Impacts of land use and climate change on the net primary productivity in XinJiang based on remote sensing

Arid and semi-arid ecosystems exhibit a spatially complex biogeophysical structure. According to arid western special climate-vegetation characters, using the remote sensing spectral mixture analysis. The study developed a modified production efficiency model Net Primary Productivity-Geography Processing Ecology Model (NPP-GPEM) appropriate for the arid area at regional scale based on the concept of radiation use efficiency. Combined with recent historical period climate data and two periods of land use data sets from remote sensing data, we test the net primary productivity (NPP) data sets over last 20 years in XinJiang of the North China modelled by the NPP-GPEM with the satellite data-driven for detecting the wide spread spatial temporal characteristics of the impacts of climate and land use change impact with the regional NPP. Our results shows that over past 20 years, the average annual temperature in the research region has remarkably increased by more than 0.056°C, but over the same period, there has been a 0.635mm increase in annual precipitation and increase in NPP by an annual rate of 0.142TgC. Taking use of 16 land covers of Xinjiang which was carried on the calculation of the matrix transfer, the study got the matrix of the NPP changes over past 20 years. The result found that the quicker trend increasing is the others woodlands (the 5.51gC/m2/yr) and the oasis farmland (4.32 gC/m2/yr). The pasture area is the biggest to about 29.3% of total area, the pasture growth is smaller than others, but its increase to the contribution rate of the annual NPP in the whole land ecosystem system biggest is pasture and agricultures to land use covers, that had the total annual NPP increase with 52.2% and 19.9% of the quantity respectively, the plant cover is only the shrub pant which has a absolute decrease ecosystem system in the type (- 14.39gC/m2); In fine, the paper mainly reveals the dissimilarities and conversion among the pasture, farmland, woodland and different covered pasture and other types. The correlation analysis between annual NPP and annual precipitation was highly consistent with plant cover spatially (R2=0.64, P<0.01) in the overall XinJiang, and the northern of XingJiang is better than the southern of it, and the correlation coefficient changes with the changes of vegetation types and different regions. The analysis revealed that the climate changes dominate the impacts on the NPP in the whole study region. However, land use plays a dominative role in the areas with land cover changes. Over past 20 years, the NPP in the whole study region remarkably increased due to obvious precipitation decrease and temperature rise. Between two periods of land use (about 10 years), the changes in climate are predicted to cause increases in NPP, and combined impacts of climate changes and land use to cause to increase in NPP.

[1]  F. Woodward,et al.  Dynamic responses of terrestrial ecosystem carbon cycling to global climate change , 1998, Nature.

[2]  Li Hui-guo.  Estimating Net Primary Productivity of TerrestrialVegetation in China Using Remote Sensing , 2002 .

[3]  Scott J. Goetz,et al.  Remotely Sensed Interannual Variations and Trends in Terrestrial Net Primary Productivity 1981–2000 , 2004, Ecosystems.

[4]  D. Roberts,et al.  Endmember selection for multiple endmember spectral mixture analysis using endmember average RMSE , 2003 .

[5]  Mingkui Cao,et al.  Increasing terrestrial carbon uptake from the 1980s to the 1990s with changes in climate and atmospheric CO2 , 2002 .

[6]  S. Goward,et al.  Global Primary Production: A Remote Sensing Approach , 1995 .

[7]  Laia Andreu Hayles,et al.  Climate and Atmospheric CO2 Effects on Iberian Pine Forests assessed by Tree-Ring Chronologies and their potential for Climatic Reconstructions , 2007 .

[8]  C. Tucker,et al.  Satellite remote sensing of total dry matter production in the Senegalese Sahel , 1983 .

[9]  Taobo,et al.  The temporal and spatial patterns of terrestrial net primary productivity in China , 2003 .

[10]  J. Monteith.  SOLAR RADIATION AND PRODUCTIVITY IN TROPICAL ECOSYSTEMS , 1972 .

[11]  J F Reynolds,et al.  Biological Feedbacks in Global Desertification , 1990, Science.

[12]  W. Cramer,et al.  The IIASA database for mean monthly values of temperature , 1991 .

[13]  Shao Xuemei,et al.  The temporal and spatial patterns of terrestrial net primary productivity in China , 2003 .

[14]  Liu Jiyuan,et al.  Impacts of land use and climate change on regional net primary productivity , 2004 .

[15]  Pan Xiaoling,et al.  The effects of climate on development of ecosystem in oasis , 2001 .

[16]  Gregory P. Asner,et al.  Desertification alters regional ecosystem–climate interactions , 2005 .

[17]  J. Monteith.  Climate and the efficiency of crop production in Britain , 1977 .

[18]  S. Goetz,et al.  Modelling Terrestrial Carbon Exchange and Storage: Evidence and Implications of Functional Convergence in Light-use Efficiency , 1999 .

[19]  S. Goetz,et al.  Variability in carbon exchange and light utilization among boreal forest stands: implications for remote sensing of net primary production , 1998, Canadian Journal of Forest Research.

[20]  Makiko Sato,et al.  Satellite and surface temperature data at odds? , 1995 .

[21]  S. Goetz,et al.  Remote sensing of net primary production in boreal forest stands , 1996 .

[22]  C. Tucker,et al.  Satellite remote sensing of rangelands in Botswana II. NOAA AVHRR and herbaceous vegetation , 1986 .

[23]  C. Tucker,et al.  Satellite remote sensing of primary production , 1986 .

[24]  William H. Schlesinger,et al.  Desertification alters patterns of aboveground net primary production in Chihuahuan ecosystems , 2002 .

[25]  G. Collatz,et al.  Physiological and environmental regulation of stomatal conductance, photosynthesis and transpiration: a model that includes a laminar boundary layer , 1991 .

[26]  J. Randerson,et al.  Terrestrial ecosystem production: A process model based on global satellite and surface data , 1993 .

[27]  M. Steven,et al.  Estimation of sugar beet productivity from reflection in the red and infrared spectral bands , 1983 .

[28]  S. Prince.  Satellite remote sensing of primary production: comparison of results for Sahelian grasslands 1981-1988 , 1991 .

[29]  J. Randerson,et al.  Global net primary production: Combining ecology and remote sensing , 1995 .