect, and the largest annual NPP increase during 1982-1999 appeared in cultivated land, typical steppe and meadow steppe, accounting for 62.6% of the increment of the whole region, while desert steppe and typical steppe showed higher sensitivity to climate change. Spatial distribution of NPP along NECT is determined by the pattern annual precipitation, and temporal variation of NPP is influenced by changes in annual precipitation and annual total solar radiation.

Key words: CASA model, net primary productivity, Northeast China Transect (NECT)