Assessment of Service Value of Ecosystem in Karst Ecological Control Areas

To investigate the characteristics of service value of the karst rocky desertification ecosystem, we take water conservation, soil conservation, carbon-fixation and oxygen-production, production of organic matter, and purification of atmospheric environment as function indicators, to conduct quantitative assessment and analysis of service function value of ecosystem in Yachi Town, Bijie City; Hongfenghu Town, Qingzhen City; Guanling-Zhenfeng Huajiang Demonstration Area in Guizhou Province, using remote sensing and field monitoring data in 2006. The results show that the rate of contribution of water conservation, soil conservation, carbon-fixation and oxygen-production functions to regional service value is high (37.05%, 36.68% and 23.15%, respectively); the rate of contribution of production of organic matter and purification of atmospheric environment functions to regional service value is low (2.80% and 0.32%, respectively). The ranking of landscape in terms of service value per unit area is as follows: forestland (23.3539 million yuan)> shrub land (10.6301 million yuan)> grassland (5.0367 million yuan)>dry land (3.3812 million yuan)> farmland (2.5088 million yuan). The ranking of demonstration areas in terms of service value per unit area is as follows: Yachi Demonstration Area (12.44 million yuan)> Hongfenghu Demonstration Area (5.91 million yuan)> Huajiang Demonstration Area (4.4 million yuan). It is negatively correlated with rocky desertification incidence within the region. The results also indicate that in the process of restoring and reconstructing the ecological environment in rocky desertification areas, increasing the area of forest vegetation, promoting the conversion of dry land and farmland into forestland, shrub land and grassland, will contribute to enhancement in ecological service value.