三峡库区土壤保持重要区生态敏感性空间特征

Spatial Difference of Eco-environmental Sensitivity of Three Gorges Reservoir Soil Conservation Area in Chongqing

借助遥感数据和GIS空间分析,选取生境、酸雨、土壤侵蚀和石漠化4种生态环境敏感要素建立空间评估模型,综合分析了受"自然-人工"二元干扰严重的三峡库区土壤保持重要区(重庆段)生态环境敏感性程度及其空间分异特征。结果表明:(1)研究区生境敏感性主要以不敏感和高度敏感为主,高度以上敏感性区域主要分布在巫溪北部大巴山、奉节南部七曜山、石柱方斗山、江津南部西面山和都市区"四山"。(2)酸雨敏感性总体较高,高度敏感性面积和占比分别达到了18 609.85 km^2和40.30%,空间上以武隆-丰都-忠县-开州为界,西部主要以高度敏感性分布为主,东部主要以中度敏感性分布为主,轻度敏感性和不敏感性则主要在江河沿岸呈带状分布。(3)土壤侵蚀敏感性不容乐观,极度敏感性、高度敏感性和中度敏感性面积占比之和超过了80%,尤其是东北部开州、云阳、奉节、万州、巫溪、巫山等区域,土壤侵蚀敏感性均较高。(4)石漠化以不敏感性为主,面积达27 808.57 km^2,占总面积的60.22%,东北部巫溪、开州、巫山和奉节境内局部地区有少量极敏感性分布。(5)研究区生态环境敏感性总体程度较高,中度以上敏感性比例超过了70%,高度以上敏感性比例接近50%,空间上东北部地区和东南部地区生态环境敏感性明显高于其他地区,尤其是巫溪北部大巴山,开州北部雪宝山,奉节南部、石柱南部七曜山,丰都东南部和武隆南部,生态环境敏感性均较高。

A space evaluation model was developed by means of remote sensing data and the GIS spatial analysis,which involved four factors of eco-environmental sensitivity,i.e.,bio-inhabitation,acid precipitation,soil erosion and rocky desertification.The model was used to analyze,in a comprehensive way,the eco-environmental sensitivity and the relevant spatial variation character in the important soil conservation area（within Chongqing City）of the Three Gorges Reservoir Region.The analysis indicated：（1）insensitivity and hypersensitivity are two main types in terms of bio-inhabitation sensitivity in the study area,and the Daba Mountain,Qiyao Mountain,Fangdou Mountain and Simian Mountain,as well as the metropolitan＂Four Mountains＂were the most sensitive areas;（2）the sensitivity of acid precipitation as a whole was high,the acid-rain area being18 609.85 km2,approximately 40.30%of the whole study area,as to the geographical distribution,west of the Wulong,Fengdu,Zhongxian,Kaizhou was relatively higher than the east,and the areas of mild sensitivity and insensitivity mainly situated along the Yangtze River coast;（3）the condition in terms of soil erosion sensitivity was not optimistic：the areas of hypersensitivity-high sensitivity and medium sensitivity regions accounted for more than 80%of the whole study area,especially in the areas characterized with intensive soil erosion sensitivity including the counties of Kaizhou,Yunyang,Fengjie,Wanzhou,Wuxi and Wushan;（4）regions of karst rocky desertification mainly belonged to insensitivity with an area of 27 808.57 km^2,accounting for 60.22%of the whole study area;（5）the area proportions of the above-medium sensitivity and the above-high sensitivity were more than 70%and about 50%,respectively,so in general the eco-environmental sensitivity of the study area was relatively high.With regard to geographical distribution,the northeastern and southeastern parts of the study area had higher eco-environment sensitivity than other areas,especially in the Daba Mountain,Xuebao Mountain and Qiyao Mountain,as well as southeast Fengdu and the south part of Wulong.