湖南省城市群生态网络构建与优化

大型生境斑块为区域生物多样性保护提供了重要的空间保障。然而,快速城市化使得大型生境斑块变得日益破碎化、岛屿化,连接性不断下降,且日益受到周边土地利用变化的强烈影响,已严重威胁着区域生物多样性的保护。通过生态廊道建立或修复破碎生境斑块之间的连接,将非常有利于生态网络生态服务功能的有效发挥。基于景观生态学和保护生物学的相关原理,以湖南省城市群为例,在RS和GIS技术的支撑下,采用最小费用路径和情景分析方法,定量模拟了研究区的潜在生态廊道,基于重力模型对重要生态廊道进行了识别与提取,并就消费面模型对潜在生态网络结果产生的影响进行了分析,在此基础上有针对性地提出了生态网络优化的对策。研究结果表明,林地和耕地是组成研究区生态网络的优势景观要素类型;不同生境斑块间的相互作用强度差异显著,总体上西高东低,南高北低;消费面模型能够在较大程度上影响到生态网络的分析结果,因而进行情景分析十分重要和必要。研究结果可为研究区生态网络的构建和优化提供科学依据,同时可为其他城市群区域生态网络的构建提供参考和借鉴。

Developing and optimizing ecological networks in urban agglomeration of Hunan Province, China

On a regional scale, large habitat patches which are important regional sources of biological diversity can provide important functions in habitat protection for biodiversity conservation. However, due to rapid urbanization, large habitat patches have become increasingly fragmented, and are almost like an island surrounded by the built-up area. The connectivity among these habitat patches is gradually waning. Changes in land use around these large patches have very strong impacts and seriously threaten regional biodiversity conservation. Habitat fragmentation would lead to smaller and more isolated animal populations and the isolated populations are more vulnerable to local extinction and inbreeding depression. An Ecological network is a representation of the biotic interaction in an ecosystem while ecological network planning is a method that combines fragmented habitat patches to form landscapes with spatial integrity and habitat networks. This method can help raise the quality of natural ecosystems and protect biodiversity. Thus, the establishment of ecological networks and the restoration of the links between isolated habitat patches would be quite beneficial to ecosystem services. In this paper, based on the theory and principles of Landscape Ecology and Conservation Biology, taking urban agglomeration in Hunan Province as the example, the potential ecological corridors were quantitatively simulated using the Least-Cost Path and Scenario Analysis Methods with the help of Remote Sensing and GIS technology. The strength of the interaction between green patches was then evaluated quantitatively based on the Gravity model. The impacts of the result of potential ecological networks by the cost surface were also analyzed. Finally, suggestions on how to optimize the ecological network were accordingly put forward. This paper tried to answer the following three questions: (1) what are the potential ecological corridors of urban agglomeration in Hunan Provence and how to determine the relative importance of these ecological corridors scientifically? (2) how to optimize the constructed ecological networks for better maintenance of regional biodiversity? (3) to what extent can the cost surface modal influence the result of ecological network analysis? The results showed that: (1) woodlands and farmlands are the superior landscape types in the ecological network of the study area; (2) the reciprocity between different habitat patches is quite varied, and has decreased from west to east and south to north; and (3) cost surface has a strong impact on the results of the potential ecological corridors analysis, so scenario analysis is very important and essential. The results in this article can provide the scientific basis for developing and optimizing ecological networks on a regional scale, and can also provide important references for the construction of ecological networks in other urban agglomeration.