CACE模型及其在生态安全格局优化中的应用

中国城镇化进程的快速推进,使得各种建设活动对土地资源的需求日益增加,引发一系列生态环境问题,特别是在生态脆弱区,土地资源不合理的开发利用加剧了区域生态安全风险。因此,为探究区域生态安全格局优化的途径方法,保障区域生态安全和土地资源合理利用,该研究通过解译判读怀来县1993年、2003年和2013年3期遥感影像,运用土地利用变化信息图谱及构建建设用地和生态用地竞争优势模型,分析了怀来县土地利用变化热点区域及建设用地与生态用地竞争优势分布区,划分了建设用地与生态用地优势分布临界线,同时,基于景观生态学理论,构建了怀来县综合生态安全格局,并将建设用地与生态用地竞争优势分布区应用于生态安全格局优化。结果表明:怀来县综合生态安全格局面积为1 470.59 km2,占怀来县总面积的82.51%,基本安全格局分布在临界线外围,满意安全格局外围主要沿临界线分布、理想安全格局主要分布在临界线内部。基本生态安全格局受到建设用地扩张的压力相对较小,满意生态安全格局主要位于生态优势区,在一定程度可以起到对建设用地扩张的限制作用,作为怀来县重要的生态缓冲区,理想安全格局受到建设用地扩张的压力较大,其内部应注重生态廊道网络建设,引导自然斑块以廊道或小型斑块的形式分散地融入建设用地中。研究方法和结果可以为区域生态规划和城乡布局等提供决策参考。

CACE model and its application in optimization of ecological security pattern

The rapid urbanization in China has caused a series of ecological and environmental problems. The irrational utilization of land resource poses the risk of regional ecological security, especially in ecological fragile regions. Consequently, the study on the optimization of ecological security pattern is essential to the regional ecoplanning and optimal allocation of land resources, and beneficial to the sustainable development. In order to explore the ways of optimizing regional ecological security pattern and ensuring regional ecological safety and rational utilization of land resources, this study was conducted in Huailai County located between 115°16′-115°58′E and 40°04′-40°35′N. By interpreting the remote sensing images of 1993, 2003 and 2013, the study analyzed the hot regions of land use change in Huailai county through the information map spectrum of land use change and by establishing Competitive Advantage of Construction Land and Ecological Land (CACE) Model. The study also analyzed the competitive advantage distribution area and divided the competition critical line of construction land and ecological land. In view of landscape ecology, the study constructed the single factor ecological security pattern of hydrology, geological hazard prevention, biodiversity conservation and soil and water conservation respectively. The maximum value of each single factor was utilized to construct the regional comprehensive ecological security pattern. The optimization direction of ecological security pattern was proposed according to the distribution of dominant region of construction land and ecological land. The results showed that: 1) the hot regions of land use change in Huailai County mainly appeared around Guanting Reservoir and Shacheng Town as the continuous decrease of reservoir water area and the expansion of construction land; 2) the dominant regions of construction land were mainly distributed in the central plains, while the dominant regions of ecological land were mainly distributed in the mountainous regions and the basin regions in the middle part. The distribution exhibited a significant topographic gradient feature; 3) the acreage of the regional comprehensive ecological security pattern in Huailai County was 1470.59 km2, accounting for 82.51% of the total area. The acreage of basic ecological security pattern was 521.33 km2, accounting for 29.25% of the total area, while the acreage of satisfactory ecological security pattern and ideal ecological security pattern was 206.93 km2 (11.61%) and 742.34 km2 (41.65%) respectively. The basic ecological security pattern was mainly distributed in the periphery of critical line and endured relatively low pressure from construction land expansion. The satisfactory ecological security pattern was mainly located in the ecological dominant area and partly limited the construction land expansion, serving as a critical ecological buffer zone of Huailai County. The ideal ecological security pattern was mainly in the interior of critical line and receives more pressure from construction land expansion. Then the government should emphasize the construction of ecological corridor network, which guides the disperse integration of nature patch into construction land in the form of corridor and small plaque. The research methods and results can provide valuable information for regional ecological planning and land use structure optimization.