Impacts of land use and land cover changes upon oxygen regulation values for the Karst Ecosystem: a case study of Northwest Guangxi, China

The poverty and environmental degradation are very serious in karst regions of southwest China. In this paper, the spatial distributions and variations of oxygen regulation values (ORVs) were evaluated for the typical karst areas in Northwest Guangxi, China from 1985 to 2005, based on remote sensing and geographic information system techniques. The results showed that ORVs decreased firstly and then increased. ORVs were 9170 million Yuan in 1985, 5831 million Yuan in 1990, 7802 million Yuan in 2000 and 8793 million Yuan in 2005, respectively. Woodland and shrub were the two largest contributors to total ORVs (70.51% in 1985, 69.13% in 1990, 73.35% in 2000 and 66.23% in 2005). ORVs declined from west to east, and in creased from 4338 million Yuan in 1985 to 4780 million Yuan in 2005 in the typical karst areas. This indicates that ecosystem conditions are improving because of the application of rocky desertification control policies.