Spatial-temporal variability of land use with terrain gradient in Taihang Mountain, Hebei Province

Terrain significantly influences land use change and spatial pattern. Compared with the single terrain factor (elevation, slope) method, terrain niche index, combination of elevation and slope, can reflect detailed spatial variability of terrains. Distribution index can describe the differences between actual and standard distribution of different land use types, excluding the disturbances of the area. The comprehensive index of land use degree can reflect regional land use intensity and is suitable for comprehensive evaluation of land use degree. Taking advantage of GIS spatial capabilities along with terrain niche index, distribution index and comprehensive index of land use degree, this study analyzed land use patterns and changes in Taihang Mountain in Hebei Province from 1990 to 2008. Also the land use degree on terrain gradient was quantitatively analyzed and terrain influence on land use selection pattern was explored. The results showed that the spatial distributions and changes in various land use types were considerably influenced by terrain factors. Arable land, construction land, water and unused land were mainly in areas with 0° 15° slope and <500 m altitude. Also the changing areas of land use on these terrains were highest. Arable land, construction land, water and unused land were mainly in areas with low terrain niche index. Then grassland was mainly in areas with medium terrain niche index and woodland in areas with medium-to-high terrain niche index. With increasing terrain niche index, the distribution index of arable land decreased, that of grassland, construction land, water and unused land decreased followed by an increase, while that of woodland increased. From 1990 to 2008, predominant distribution terrain niche index scale of woodland increased by two units. That of grassland expanded by three units in the middle terrain niche section but reduced the sections with high terrain niche. That of water expanded in low terrain niche section, and that of unused lands reduced significantly. Then those of arable land and construction land generally remained stable during the study period. Additionally, the comprehensive index of land use degree reduced with increasing terrain niche index. Based on quantitative analysis of the land use degree on terrain gradients, terrain niche was divided into three sections. They were dominant terrain niche section of arable land, water, construction land and unused land; dominant terrain niche sections of grassland and woodland; and dominant terrain niche section of woodland. The areas of the three sections were 45.79%, 41.30% and 12.91% of the study area. Finally, suggestions were put forward for rational use of land resources and ecological environment restoration in Taihang Mountain in Hebei Province.