基于图论的景观连接度量化方法应用研究——以福建省闽清县自然森林为例

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 基于图论的景观连接度量化方法应用研究——以福建省闽清县自然森林为例 DOI: 10.5846/stxb201507301599 作者: 作者单位: 复旦大学环境科学与工程系,复旦大学环境科学与工程系 作者简介: 通讯作者: 中图分类号: 基金项目: 国家社科基金重大资助项目（14ZDB140） Evaluation method for landscape connectivity based on graph theory: a case study of natural forests in Minqing County, Fujian Province Author: Affiliation: Department of Environmental Science and Engineering,Fudan University,Department of Environmental Science and Engineering,Fudan University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:气候变化和人类活动导致的自然生境丧失和生境片断化使全球生物多样性面临威胁，而有效缓解这类问题的手段之一是维持自然生境的景观连接度。图论分析法作为景观连接度研究的新途径成为研究领域热点，但仍然存在提高距离阈值取值的科学性、充分解读图论连接度指数等有待探究的问题。以闽清县自然森林为对象使用图论分析方法进行了景观连接度的量化研究，提出并使用了距离阈值综合取值方法，联合使用了多种景观连接度指数。研究结果表明，距离阈值综合取值方法能够提高取值的准确性并具有广泛适用性，二进制连接度指数与概率连接度指数能够从不同角度指示景观结构和斑块重要性格局。研究区域90%以上的景观连接度由主要景观组分维持，数量很少的极高重要值斑块数能够对整体连接度水平产生显著影响。面积越大的斑块重要性指数越高，但是极高重要值斑块的重要性指数并不完全取决于斑块面积，而更多的与斑块位置等因素相关。本研究进一步完善图论分析法在景观连接度研究方面的应用，对生物多样性保护工作具有参考价值。 Abstract:The loss of natural habitat and habitat fragmentation, caused by climate change and human activities is a seriously threat global biodiversity. Maintaining landscape connectivity of natural habitats is one of the most effective methods for alleviating these related problems. Landscape connectivity describes the degree to which the landscape facilitates or impedes ecological flow and movement among habitat patches. By integrating information related to landscape structure and ecological processes, landscape connectivity describes the effects of habitat fragmentation on the organisms living within the landscape. Graph theory provides powerful tools for assessing landscape connectivity, and has become a popular research method in recent years. However, some issues related to the application of graph-based methods still need to be discussed and analyzed, such as choosing a proper threshold distance and gaining an understanding of various connectivity indices. This study used the graph theory method to assess the landscape connectivity of natural forest in Minqing County, Fuzhou City, China. A comprehensive method was utilized to assign a reasonable threshold distance, which consisted of three steps:namely, determining the range of the maximum dispersal distance of a focal species, enumerating a gradient distance value, and an experiment using link thresholding. Six indices were used to assess the landscape connectivity of the study area:number of links (NL), number of components (NC), Harary index (H), area-weighted flux (AWF), integral index of connectivity (ⅡC), and probability of connectivity (PC). We harvested data related to the natural commonweal forests of Mingqing County from the data of 2010 National Forest Resource Inventory using ArcGIS 10.2 to define habitat patches in the study area. The six landscape connectivity indices were calculated using Conefor Sensinode 2.6 software. Using the comprehensive method, 1 km was found to be the optimal threshold distance that best presented the structure of the landscape. A medium-level structure, consisting of 56 components was detected using the NL and NC indices. Based on the binary (H, ⅡC) and probability (AWF, PC) indices, the level of landscape connectivity of the natural forests in Minqing is comparatively low. The patch importance indices (dIs) aided in identifying the most important patches that could potentially affect the overall level of connectivity. We determinded that the main component provided 90% of the connecting functions in maintaining the landscape connectivity; however, losing a single critical patch could significantly reduce overall connectivity. The results indicated that this new method involving evaluation of the threshold distance could help researchers determine more accurate distance values for landscape connectivity, and therefore, this method would be applicable for both scientific research and planning. In addition, binary and probability indices could be used together to reveal landscape structure and the spatial patterns of patch importance. In our analysis, we found that the values of dI are generally proportional to the area of patches; however, patch area is not the dominate element that determines the dI values of the most critical patches. Other patch features, such as patch position, may have greater influence on the dI values for the extremely important patches. This may be caused by a commonly used but inaccurate method of evaluating patch attributes. This topic required further investigation and improvement in future studies. In conclusion, this study will help promote the application of graph theory in research studies related to landscape connectivity, and can provide guidance for land managers tasked with conserving biodiversity. 参考文献 相似文献 引证文献