环渤海地区生态脆弱性评价及其空间自相关分析

Ecological Vulnerability Assessment and Spatial Auto-Correlation Analysis over the Bohai Rim Region

基于生态敏感性-生态恢复力-生态压力度概念框架,建立了环渤海地区五省市生态脆弱性评价的指标体系。考虑到指标体系中各评价因子之间可能存在相关性,所以首先在ArcGIS9.2平台上,用主成分分析方法剔除各因子的相关性,并对该区的生态脆弱性进行了评价,然后对脆弱性进行了空间自相关分析。结果表明:生态环境好的、相对不脆弱区主要分布在低山、丘陵等植被状况好、人类活动少的地区;重脆弱区主要分布在农牧交错带、海陆过渡带和城市周围等生态系统不稳定、人类活动剧烈的地区;脆弱区的空间聚集程度呈现出较高的正相关;不同地区之间脆弱性高相关区域主要分布在南部的低脆弱地区,脆弱性低相关区域主要分布在西北部的重脆弱区。

The Bohai Rim area is not only the region of significant economic growth in China, but also the region of a variety of ecosystems. To this end, it is important to evaluate eco-environmental vulnerability for regional development and eco-environment construction and protection. The study region covers the Bohai Rim consisting of Beijing and Tianjin Cities, and Liaoning, Hebei and Shandong Provinces. There are different types of ecological divisions across the regions, for example, the coniferous broad-leaved mixed forests zone, the agro-ecological zone, the deciduous broad-leaved forests zone, the agriculture-pasture transition zone, and the sea-land interaction zone. Based on the conceptual framework of ecological sensitivity-resilience-pressure, the authors developed an evaluation indicator system for the study region. The sensitivity indicators embody topography, shallow ground, atmosphere and hazards; the resilience indicator was characterized by the net primary productivity （NPP） of vegetation, and the pressure indicators comprise human activities and economic activities. Because of the correlations among different indicators, it was necessary to remove the correlations by means of the principal component analysis （PCA）. The authors obtained four principal components using ArcGIS 9.2 software packages. Subsequently, based on the derived principal components and their eigenvalues, the authors quantified and analyzed in detail the vulnerability over the region. Then, the spatial auto-correlation analysis commonly used in the area of economic geography was performed. The results indicated that 1） the non-vulnerability regions includes the coniferous broad-leaved mixed forests regions in Changbai Mountain areas, the deciduous broad-leaved forests regions in Yanshan and Taihang Mountains areas, the deciduous broad-leaved forests regions in Shandong Peninsula and the deciduous broad-leaved forests regions in rolling terrain of the south of Shandong Province; 2） The vulnerability regions encompass the agriculture-pasture transition zones of the northwest of Hebei, the sea-land interaction zones of the Bohai Rim; 3） The spatial patterns of ecological vulnerability exhibit that the non-vulnerability areas primarily located in the mountains and hills with less human activities where the status of vegetation maintains well whereas the vulnerability areas are primarily distributed across the interaction zones, transitional zones and urban fringe areas where the ecosystems are instability and with intense human activities; 4） The vulnerability of the study area shows a relatively high degree of positive correlation and the high correlation areas are mainly distributed in the south of non-vulnerability regions. The low correlation areas are primarily distributed over the northwest of the high vulnerability regions.