Abstract:

Land-use change is closely related to the human disturbance. Dam construction alters the land-use of a reservoir's surroundings, ultimately affecting the transport of matters from terrestrial ecosystem to the ocean through inland waters. Taking the Hongjiadu Reservoir in Wujiang River as an example, a land-use transfer matrix was applied to discuss the dam-induced change in land-use in the Hongjiadu Reservoir catchment at both the catchment scale and landscape scale. Results showed as follows. From a time scale perspective, land-use change mainly occurred in the second stage after reservoir impoundment. In the first stage, the overall change of Hongjiadu Reservoir catchment was that the cropland area decreased by 91.33 km$^{2}$, while the forest, grassland, water and urban areas increased by 26.54, 8.84, 55.51 and 0.45 km$^{2}$, respectively. In the second stage, the cropland, forest and grassland areas decreased by 230.98, 30.17 and 42.88 km$^{2}$, respectively, while water and urban areas increased by 9.07 and 295.46 km$^{2}$, respectively. At the spatial scale, the land-use change was mainly concentrated in the vicinity of Hongjiadu Reservoir, in the decrease of cropland areas and the increase of grassland areas. The land-use type changed the most within the 0-1 km buffer zone at the reservoir's landscape scale, mainly manifested as water becoming grassland and urban becoming cropland. Different land-use types were inundated to form the reservoir area after the construction of Hongjiadu dam, which with the greatest impact on the land-use change within the 0-1 km buffer zone of the reservoir.

Key words: land-use conversion matrix, dynamic change, reservoir, buffer zone, catchment