Relationship between the vegetation types and topographical factors from Wula mountain, Inner Mongolia: Based on ALOS data

The vegetation map, with a complex landform of DAHUABEI region in Wula mountain was produced based on the field vegetation investigation, and image interpretation, using the ALOS data and a Digital Elevation Model (DEM). The spatial distribution of the main vegetation types and their relations with topographical factors were statistically analyzed under the support of GIS, combining the vegetation map and topographical factors in the study area. The results showed that, (1) vegetation types showed a distinct vertical spectrum, from low to high elevations as follows: typical steppe grassland dominanted the baseband of the mountain; Prunus mongolica thickets, Pinus tabulaeformis + Ulmus glaucescens + Platycladus orientalis sparse forest, Prunus pedunculata thickets, Stipa krylouii communities occupied in sequence on the sunny slope; Prunus mongolica thickets, Prunus pedunculata thickets, Pinus tabulaeformis forest, Betula platyphylla forest appeared regularly on the shady slope; (2) from grassland to forest, the diversity of communities and species diversity were significantly increased; (3)there was close relationship between slope and vegetation distribution. Moisture, soil conditions in shady slopes were good, mainly in the development of plant community with mesophyte as constructive species, such as, Betula platyphylla, Pinus tabulaeformis. The main vegetations, shrub and grass, were drought-resistant with the conditions of great soil evaporation, poverty soil in sunny slope, such as, Prunus pedunculata, Prunus mangolica and Rosa xanthina; (4) slope gradients also influenced strongly on distribution in the mountain. Different vegetation types were suitable to different slope gradients, all types can be observed under 45°, and when slope was above 45°, vegetation types were obviously disappeared.