“省公顷”生态足迹模型中均衡因子及产量因子的计算--以浙江省为例

Calculation and Analysis of Equivalence Factor and Yield Factor of Ecological Footprint Based on Sub-national Hectare:A Case Study of Zhejiang

生态足迹模型是分析人类对自然资本的需求和自然资本的供给情况的有力工具。为更加准确地核算中小尺度的生态足迹,论文建立了"省公顷"模型,明确了均衡因子和产量因子的含义与计算方法。在计算方法上,首次引入热值的概念,克服了不同类型生物产品不能直接加总的难题。以浙江省为例,应用本方法测算了2005年各类土地的均衡因子和各市土地的产量因子。其均衡因子分别是:耕地为2.82 s-nhm2/hm2;草地为0.11 s-nhm2/hm2;林地为0.35 s-nhm2/hm2;水域为0.17 s-nhm2/hm2等。结果与国际上通行的数值和国家公顷下的数值存在较大差异,但通过分析认为,文章的均衡因子和产量因子客观地表达了浙江省的实际情况,存在差异是合理的。最后,指出文章所构建的方法简单易行,结果合理,该计算方法可推广到国家层面;在进行省域层面的生态足迹分析时,模型应采用"省公顷"对应的均衡因子和产量因子,以使分析更加具有实际意义。

Ecological footprint provides a big picture analysis to compare human demands on natural capital with the ability of supply of natural capital. But the conventional ecological footprint analysis which is based on global hectare could not well and truly calculate the eco-footprints of middle and small spatial scale, such as national or sub-national scale. Because of the diversity which exists in the productivity among land of different provinces and different counties in a province, at national or sub-national scale, equivalence factor and yield factor that complexly show territorial natural condition and socioeconomic circumstance can deliver apparent differences in a certain year. Ecological footprint analysis based on sub-national hectare was established in this article. Based on the ＂sub-national hectare＂ framework, this paper addresses two conceptual issues that determine model design： the specific meaning and measurement of equivalence factor and yield factor. To overcome obstacle that biomass yielded different lands can not be added directly, caloric value embodied in unit biomass was innovatively introduced to calculate equivalence factors and yield factors. Equivalence factors and yield factors of biologically productive land and water in the year 2005, using the example of Zhejiang province, were calculated through this method. According to the calculation results, the equivalence factors of Zhejiang of 2005 were that： cropland was 2.82s-nha/ha; pasture was 0.11s-nha/ha; forest was 0. 35s-nha/ha; fishery water was 0. 17s-nha/ha and so on. Yield factors of counties in the Zhejiang province were different to each other, e.g. , cropland yield factor changed from 0. 66 in Zhoushan to 1.73 in Jiaxing; pasture yield factor changed from 0. 12 in Zhoushan to 8. 57 in Jiaxing; forest yield factor changed from 0. 02 in Zhoushan to 2. 81 in Huzhou; fishery yield factor changed from 0. 31 in Zhoushan to 2. 84 in Jiaxing, which indicate the diversity of the productivity among land of different counties in a province. The results gained from ＂sub-national hectare＂ framework, differed from figures which universally prevail in ＂global hectare＂ and measure in ＂national hectare＂. Through the analysis of that on detail, it recognized that values of equivalence factors and yield factors achieved in this paper delivered the actual circumstances of Zhejiang province. As a result, this method can now demonstrate a simple and valid process to achieve a clear and factual result, and can be generalized to analyze the national eco-footprints; equivalence factors and yield factors corresponded to sub-national hectare should be used to analyze ecological footprint and biological capacity at sub-national scale.