Valuing The Soil Ecosystem Services Of The Different Land-use Types In The Upper Reaches Of The Minjiang River

Being one of the most effective ways to awaken humankind's understanding of nature value, to increase humankind's investment in environmental protection and to promote harmonious development of humankind, research of ecosystem services value has attracted great attention of the scientists. As the most active sub-system among the terrestrial ecosystem, soil is the kernel of ecosystem service value research thanks to its strong ecological service function. Even though the soil ecosystem at the upper reaches of Minjiang River is very much important and sensitive in ecological term, overall evaluation coverage about its ecological value is not so much so that it is pretty difficult to meet the demand of building a reasonable ecological compensation mechanism for this district. Therefore, on basis of full knowledge about the land use types at the upper reaches of Minjiang River, this article selects out nine typical land-use types (Spruce-fir natural forestland (SFNF), Spruce-fir artificial forestland (SFAF), Birch forestland (BF), Silver Chain artificial forestland (SCAF), Economic forestland (EF), Shrubbery land (SL), Coniferous- deciduous mixed forestland (CBMF), Grassland (GL), Farmland (FL)) as the research objects and is to establish a value evaluation system for its soil ecosystem service value through comparative study of ecosystem service function and its value evaluation system at home and abroad. Besides, with combination of field investigation and sample analysis, this article, by using of value evaluation methods in ecological economics, presents a preliminary value accounting about the soil ecosystem at the upper reaches of Minjiang River in terms of water conservation, carbon fixation, soil conservation and biodiversity conservation in 2005. Its aim is to provide the basis for objective evaluation of the ecological assets at the upper reaches of Minjiang River, to build a sound ecological compensation mechanism, and to formulate practical resource development strategy and management tactic of ecosystem adaptability, which has great significance to promote ecological environmental protection and to realize the social value, economic value as well as ecological value of ecosystems and thus to maintain sustainable development of this district. The result shows that:(1) The soil ecosystem at the upper reaches of Minjiang River in 2005 contained tremendous ecological value—about 327.11×10~8 yuan, equivalent to 9.50 times of the GDP value 34.42×10~8 yuan in the same year in this district among which the ecological value of water conservation, carbon sequestration, soil conservation and biodiversity conservation was 3.74×10~8, 223.23×10~8, 17.12×10~8 yuan and 83.02×10~8 yuan respectively, accounting for 1.14%, 68.24%, 5.23% and 25.38% of the total value respectively.(2) The acreage of different land use types at the upper reaches of Minjiang River varies too much and thus it becomes the decisive factor for the soil ecological value under different land use types. The result shows that GL, NSF, and SL are the main contributors to the soil ecosystem services function in this district.(3) As natural and man-made factors have different effects on soil ecosystem, ordering of ecosystem service value in unit area under different land-use types varies too much, for example, in terms of water conservation, the ordering is SFNF > BF > CBMF > SFAF > SCAF > EF > SL > GL>FL while in terms of carbon sequestration, the ordering is SFNF > GL > SL> BF> SFAF >EF> CBMF > SCAF > FL and in terms of soil conservation, the ordering is CBMF > BF > GL > SCAF > SL> EF > SFAF > SFNF > FL.