Decadal loss of paddy fields driven by cumulative human activities in the Three Gorges Reservoir area, China

Paddy fields are valuable agricultural land resources in the Three Gorges Reservoir area of China but have been threatened by the expansion and intensification of human activities over recent decades. How paddy fields evolve under human disturbances remains poorly understood, which is critical for land use planning to compromise agricultural production and ecosystem conservation as limited land resource is available. In this study, the spatial and temporal patterns of change in paddy fields were depicted and principal driving forces were explained. Mapping of paddy fields with LANDSAT satellite images reveals a constant declining trend by 14.3% in the period 1990–2015. The gross loss area is 903.3 km2, with an annual average decreasing rate being 36.1 km2·yr−1. The transformation matrix between paddy fields and other land uses explicitly explains the impact trajectories of multiple human activities. Specifically, 39.6% (408.1 km2) of the gross loss was converted to built‐up lands, reflecting town translocation and human resettlement (involuntary population migration) proposed by construction of the Three Gorges Dam, as well as urbanization, industrial development and infrastructure expansion along with economic development. The area converted to forests accounts for 26.4% (238.2 km2), which could be ascribed to land abandonment and the reforestation campaign. 23.1% (208.7 km2) was converted to dry croplands by shifts in farmers' preference on crop selection following socioeconomic changes (e.g., voluntary rural population migration, land use policy adjustment, commercial farming enterprises expansion). 46.5 km2 was converted to water bodies, indicating the effect of impoundment of the Three Gorges Reservoir.