2000-2020年漓江流域景观生态脆弱性时空分异

漓江流域是我国南方脆弱岩溶环境的重要生态安全屏障。通过景观生态脆弱性评价优化国土空间治理,可为岩溶区生态修复和脱贫攻坚成果提供科学依据。基于土地利用、遥感信息和GIS空间分析平台,应用景观指数、时空统计、空间分析、地理探测等方法,从多维时空尺度分析了漓江流域景观生态脆弱性及其时空变化规律。结果表明:(1)漓江流域以林地、耕地为主体景观,面积占全流域的90%,近20年其变率小于0.37%,扩张强度小于3.59%,流域景观格局稳定; 建设用地增长最快,扩张强度高达72.97%,动态度明显高于其他地类,城镇化进程是景观格局的主要驱动因素;(2)景观生态系统以中低级脆弱区为主,占总面积的56.53%,高危脆弱区面积占比小于10%; 形成城镇化中心低值聚集,山地区高值连片的分异格局; 近20年一级、五级脆弱区扩张强度分别为1.70%,1.36%,中高级脆弱区面积扩张强度-2.59%,流域景观生态脆弱性减弱。(3)LEV空间分异呈现人工景观低值化与自然景观高值化格局。桂林市区是低—低相邻的冷点,周边山区为高—高相邻的热点,近20年冷点、热点范围都略有扩大,景观生态脆弱性与城镇化有显著的正向空间依赖性。(4)城镇化及坡度变化对脆弱性的解释度最大,其q值分别为0.2689,0.250 8,是LEV空间分异的核心驱动,自然和人工因素共同决定了LEV时空分异。漓江流域土地利用应坚持综合治理和系统规划的原则,统筹城乡土地利用和国土空间规划,系统融合城市与乡村、自然与人工景观类型及功能。

Spatiotemporal Differentiation of Landscape Ecological Vulnerability in Lijiang River Basin from 2000 to 2020

The Lijiang River Basin is an important ecological security barrier for the fragile karst environment in southern China. Optimizing the land space management through the assessment of landscape ecological vulnerability can provide a scientific basis for the ecological restoration and poverty alleviation achievements in karst areas. Based on land use, remote sensing information and GIS spatial analysis platform, landscape ecological vulnerability and temporal-spatial changes of landscape index of the Lijiang River Basin were analyzed from multi-dimensional temporal-spatial scales with the methods of landscape index, temporal-spatial statistics, spatial analysis, geodetector employed. The results indicate that the main landscape of the Lijiang River Basin is forestland and cultivated land, accounting for 90% of the total basin area; in the past 20 years, its area change rate was less than 0.37%, the expansion intensity was less than 3.59%, and the basin landscape pattern was stable; construction land had the fastest growth and significant expansion, its dynamic degree was significantly higher than other land type and the urbanization process was the main driver of the landscape pattern; the landscape ecosystem was dominated by low-and middle-level fragile areas, accounting for 56.53% of the total area, and high-risk fragile areas accounting for less than 10%, which formed a differentiation pattern of low-value clusters in urbanization centers and high-value contiguous mountain areas; in the past 20 years, the expansion intensities of level 1 and level 5 vulnerable zones were 1.70% and 1.36%, respectively, and the area expansion intensity of middle and high-level fragile areas was -2.59%, informing that the ecological fragility of the basin landscape weakened; the landscape ecosystem was dominated by low-and middle-level fragile areas, and the area of high-risk fragile areas accounted for less than 10%; a differentiation pattern of low-value clusters in urbanization centers and high-value contiguous mountain areas had been formed; In the past 20 years, the range of low-value areas had continued to expand while the area of middle and high-level fragile areas reduced, informing that the ecological fragility of the basin landscape weakened; LEV spatial differentiation presented a pattern of low-value artificial landscapes and high-value natural landscapes; the urban area of Guilin was a low-low adjacent cold spot, and the surrounding mountainous area was a high-high adjacent hot spot; the range of cold spots and hot spots had expanded slightly in the past 20 years, and the landscape ecological spatial pattern was relatively stable; urbanization and gradient changes had the greatest degree of explanation for vulnerability, with q values of 0.268 9 and 0.250 8, respectively, which were the core drivers of LEV spatial differentiation; natural and artificial factors jointly determined LEV temporal and spatial differentiation. The land use of the Lijiang River Basin should adhere to the principles of comprehensive management and systematic planning, coordinate urban and rural land use and land space planning, and systematically integrate the types and functions of urban and rural, natural and artificial landscapes.