中国科学院海洋研究所机构知识库

海岛是四面环海并在高潮时高于水面的自然形成的陆地区域。海岛位置的特殊性，决定了其特殊的地理环境。相对于陆地而言，海岛上的植被、土壤、气候等自然因素都有一定的差别。海岛的社会经济条件与陆地差异较大，海岛上人们的生活方式、劳动工具等，都会直接影响海岛的生态系统。近些年来，海岛旅游业的兴起、海洋资源的开发等，使得海岛的开发强度加大，海岛生态系统也遭到了威胁，越来越多的学者开始关注海岛生态系统的保护。

海岛生态脆弱性指的是海岛生态系统受外部干扰后引起的不利影响的敏感度和不适度。建立完善的海岛生态系统评估体系，并且将该评估体系进行试点评估，对于高强度开发海岛的生态系统保护有重要意义。我国对于海岛的生态脆弱性的研究起步较晚，有关海岛生态脆弱性的研究尚未建立针对于高强度开发型海岛的专用评估理论和方法。本文通过评估海岛的暴露度、敏感度和适应力三个方面，构建了高强度开发海岛的生态脆弱性评估指标体系。以我国山东省烟台市的南长山岛和北长山岛及其周边海域为本研究的研究区，通过实地调研、野外调查、资料收集等有关工作，在研究区运用构建的评估指标体系对南、北长山岛及其周边海域的生态脆弱性进行了评估。通过贝叶斯网络分析模型对生态脆弱性评估结果和影响长岛生态脆弱性的各个指标进行条件概率分析，从概率的角度分析了评估体系中各个指标对岛陆生态脆弱性的影响程度。结合熵差法，提取了对生态脆弱性影响程度最大的关键指标。最后，结合关键指标和影响程度，以空间可视化的形式对生态脆弱性可优化地区进行展示。基于长岛生态脆弱性研究结果，本研究提出了既能保护长岛重点生态功能区，又能够兼顾长岛的经济社会发展需求的生态管控建议。本文的研究结果有：

（1）通过评估海岛的暴露度、敏感度和适应力，结合高强度开发海岛的特征，选择了自然因素指标和人文因素指标。通过查阅文献、实地调研和结合前人的研究，构建了包含23 个评估指标的高强度开发海岛的生态脆弱性评估体系。

（2）运用构建的评估指标体系，对山东省烟台市长岛地区进行试点评估。根据南、北长山岛生态脆弱性评估结果，长岛地区生态脆弱性程度低，表现为不脆弱、临界脆弱或轻度脆弱。其中，海域地区无脆弱区，附近海域均为不脆弱区（1219 公顷）和临界脆弱区（2528 公顷）。岛陆地区含不脆弱区（412 公顷）、临界脆弱区（1445 公顷）和轻度脆弱区（368 公顷）。其中，北长山岛的中西部、南长山岛的东南部部分地区受到的外界干扰等较多，加之自身的属性易受外部影响发生改变，使这些地区的生态脆弱性相对较高，生态系统表现为轻度脆弱。岛陆部分的沿海地带多处于不脆弱或临界状况。这些地区虽然受到外界的干扰大，但由于其自身属性导致这些地区极不易受外界影响而发生改变，所以生态系统脆弱性低，生态系统表现为不脆弱或轻度脆弱。北长山岛和南长山岛相较，北长山岛生态脆弱区占北长山岛总面积的29.97%，南长山岛生态脆弱区占南长山岛总面积的8.79%，北长山岛的生态脆弱性高于南长山岛，北长山岛生态状况更容易受到外部影响而发生改变。

（3）运用贝叶斯网络分析模型，获得了评估结果与评估指标两两结合同时发生的条件概率。利用熵差法，计算得到NPP、陡坡占比、地下水、土壤和岛陆开发的熵差分别为0.21、0.55、1.05、1.13 和1.42，NPP 和陡坡占比两个指标的熵差最小且均小于1，说明NPP 与陡坡占比与生态脆弱性关联度最高。

（4）选择NPP 和陡坡占比作为影响生态脆弱性评估的关键指标，根据关键指标的状态子集，结合生态脆弱性评估结果，选择出了可以降低地区生态脆弱性的一级优化区（可以优化为不脆弱的地区）和二级优化区（可以优化为临界脆弱的地区）。南北长山岛生态脆弱性一级优化区域非常少，仅有4 公顷。其中，北长山岛有3 公顷的分布，南长山岛有1 公顷的分布。二级可优化区域的面积共有184 公顷，且二级可优化区域多分布于北长山岛。北长山岛共有二级可优化区126公顷，而南长山岛共有二级可优化区58 公顷。这些地区应该作为生态保护的重点区域。建议地方政府加强对这些地区的生态保护，限制开发，保障经济社会与生态环境的和谐发展。

The island is an independent region, and its special location determines the special geographical environment. Compared with the land, the natural factors such as vegetation, soil, and climate are different. The social and economic conditions of the islands are more different from those of the land. The way of life and work of the people living on the island directly affect the ecosystem of the islands. With the rise of island tourism and the development of marine resources, the intensity of island development has increased in recent years, and then the island's ecosystem has been threatened. It is urgent to assess the vulnerability of the island's ecosystem. At the same time, many scholars have begun to pay attention to the protection of islands. More and more people pay attention to the special ecological significance of islands. Establishing a valuable island ecosystem assessment framework and conducting pilot assessment of the assessment framework is essential for island ecosystem vulnerability assessment. At present, our country is still at the stage of investigation on islands. The research on islands started late and the number was small.

