生态重建模式的评价方法——以黄土丘陵区为例

The Evaluating Method of Eco-environment Restoration Patterns:A Case Study of the Loess Hilly-gully Region

生态重建模式是协调生态脆弱地区人地关系的系列政策和配套措施的总称。作者在按模式总体特征、生态重建规模、投资需求及实施效果开展评价方法讨论和筛选评价指标的基础上,以黄土丘陵区为例,总结了“赈济退耕”、“梯田退耕”和“坝系根治”3种模式的基本特征,计算了不同模式下黄土丘陵区生态重建关于退耕、新修梯田、园地扩建、建坝淤地以及林草植被恢复等的规模和投资需求额度,分析了各模式下的生态重建效益。结果表明:“梯田退耕”可作为黄土丘陵区生态重建的主体模式,目前正在实施的“赈济退耕”具有显著的过渡性特征,“坝系根治”在局部区域可作为辅助模式。

The eco-environment restoration pattern means an integration of the policies and their matching measures in regulating the relation between human being and environment in the eco-environmentally fragile areas. This paper discussed the contents, indices and methods of the pattern evaluation. And then, based on the research results in the past ten years and the successful cases of small watersheds in the loess hilly-gully region, the characteristics of eco-environment restoration patterns including 'relieving and de-farming' (RD), 'rebuilding terrace and de-farming' (RTD) and 'dam system and permanent control' (DSPC) were summarized. The sizes of de-farming slope farmland, rebuilding terrace, enlarging garden plot and restoring vegetation were calculated, the investment demands of eco-environment restoration on three patterns were done, benefits from those patterns were analyzed respectively and compared among each other. As a result, this paper drew the following conclusions:(1) RD pattern showed that the area of de-farming slope farmland more than 25o is 41.91×104 hm2 with 44.01×108 yuan (RMB) of policy allowance, and that of de-farming slope farmland more than 15o is 125.53×104 hm2 with 131.82×108 yuan of that. The result of RTD pattern is that the area of enlarged terraces is 69.16×104 hm2 and that of restored vegetation is 541.02×104 hm2, with 125.05×108 yuan of total investment demand. And the data from DSPC pattern included 36×104 silt-covered dams, 55.98×104 hm2 of silt-covered farmland and 554.2×104 hm2 of new woodland or grassplot, and 221.22×108 yuan of investment demand.(2) The benefit analysis of three patterns and their comparison results showed that RTD pattern ranks the first, with appropriate investment demand, better benefit and safer food supplies. Compared with RTD, RD being underway at present is a transitional pattern, with lower benefit and unsafe food supplies, and it should be replaced with RTD as soon as possible. On account of the limitation of its bigger investment demand and more uncertain factors, DSPC can be only regarded as an accessorial pattern, in despite of its profit prior to that of RTD.