江苏省自然遗产地生态网络的构建与优化

Abstract

自然遗产地是生物的重要栖息场所,而生态网络是连接自然遗产地的有效途径,如何有效和合理地构建自然遗产地之间的生态廊道,连接破碎生境,对保护自然遗产地生物多样性和区域生态安全具有重要意义.在ArcGIS 9.3的技术支持下,通过合理估算阻力阈值,采用最小耗费距离模型分析方法,构建江苏省省域范围内的自然遗产地生态网络保护体系,并在网络连通性指数分析方法的基础上对生态网络的连通性和有效性进行评价,针对性地提出自然遗产地生态网络的优化措施.研究结果表明:78.28%的林地、88.70%的滩涂滩地、94.37%的草地是自然遗产地生态网络的主要景观组成结构;自然遗产斑块本身对生态网络的构建有较大影响,其中面积较大、长条型的斑块对维持景观连通性的重要性程度贡献较大;研究区现状整体生态连通性指数仅0.001-0.003,连通性水平较差,通过构建生态网络,整体连通性水平可提高到0.044-0.046,可能连通性水平可达到0.074,表明自然遗产廊道的构建可提高景观的连通性水平;在现有生态网络结构的基础上,增加破碎斑块间的生态连接是优化生态网络体系的可行性策略.;Natural heritage sites are important habitats for fauna and flora, and assist in maintaining ecosystem service functions. Often however, human activities and natural threats have damaged the integrity of such sites, and large habitats have become increasingly fragmented. As a result, regional biodiversity conservation has been seriously threatened. To change this situation, ecological networks are being considered as an effective way to re-connect important natural heritage sites. Within a rational ecological network, the flow of material, energy and information among various areas can be ensured and the quality of natural ecosystems can be improved. The effective setting up of ecological corridors and connecting fragmented habitats are crucial actions in the protection of the biodiversity of natural heritage sites, and in the maintenance of regional ecological security. This is especially true in rapidly urbanizing areas: taking natural heritage sites as the core of an ecological network, constructing these networks and undertaking research on ecological values are particularly important actions in this type of developing area. Jiangsu province is located in the coastal area of eastern China where land resources are limited, and has a high population density and a well-developed economy. Human activities have however disturbed the ecological balance seriously, so there is a need to implement regional ecological networks, to integrate natural heritage resources, and to promote the sustainable development of regional ecosystems. For the present study, natural heritage core-areas were firstly selected based on the theory and principles of Landscape Ecology and Conservation Biology, and the different cost values of different landscape types decided with the help of GIS technology. Second, taking Jiangsu Province as an example allowed quantitative simulation of the establishment of natural heritage sites for potential ecological networks using a minimum cumulative resistance model, and the analysis of network connectivity using an integral index of connectivity and probability of connectivity. Third, the main natural heritage corridors in Jiangsu Province were studied, which allowed the determination of suitable optimization measures on the basis of the current corridors. The results show that, in Jiangsu Province, about 78.28% of the forested area, 88.70% of the beach area, and 94.37% of the grassed area together make up the major part of the natural heritage ecological network. These ecological cores have great influence on the establishment of ecological networks. The study also found that the habitats with larger area and greater length have a higher degree of importance in maintaining landscape connectivity. However, the current integral index of connectivity of the study area ranges between 0.001 and 0.003, which indicates poor connectivity. These values would increase to between 0.044 and 0.046, and the possibility of connectivity could go as high as 0.074, if the construction of the proposed ecological networks were achieved. The increment of these values indicates that the construction of natural heritage ecological corridors improves the level of landscape connectivity significantly. Based on the existing ecological network structure, increasing connections between fragmented ecological sites is thus a feasible strategy to optimize the overall ecological network system. Lastly, suggestions on how to achieve optimization of the ecological network are put forward. Overall, the results in this paper provide an important reference point for the sustainable development of natural heritage and biodiversity protection, and also provide useful information for the implementation of natural heritage protection measures.