At present, there is no systematic theory and method for island ecological vulnerability assessment, and the evaluation is mostly qualitative analysis on macro level. In this paper, through the selection of exposure-sensitivity-adaptation model, referred to as ESA model, the index system is selected under this model to construct an index system for assessing the ecological vulnerability of highly developed islands. South Changshan Island and North Changshan Island in Shandong Province and their surrounding sea areas are the research areas, which have the typical characteristics of high-intensity island development. Through field investigation, field investigation, data collection and other related work, a pilot evaluation was carried out in this area using the index system to explore the rationality of the evaluation results. This paper also uses Bayesian network analysis model to carry out conditional probability analysis of each index affecting the ecological vulnerability of islands, and evaluates the impact degree of each index on the ecological vulnerability from the perspective of probability. The driving force of each index to ecological vulnerability was evaluated by the method of entropy difference. Finally, through the analysis of driving forces, the spatial expression of ecological vulnerability can be optimized. The results of this study are as follows:

(1) By evaluating the exposures, sensitivities and adaptabilities of the islands, and combining with the characteristics of high-intensity developed islands, natural and human factors indicators were selected. Based on literature review, field investigation and previous studies, a assessment system for the ecological vulnerability of high intensity developed islands with 23 assessment indicators was constructed.

(2) The pilot evaluation of Changdao island in Yantai City of Shandong Province is carried out by using the established assessment system. According to the results of ecological vulnerability assessment of Changshan Island, the ecological vulnerability of Changshan Island is low, which shows that there are not vulnerable, critical vulnerable and slightly vulnerable areas. Among them, there are no vulnerable areas in the sea area, and the adjacent sea areas are all non-vulnerable areas (1219 hectares) and critical vulnerable areas (2528 hectares). The island land area includes non-vulnerable area (412 hectares), critical vulnerable area (1445 hectares) and mild vulnerable area (368 hectares). Among them, the central and western part of North Changshan Island and the southeastern part of South Changshan Island are subject to more external interference, and their own attributes are vulnerable to external influences, which makes the ecological vulnerability of these areas relatively high, and the ecosystem is slightly fragile. The coastal areas of the island land are mostly in a non-fragile or critical condition. Although these areas are greatly disturbed by the outside world, due to their own attributes, these areas are extremely vulnerable to external influence and change, so the ecosystem vulnerability is low, and the ecosystem is not fragile or slightly fragile. Comparing North Changshan Island with South Changshan Island, the ecological fragile area of North Changshan Island accounts for 29.97% of the total area of North Changshan Island, while the ecological fragile area of South Changshan Island accounts for 8.79% of the total area of South Changshan Island. The ecological fragility of North Changshan Island is higher than that of South Changshan Island, and the ecological condition of North Changshan Island is more vulnerable to external influences and changes.

(3) Using Bayesian network analysis model, the conditional probability of the combination of evaluation results and evaluation indicators is obtained. The entropy difference of NPP, steep slope ratio, groundwater, soil and island land development is 0.21, 0.55, 1.05, 1.13 and 1.42, respectively. The entropy difference of NPP and steep slope ratio is the smallest and is less than 1, which indicates that the correlation between NPP and steep slope ratio and ecological vulnerability is the highest.  

(4) NPP and steep slope ratio are selected as the key indicators affecting ecological vulnerability assessment. According to the state subset of key indicators and combined with the results of ecological vulnerability assessment, the first-level optimization zones (which can be optimized to non-vulnerable areas) and the second-level optimization zones (which can be optimized to critical vulnerable areas) are selected to reduce the ecological vulnerability of the region. There are very few primary optimization areas for ecological vulnerability of Changshan Island, with only 4 hectares. Among them, there are 3 hectares in North Changshan Island and 1 hectare in South Changshan Island. There are 184 hectares in the area of the second-level optimum area, and the second-level optimum area is mostly distributed in North Changshan Island. North Changshan Island has 126 hectares of secondary optimum area, while South Changshan Island has 58 hectares of secondary optimum area. These areas should be the key areas of ecological protection. It is suggested that local governments strengthen the ecological protection of these areas, restrict the development, and guarantee the harmonious development of economy, society and ecological environment.