Abstract: Net Primary Productivity (NPP) is an important indicator to characterize the production capacity and quality of terrestrial ecosystems. Previous studies are mainly based on large and middle scale units and pay more attention to semi-humid and humid areas, therefore we select National Nature Reserve of Populus euphratica in Tarim Basin, Xinjiang, China as the study area. Based on the NPP, climate, land use/land cover, river data and using trend analysis, Mann-Kendall test, correlation analysis and geographical detector methods, this paper analyzed the temporal-spatial characteristics and influencing factors of the vegetation net primary productiuity; temporal-spatial distribution; geodetector; National Nature Reserve of Populus euphratica in Tarim in the National Nature Reserve of Populus euphratica in Tarim from 2000 to 2015.The results are as follows: First,the average vegetation NPP from 2000 to 2015 was 32.25 gC·m^-2·a^-1 and ranged from 5.16-303.87 gC·m^-2·a^-1.The average NPP was declined as the belt form from the two wings of Tarim River to the place far away from the river. Different vegetation types contribute differently to annual vegetation NPP growth, and NPP tended to increase the most for broadleaf forest, but least for shrublands. Second, the NPP followed an overall trend of fluctuating growth with 0.523 8 gC·m^-2·a^-1 every year. The NPP had a sharp growth trend during the period from 2001 to 2002 and the period from 2011 to 2012 and drastically reduced during the period from 2007 to 2008.Last,there are many factors affecting NPP, mainly including land use/land cover, evapotranspiration, precipitation and river buffer zone, and the NPP changes were mainly caused by the synergistic effect of multiple factors. The groundwater depth had a significant influence on vegetation NPP. This study provides decision support for the ecological environment protection and governance of National Nature Reserve of Populus euphratica in Tarim Basin, and provides a reference frame for maintaining the ecosystem sustainability of the green ecological corridor in Tarim River.

Key words: net primary productiuity, temporal-spatial distribution, geodetector, National Nature Reserve of Populus euphratica in Tarim