Analysis of Temporal-Spatial Characteristics and Factors Influencing Vegetation NPP in Northeast China from 2000 to 2006
Vegetation is an important component of terrestrial ecosystems and plays an important role in global matter and energy cycles, as well as carbon balance and climate change. Net Primary Productivity ( NPP) is the accumulation of organic matter by green plants per unit of space and time. NPP indicates the growth status of vegetation, and provides information for the management of renewable biological resources. Study of changes in vegetation NPP and the relationship with climatic change is significant in Northeast China, a region which is sensitive to global change. We analyzed spatio-temporal characteristics of vegetation NPP and influencing factors in Northeast China from 2000 to 2006 based on MOD 17A3 data from EOS/MODIS (TERRA) . Results showed that the range of NPP in the northeast was mainly between 200 and 400gC/(m2 ·a) , and average annual NPP in the northeast (400.85gC/(m2·a) ) was higher than the national average during the same period (360.97gC./(m2 · a)). The average annual NPP in the forested areas of the Changbai Mountains, Greater Hinggan Mountains and Xiaoxing' anling Mountains, with values from 400 to 600gC7(m2 ·a) , was higher than NPP values for the agricultural areas of the Liao River Plain, Songnen Plain and Sanjiang Plain and the eastern Hulunbuir Grasslands((200 ~ 400)gC/(m2 · a) ) . The lowest NPP Yalues were in the western part of the temperate tufted grass steppes of Hulunbuir and the mixed farm-pasture area of the western Songnen Plain and Chifeng in the Inner Mongolia Autonomous Region, which ranged from 0 to 200gC/(m2 ·a). In terms of the average annual NPP of the main vegetation types in the Northeast, mixed needleleaf-broadleaf forest had the highest value, of 572.56gC/(m2·a) . Other vegetation types (broadleaf forests, needleleaf forests, marsh, cropland and scrub) had decreasing NPP values in that order, of 473.93gC, 454.42gC, 432.90gC, 378.21g€ and 377.33gC/(m·a) respectively. The lowest value was found in grassland (312.45g€/( m2·a)). Univariate linear regression was used to simulate the trends of change in average annual NPP in Northeast China from 2000 to 2006. The overall trend for the entire area showed very little change, but area with increased NPP accounted for 30.51% of total area in Northeast China, and area with decreased NPP accounted for 27.43% . Land cover change was an influential factor affecting changes in vegetation NPP in Northeast China during the study period. Regression analysis of vegetation NPP and climate factors showed that precipitation was the key factor controlling terrestrial NPP in the region.
NETL
NSTL
万方数据
维普
