基于连通度指数的生态安全格局构建——以三峡库区重庆段为例

生态安全格局构建旨在识别研究区的重要生态区域并保持他们之间连通,被认为是实现区域协调发展的重要途径。生态阻力面的科学构建和修正一直是生态安全格局建立的技术难点。以三峡库区重庆段为例,通过生态重要性和敏感性综合识别源地,构建连通度指数修正阻力面,利用最小累积阻力模型提取生态廊道,从而构建三峡库区重庆段生态安全格局。结果表明:(1)研究区生态源地面积19227.04 km²,占总面积41.65%,主要集中在东北部和中东部的林地。(2)相较于夜间灯光指数,连通度指数在景观破碎地区和人类活动强烈地区对阻力面修正更加明显,一定程度也可反映人类活动的影响。(3)研究区生态廊道总长度1610.48 km,包括天然廊道和阻力廊道;战略点30个,主要位于耕地、居民点和水域附近。(4)研究区生态连通性较好,但部分地区存在廊道缺失、战略点阻断的现象。

Establishment of an ecological security pattern based on connectivity index: a case study of the Three Gorges Reservoir Area in Chongqing

Construction of ecological security pattern aims to identify important ecological regions of the study area and maintain their interconnection. It is considered as an important way to achieve the coordinated development at the regional scale. There are some technical difficulties to build ecological resistance surface in the construction of ecological security pattern. This paper took the Three Gorges Reservoir Area in Chongqing section (TGRAC) as a case study. Based on GIS, ecological sources were identified in terms of ecosystem services'' importance and ecological sensitivity. The ecological corridors were identified through using minimum cumulative resistance model. The results showed as follows: (1) the area of ecological source was 19227.04 km², which accounted for 41.65% of the total area of the TGRAC. The ecological source area was mainly composed of forest land in the northeast and central part of the study area. (2) Compared with the night light index, the connectivity index corrected the resistance surface more obviously in the fragmented landscape areas and areas with strong human activities, and could also reflect the impacts of human activities to a certain extent. It showed that the connectivity index could modify the ecological resistance surface, and its correction effect was better than that of the night light index. (3) The total length of ecological corridors network in TGRAC was 1610.48 km, including natural corridors and resistance corridors. There were 30 strategic points, mainly located near cultivated land, residential areas, and waters. (4) The ecological connectivity of the study area was well, and it generally formed a spatial pattern of "one axis, three zones". However, corridors and blockage of strategic points were lack in some areas. Therefore, this paper proposed a restoration scheme to ensure the integrity of the ecological network in the study area.