Landscape pattern changes at a catchment scale: a case study in the upper Jinjing river catchment in subtropical central China from 1933 to 2005

Land use and cover changes have been reported to have a great association with the alteration of regional ecological functions, and, thus, pose significant changes to the environmental quality. The analysis of landscape pattern changes is regarded as one of the most important prerequisites to quantify such land use and cover changes. Four-year land use maps (1933, 1955, 1990, and 2005) of the upper Jinjing river catchment in Hunan Province in subtropical central China, consisting of an area of 13,500 ha and containing three administrative districts (ADs) (Jinjing, Guanjia, and Tuojia), were used for analyzing the landscape pattern changes. Our results showed that a major landscape pattern has been established since 1933. A moderate changing trend, the decrease of woodland resulting from the increase of paddy field, was also observed. From 1933 to 2005, 1,270 ha of woodland were converted to paddy field, accounting for 13 % of the woodland present in 1933. An analysis of landscape indices demonstrated that the catchment landscape became more heterogeneous from 1933 to 1990, and that the patch fragmenting trend has remained fairly stable since 1990. Compared to the other two ADs, Jinjing showed a contrasting trajectory in the temporal trend of the largest patch index, indicating a distinct urbanization in that AD since 1990. Guanjia showed a different temporal trend in the perimeter-area fractal dimension, suggesting that this district was experiencing disordered development, and, thus, a comprehensive planning should be a concern. The predominant driving forces for the land use changes were found to be the terrain and the governmental policies. Climate change and anthropogenic activities (e.g., rapid population growth and migration) may also be important factors that have impacted the landscape changes of the studied catchment.