Land use and land cover change on slope in Qiandongnan prefecture of Southwest China

Abstract

This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou province, China. The land use data were classified into five types, forest, farmland, grassland, water and built-up, the slope gradients were divided into four grades. Indices for analyzing land use features were defined by their proportions, transformation matrixes, land use degree and changes. The results showed that all land use types can be found at every gradient. Generally, with the slope degree increased, the area of forest being augmented as well, while the area of the other land use types (farmland, grassland and build-up) declined. Moreover, a mass of farmland were shifted from other land use types from 0° to 25°, while a quantity of forest were transformed from the other land use types on >25° from 1993 to 2009. In terms of land use degree and changes, the area of farmland and buildup land use types decreased when slope degree increased. Finally, we calculated the five landscape pattern metrics: Patch Density (PD) value, Largest Patch Index (LPI), Shannon’s Diversity Index (SHDI), Area-Weighted Mean Shape Index (AWMSI) and Contagion Index (CONTAG). The results of metrics analysis showed that PD values, SHDI values and CONTA values had a similar variation trend, that is, they decreased when slope degree increased. There was no obvious variation trend on LPI value.