生态保护区外斑块对景观连接度的影响评价

快速的城市化过程带来的生境斑块破碎化及损失会影响物种迁移、捕食等生态活动，对生物多样性构成威胁。然而，现有生态保护区可能无法覆盖其内生物的必要活动范围。生态保护区外的生境斑块对于维持生态过程也具有重要作用，因此识别生态保护区外的关键斑块并加以保护非常重要。以北京市延庆区为研究区，划分两种生境斑块，即核心生境斑块和潜在生境斑块，并基于图论构建生境网络。考虑地表覆盖类型、坡度、人类活动等因素构建生境阻力面。结合未来土地利用类型变化的模拟，研究城市化过程对区域生境网络和景观连接度的影响，选用CLUE-S模型模拟土地利用类型变化的格局。结合生境斑块特征和未来城市土地利用变化情况设计了3种未来生境变化情景。利用连接概率指数(PC)和网络连接度变化率(dI)评价不同生境变化情景下生态保护区外潜在生境斑块的景观连接度重要性，判断保护优先顺序，并分析景观格局变化对不同迁移能力物种的影响。结果表明：生态保护区外的全部潜在生境斑块对维持生境整体景观连接度有最大2.15%的影响，单个潜在生境斑块对维持景观连接度有最大0.28%的影响。此外，景观格局及其变化对不同迁移能力物种的影响差异显著，因此需针对保护物种和城市生境特征设计保护方案，研究区需要优先保护大中型斑块和位于关键位置的小型斑块。为了满足对生物多样性保护的需求，建议在区分生境斑块保护优先顺序时考虑生境斑块对景观连接度的贡献和城市化扩展过程的压力。研究为城市生物多样性保护和生境管理提供了方法参考。

Evaluation of the importance of patches outside protected areas to landscape connectivity

The fragmentation and loss of habitat patches due to the rapid urbanization can affect ecological activities such as species migration and predation which posed a threat to biodiversity. However, the ecological reserves may not be able to cover the necessary activities of the organisms in them. Habitat patches outside of ecological reserves may also play a critical role in maintaining ecological processes. Therefore, it is vitally important to identify key patches outside the ecological reserves and protect them. In this study, we firstly identified two types of habitat patches, core habitat patches and potential habitat patches, and built a habitat network based on graph theory in Yanqing District of Beijing, China. Then we established the habit resistance surface by considering factors such as land cover type, slope, and human activities. The impact of urbanization processes on regional habitat network and landscape connectivity is studied in conjunction with simulations of future land use type changes. The CLUE-S model was selected to simulate the pattern of land use type changes. Finally, we designed three habitat change scenarios based on the characteristics of habitat patches and future urban land use type changes. The connection probability index (PC) and change rate of network connectivity (dI) were used to evaluate the importance of the landscape connection degree of the potential habitat patches outside the ecological reserves under different habitat change scenarios. Based on the results, we judged the priority order of patch protection, and analyzed the impact of landscape pattern changes on species with different migration capabilities. The results showed that the whole potential habitat patches outside the ecological reserves had the greatest impact on the overall landscape connectivity of the habitat by 2.15% and a single potential habitat patch had a maximum effect of 0.28% on maintaining the landscape connectivity. In addition, the impact of landscape pattern and its changes on species with different migratory abilities varied significantly, so it is necessary to design protection plans for species and habitat characteristics. We advise to prioritize the protection of large and medium-sized habitat patches and small habitat patches at key locations. In order to meet the demand for biodiversity conservation, it is recommended that both the contribution of habitat patches to landscape connectivity and the pressure of urbanization expansion process be considered while distinguishing the conservation priorities of habitat patches. The study provides methodological references for urban biodiversity conservation and habitat management.