Abstract: Based on the VPM model,we obtained the NPP data(NPP_u&i)through using the improved neighborhood substitution method(i.e.,the NPP(NPP_pot)of crop land or vegetable land occupied by urban and industrial land which is newly expanded between year t and year t+5(data interval of 5 years)were taken place by the vegetation types in year t within 10 km of the same area)to retrieve NPP_pot during 2000-2015 and further analyzed its spatio-temporal pattern characteristics,and explained the causes of NPP loss caused by urban and industrial land transformation. The results show that urban and industrial land in 2015 accounted for about 1.21% of total land area and the expansion area of urban and industrial land in China during 2000-2015 was 72×10³ km². The loss of net primary productivity due to urban and industrial land expansion was about 1.24×10⁴ tC·a^-1 to 3.14×10⁴ tC·a^-1,the highest loss was in 2005-2010. The major cause of NPP loss was cropland converted into urban and industrial land. During 2010-2015,13.28×10³ km² of cropland had been converted into urban and industrial land,resulting in a NPP loss of 151.09×10⁴ tC·a^-1,accounting for 82% of the total loss of the total ecosystem productivity. From the spatial perspective,severe urban expansion in the early 21^st century resulted in severe NPP losses in the coastal and central regions(up to 81.75×10⁴ tC·a^-1 in coastal areas in 2005)and the NPP losses (45.50×10⁴ tC·a^-1 in 2015,accounting for 30.81% of the total loss)in the western region were mainly due to the expansion of industrial land expansion in the late 21^st century. The loss of ecosystem productivity gradually changed from the pattern of eastern higher than western to the east-west balance. For the mechanism analysis,the percentage of ISA(0.59 ±0.19)was higher than that of natural vegetation(0.29 ±0.14),and the mean normalized NPP(0.9)of permeable surface in the urban interior was lower than that of the natural vegetation(1.1), which was the main reason for the loss of NPP in urban and industrial land. By assessing the ecological and environmental consequences brought by urbanization and industrialization,it is very helpful to optimize the pattern of urban land use rationally and prevent urban ecological environmental risks.

Key words: expansion of urban and industrial land, NPP, remote sense, China