基于土地利用格局重建的区域生境质量时空变化分析

区域生境质量决定了区域内生物多样性状况,是生态系统服务功能和生态系统健康程度的重要体现,生境质量变化研究对区域生态安全具有重要的意义,重建区域生境质量空间格局可以还原历史时期的生态环境本底,为揭示区域生态环境质量演变规律提供科学支撑。选取高程、坡度、坡向、GDP、人口、温度、降雨量、河流距离、城市距离和海岸线距离10个土地利用变化驱动因子,构建CA-Markov模型参数,模拟得到历史土地利用空间数据。在此基础上,运用InVEST模型重建泛长三角地区生境质量空间格局,并对计算得到的生境退化度指数和生境质量指数进行等级划分与统计分析。结果表明：① 土地利用模拟精度验证结果显示Kappa系数为0.88,土地利用空间格局重建方法可行,可以在此基础上开展生境质量模拟研究。② 泛长三角地区1975—2010年生境退化度逐期上升,生境退化等级在空间分布上呈圈层递变分布规律。生境质量则表现为逐期下降,高值区主要分布于山区,低值区大部分位于建成区;1975—2010年期间,低值区逐渐向周边高值区域演变,生境高值区域趋于破碎化。③ 1975—2010年生境质量时空变化特征表明：生境质量差等级区域,其生境难以修复,维持原状居多;生境质量较差等级区域易继续恶化,且易发生在建成区周边区域,占比为研究区总面积的6.40%;生境等级为良好和优等的区域,其生境等级易转换为差等和较差等级,使得该区域的生境破碎化,该类型的面积占比为研究区总面积的5.68%。④ 1975—2010年期间,研究区土地利用变化显著,对生境质量造成了巨大的影响;研究区生境质量逐期变差,其生境质量等级位于较差及以下区域面积占比均达到了60%以上,建设用地为生境质量最大的威胁因子。

Analysis on spatial and temporal changes of regional habitat quality based on the spatial pattern reconstruction of land use

Habitat quality determines the status of regional biodiversity which is an important reflection of ecosystem service function and health. Research on the habitat quality change is of great significance for regional ecological security. The reconstruction of regional spatial pattern of habitat quality can restore the background of ecological environment in historical periods and provide scientific support for revealing the evolution law of regional ecological environment quality. This study selected ten driving factors (elevation, slope, aspect, GDP, population, temperature, rainfall, river distance, urban distance and coastline distance) to build CA-Markov model parameters and simulate the historical land use data. The spatial pattern of habitat quality was rebuilt by InVEST model, and the classification and statistics of habitat degradation and habitat quality were examined. The results showed that: (1) The Kappa coefficient is 0.88, which proves that the land use spatial pattern reconstruction method is feasible. On this basis, the simulation of habitat quality is valid. (2) During 1975-2010, the degree of habitat degradation increased gradually and the spatial distribution of it showed a regular pattern of circle layer change. The habitat quality decreased steadily. The high-value areas were mainly distributed in mountainous areas, while the low-value areas were mostly distributed across built-up areas. In this period, the low-value areas gradually engulfed the high-value areas around, and the habitats of the high-value areas tended to be fragmented. (3) In 1975-2010, the spatio-temporal variations of habitat quality indicated that the region with the worst habitat quality were difficult to recover; the regions with the poor habitat quality accounted for 6.40% of the total area, which were prone to deteriorate and occur around the built-up areas; the areas with the best or better habitat quality grades accounted for 5.68% of the total area, which could be easily transformed into the poor and worst habitat grades, making the habitat more scattered. (4) There was a marked change with land use of study areas during 1975-2010, which had a huge impact on the quality of the habitat. The above results show that the habitat quality of the study area decreases gradually. More than 60% of the regions have poor or even worst habitat quality. Construction land is the biggest factor threatening the habitat quality.