张家口市生态完整性评估及其影响因素分析

Assessment of ecological integrity and analysis of its influencing factors in Zhangjiakou City

  • 摘要: 城市化和农业生产等人类干扰造成区域生态系统退化, 然而目前尚缺乏一套基于生态完整性的区域人类综合影响评估方法。本研究以首都水源涵养功能区和生态环境支撑区——张家口市为例, 基于景观条件模型, 采用耕地坡度、草地到最近居民点距离、地表水到最近居民点距离、城区面积、公路等级、铁路等级6种人类干扰指标评估2000年和2022年区域生态完整性, 并结合空间自相关和共性分析等多种定量方法, 分析该地区生态完整性的高低值聚集特征和主要影响因素。结果表明: 2000—2022年, 张家口生态完整性整体呈东部高、中部和西部低的格局, 并且出现东部地区生态完整性进一步改善, 其余地区生态完整性不同程度退化的两极化发展趋势。受生态修复项目影响, 东部高生态完整性地区随林地呈块状分布; 受公路建设影响, 中部、北部和南部地区形成以市区为中心并沿公路向四周辐射的低生态完整性格局; 受农牧业生产影响, 西部地区无明显的生态完整性聚集特征。因此, 今后应根据生态完整性评估结果, 针对性设计不同地区的具体管理措施, 改善区域生态完整性。本研究可为区域生态系统人类综合影响评估提供一套科学方法和技术参考。

     

    Abstract: Anthropogenic disturbances, such as urbanization and agricultural production, significantly contribute to the degradation of regional ecosystems. While the concept of human-integrated impact assessments is widely recognized, regional assessment methods based on ecological integrity are less present in China. This study addresses this gap by examining Zhangjiakou City, a critical area for water source conservation and ecological support for Beijing. We employed a landscape condition model to evaluate six anthropogenic disturbance indicators: slope gradient of cropland, distance from grassland to the nearest settlement, distance from surface water to the nearest settlement, urban area size, road grade, and railway grade. These indicators encompass four domains: agriculture and pastoral production, surface water utilization, urbanization, and transportation infrastructure. To quantify the impact scores and maximum impact radius for each indicator, we used a participatory method. This approach led to the creation of separate data layers, each numerically valued from 0 to 1, for each disturbance indicator. These layers were then synthesized into a continuous ecological integrity index using the product method. We conducted spatial autocorrelation, hotspot, sensitivity, and commonality analyses to explore the spatial distribution, clustering characteristics, and primary influencing factors of ecological integrity in 2000 and 2022. Our findings revealed a distinct spatial distribution pattern in Zhangjiakou City: high ecological integrity was observed in the eastern regions, whereas lower integrity characterized the central and western areas. This pattern was influenced by regional resources, transportation, and development orientation. Between 2000 and 2022, a polarization phenomenon in the human impact on ecological integrity was observed. Specifically, human disturbance decreased in areas with high ecological integrity but increased in areas with lower integrity, indicating diverse levels of anthropogenic influence across different regions. In the eastern part of Zhangjiakou City, the high ecological integrity areas are distributed in blocks along with the forest land due to the implementation of ecological restoration projects. Conversely, road construction has created a low-integrity spatial distribution pattern in the central regions, emanating from urban centers and radiating along major roads. The western region, impacted by agricultural and pastoral activities, did not exhibit clear clustering characteristics of ecological integrity. Our study identified cropland, roads, and grassland as the primary factors influencing the ecological integrity of Zhangjiakou City. To mitigate these impacts, we recommend enhancing forest landscape restoration in the eastern region. For the central region, clear boundaries for highway development should be delineated in accordance with the ecological protection guidelines. Additionally, efforts to convert farmland to grassland in the western region should be intensified to improve water supply and enhance the ecological carrying capacity. These initiatives aim to establish an ecological security barrier in the northwest of Beijing and improve the resilience of the region to anthropogenic pressures. This study provides an effective scientific methodology and a technical reference for human-integrated impact assessments of regional ecosystems. This underscores the importance of tailored management interventions based on the spatial aggregation of ecological integrity to address specific challenges posed by anthropogenic disturbances. Such targeted interventions are crucial for promoting sustainable development and enhancing ecological resilience in regions under significant human pressure.

     

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