Spatiotemporal variation of vegetation net primary productivity and its driving factors from 2000 to 2015 in Qinling-Daba Mountains, China.

Abstract

We analyzed spatiotemporal changes in vegetation net primary productivity (NPP) in the Qinling-Daba Mountains based on MOD17A3 data and driving factor data from 2000 to 2015. We used trend analysis, Hurst index, and correlation analysis to examine the effects of climate change, soil type, topographic factors, vegetation type, and human activities on NPP. With respect to spatial variation, NPP was the highest in southwestern area and lowest in the northeast. The temporal trend over the 16-year period showed that NPP was increased in the northwest and decreased in the northeast. The projected trend of NPP was of continuity in northern area and anti-continuity in southern area of the Qinling-Daba Mountains. NPP was positively correlated with precipitation and temperature. NPP in areas with dark-brown earths, yellow earths, purplish soils and paddy soils were significantly higher than those with other soil types. The spatial distribution and trends of NPP differed among vegetation types. High NPP mainly occurred on slopes of 25° to 50° and altitudes of 500 to 1000 m or above 2500 m. Human activities had both positive and suppressive effects on NPP.