Ecosystem service values have been improved as a result of the implementation of rocky desertification control policies in karst areas of northwest Guangxi.

Ecosystem services are the conditions and processes through which natural ecosystems and species that comprise them, sustain and fulfill human life. They can also be described as goods and services provided by the ecosystem which contribute to human welfare directly or indirectly. With current issues of resources depletion, environmental degradation and ever increasing human population, it is urgent to evaluate ecosystem conditions and services values.

Hence, a team of researchers, led by WANG Kelin, at the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) has spent 15 years to monitor the karst ecosystem condition in karst region of northwest Guangxi and to determine how this karst ecosystem provides goods and services for human society.

"Using remote sensing, geographic information systems and statistical techniques, we analyze the spatiotemporal variation of ecosystem service values (ESVs) and its correlation with numerous environmental factors (EFs) in this karst region from 1985 to 2005.” said researcher ZHANG Mingyang. “The results we found indicate that historically ESVs for this karst region decreased from 1985 (1096.52 million Yuan) to 1990 (887.89 million Yuan) and then increased at the turn of the 21st century.”

However, researchers found the ESVs in both 2000 (1033.84 million Yuan) and 2005 (1062.57 million Yuan) never achieved the level recorded in 1985. The total of nutrient cycling, organic production and gas regulation combined were 72.69%, 64.57%, 70.18% and 72.10% of ESVs in 1985, 1990, 2000 and 2005, respectively. In contrast, the ESVs of water conservation, soil reservation, recreation and culture were determined to be relatively low contributing only 17.44%, 23.82%, 19.26% and 24.76% of total ESVs, respectively, during these four years. With regards to the spatial distribution of ESVs, larger values were recorded in the west and smaller ones recorded in the east. The most significant factors that were deemed to influence ESVs are annual rainfall, per capita cropland, slope and vegetation coverage. Annual rainfall and slope exert a negative force, whereas per capita cropland and vegetation coverage exert a positive force on ESVs. The results of the study would suggest that ecosystem conditions of this important karst region have been improved as the result of the implementation of rocky desertification control policies.

This study was supported by the Chinese Academy of Sciences Action Plan for the Development of Western China (KZCX2-XB3-10), National Natural Science Foundation of China (31000223, 41071340), the Western Light Program of Talent Cultivation of the Chinese Academy of Sciences, the Knowledge Innovation Program of the Chinese Academy of Sciences (ISACXLYQY-QN-1102).

The study entitled “Spatiotemporal Variation of Karst Ecosystem Service Values and Its Correlation with Environmental Factors in Northwest Guangxi, China” has been published in the November journal of Environmental Management, details could be found at http://www.springerlink.com/content/a803630602565t15/.