山水林田湖草生态问题系统诊断与保护修复综合分区研究——以陕西省为例

Systematic diagnosis of ecological problems and comprehensive zoning of ecological conservation and restoration for an integrated ecosystem of mountains-rivers-forests-farmlands-lakes-grasslands in Shaanxi Province

山水林田湖草生态保护修复分区的划定,是科学合理的分区域提出生态保护修复方案的基础。但是,目前生态保护修复分区的划定,对于生态系统问题诊断的综合性考虑不足,未能很好的体现山水林田湖草生命共同体的理念。因此,选取了8个指标综合考察了陕西省的山水林田湖草生态系统问题,并以小流域为基本单元,划定了陕西省山水林田湖草生态保护修复综合分区。研究表明:(1)2015年陕西省生态修复指数平均值为0.39(该值越小表明山水林田湖草人的综合问题越严重),各流域生态修复指数在0.23-0.60之间。总体来看,陕西省生态修复指数的空间分异较为明显,呈现自南向北逐渐递减的格局。(2)划分了8个生态保护修复分区,包括陕南秦岭东部地区、关中平原中部的城镇地区、汉江河谷盆地、陕北黄土高原中南部地区、陕南秦岭山区、陕北黄土高原北部地区、关中平原地区和陕南大巴山地区。在生态系统问题综合诊断方面,水土流失、植被退化、降水资源不足是陕北黄土高原地区主要生态问题;南部秦巴山区的生态系统则易受到极端降水和土壤侵蚀的影响;关中平原主要存在林草植被退化、矿产资源开采强度大和水土流失等生态问题。

Delineation of the ecological protection and restoration zones from a perspective of an integrated ecosystem(including mountains-rivers-forests-farmlands-lakes-grasslands) is the basis for bringing forward a scientific and rationally proposal to protect and restore ecosystems. However, the current delineation is relatively insufficient for the comprehensive consideration of ecological problems, and it does not reflect the concept that mountains-rivers-forests-farmlands-lakes-grasslands are a shared community. In this paper, taking Shaanxi Province as a study region, we selected 8 indicators to systematically diagnose its ecological problems. On this basis, we delineated the ecological protection and restoration zones at small-watershed scale. The results showed that:(1) the average value of ecological restoration index(ERI) of Shaanxi Province in 2015 was 0.39(the smaller the value was, the more serious ecological issues that needed to be remedied), and the ERIs of different small watersheds ranged from 0.23 to 0.60. In general, the spatial heterogeneity of ERI in Shaanxi Province was obvious, and it tended to decrease from south to north.(2) There were 8 ecological restoration zones, including the eastern part of the Qinling Mountains in southern Shaanxi, the urban areas in the central of the Guanzhong Plain, the Hanjiang River Valley Basin, the central and southern parts of the Loess Plateau in northern Shaanxi, the Qinling Mountains in the southern Shaanxi, the northern part of the Loess Plateau in northern Shaanxi, Guanzhong Plain area, and Daba Mountain area in southern Shaanxi. Soil erosion, vegetation degradation, and insufficient water resources were the main ecological problems in the Loess Plateau, while the ecological environment in Qinba Mountains area was susceptible to extreme precipitation and soil erosion. For the Guanzhong Plain, ecological problems were vegetation degradation, intensive exploitation of mineral resources, and soil erosion.