Landscape Heterogeneity and Net Primary Productivity (NPP) of Mountain-Oasis-Desert Ecosystems in Western China

摘要

This study was conducted to develop an appropriate assessment technique to define impact of mountain-desert-oasis ecosystem on net primary productivity (NPP) in northern foothills of Tianshan Mountains. Geographic Information System (GIS) was used to estimate land use/land cover of the mountain, desert and oasis zones. An ecological process model was used to estimate NPP by using data entirely derived from satellite. The results show that landscape heterogeneity was important factor to affect NPP values in mountain-desert-oasis ecosystem. Simulated results indicated a total annual NPP of 1.5081 x 10~(14) g C for selected transect in 2002. There was 32.67% of total NPP which came from oasis areas, 28.16 % from alpine meadows areas. 9.15% from forests area. Mean NPP values over the selected transect was 150.29 g Cm~(-2) year~(-1) in 2002. However, NPP values varied greatly with different geography and season.