中国沿海陆地自然保护区景观连接度评价

人类社会发展进入人新世时期,以人类活动为主导的高频率干扰和自然资源的高强度开发对生态环境造成严重威胁,提升自然保护区的景观连接度是缓解和应对外界干扰的关键手段之一。传统意义上景观连接度研究侧重于景观基质对物种迁徙的累积负向阻碍作用,评价体系中忽略了生物多样性对物种迁徙的正向支持作用。本文以中国沿海省份作为研究区域,将生物多样性空间分布作为生态系统关键功能的表征,并将其纳入景观连接度评价体系,构建了生态廊道的连通适宜性及生态支持力二维评价新方法,进一步分析人类活动干扰和物种空间分布对自然保护区景观连接度的影响。研究结果表明沿海地区人类活动对景观连接度的影响存在明显的边缘效应,即自然保护区边缘地带的人类干扰范围（46.46%）明显高于其内部区域,人类活动干扰使保护区面积减少约720.25 km²,且造成廊道起点和终点位置的改变。自然保护区边缘地带人类干扰导致了研究区域内95条廊道的连通适宜性下降;78条廊道的生态支持力有明显提升,“一降一升”的评价结果能有效地衡量景观基质对物种迁移的支持能力变化。基于景观基质阻碍和促进作用的二维评价可为中国未来自然保护区连通性和生物多样性保护提供更为全面的时空格局动态变化模拟,为优化自然保护区空间布局提供更为完善的景观连接度评估新方法。

Evaluation of landscape connectivity in China's coastal terrestrial nature reserves based on an improved minimum cumulative resistance model

Rapid urbanization in the Anthropocene has altered the interaction between human and natural systems in coastal areas of China. High frequency of disturbances caused by human activities poses great threats to coastal ecosystems, which in turn leads to coastal fragmentation and biodiversity loss. Landscape connectivity in interlinking adjacent national nature reserves is one of the key approaches to eliminate the increasing threats from human disturbances. Traditional simulation of landscape connectivity focuses on the cumulative negative resistance of landscape matrix along species migration, but ignores the positive impacts of ecosystem on migration. In this study, we proposed an innovative evaluation index system to assess landscape connectivity by integrating suitability and ecological capacity based on species distribution in China's coastal areas. We combined the advantage of traditional landscape connectivity model and species distribution to develop a method for integrating both ecological factor and human activity data. We found that human activities in coastal areas resulted in an edge effect on landscape connectivity near the boundary of nature reserves during 1995-2015. Human disturbance caused a loss of 720.25 km² for the nature reserves, while the edge of the nature reserves undertook higher risks from human activities (46.46%). High level of human disturbance altered the starting and terminal locations of corridors while connecting adjacent nature reserves. Our results showed that the connectivity suitability of 95 corridors decreased due to the increase of human disturbance, while the ecological capacity of 78 corridors was significantly improved in terms of biodiversity distribution. This two-dimensional assessment based on the resistance and ecological capacity of landscape matrix can be provided a comprehensive simulation to estimate the dynamics of spatial and temporal patterns in connectivity and biodiversity conservation.