自然保护区及周边的景观格局变化与驱动力分析———以贵州省兴义坡岗自然保护区为例. (Chinese)

Habitat loss in a nature reserve with its surrounding areas will result in isolating of habitat patches, degrading of ecological function, and intensifying of landscape fragmentation in the reserve. Past studies of habitat loss paid more attention to those within the boundary of the reserves of interests, whereas less concern was given to their surrounding areas. It also must be recognized that our knowledge of pivotal habitat patches and corridors in a nature reserve was far from applicability. In this study, the Xingyi Pogang Nature Reserve, Guizhou, China with supposed gradient buffer in the surrounding were selected as our research target for habitat loss research. It investigated the spatiotemporal changes and gradient effects of the landscape pattern from 1990 to 2015 in the Reserve by moving window analysis based on long-term land use data. By graph theory methods, it also identified the pivotal habitat patches and connecting corridors and their changes, which mattered a great to the functional connectivity of the overall habitat circumstances. Findings are as follows: (1 ) During the 25 years, cultivated land areas of the Pogang Reserve and surrounding areas had decreased; the artificial surface areas had increased, and the forest areas described a trend of first decreasing and then increasing, and a final decreasing. With the extension from the hedged Reserve to its surrounding, the dominant position of forest areas in landscape pattern had gradually decreased. (2 ) The intensity of the landscape pattern changes in the surrounding areas of the Reserve was greater than those within the boundary of the Reserve. The value of the Largest Patch Index ( LPI ) was smaller than those in the Reserve, mostly clustering in the gradient buffer zone of 5 — 10 km beyond the boundary of the Reserve. Under the influence of urbanization expansion and traffic development, the level of landscape fragmentation was intensified in the northwest area of the study area. There was a gradient effect in the changes of landscape pattern in the surrounding areas of the Reserve. With the extension of the gradient buffer around the Reserve, the proportion of artificial surface areas increased gradually; The Shannon Diversity Index ( SIMI) was significantly positively correlated with the extension of gradient buffer zone. ( 3) Combined with scenario analysis of migration distances of species, the areas which had the functional connectivity index in significant decreasing were identified ; the pivotal connecting corridors for bridging of species and landscape networks were identified. (4) Agricultural activities and urbanization were the main driving factors for the changes of landscape pattern in the study area. The research results provide support for the identification of the key areas with obvious landscape changes and habitat connectivity of the Xingyi Pogang Nature Reserve as well as surrounding areas, and provide scientific reference for ecosystem protection and landscape pattern optimization. [ABSTRACT FROM AUTHOR]

自然保护区及周边区域生境丧失会造成保护区生境斑块隔离、生态功能削弱、景观破碎化加剧。以往多 数研究主要集中在保护区边界范围以内，对保护区周边区域关注不够，对重要生境斑块和廊道识别的研究不足。 本研究基于长时间尺度土地利用数据，以贵州兴义坡岗自然保护区及周边区域构建的梯度缓冲区为研究对象，利 用基于移动窗口的景观格局指数和基于图论的景观功能连接度方法，分析了区域1990 - 2015 年景观格局的时空 变化特征和梯度效应。结果表明：（１）25 年间，坡岗保护区及周边区域耕地面积减少，人工表面面积增加，林地面 积出现先减少、后增加、再减少的趋势。研究范围从自然保护区向其周边区域过渡过程中，林地在景观中面积占比 的主导地位逐渐降低。（２）保护区周边区域景观格局变化强度大于保护区边界内，最大斑块指数相比保护区内下 降，且主要集中在保护区周边５～１０ｋｍ范围。研究区西北方向受城镇化扩张和交通发展影响，景观破碎化程度加 剧。保护区周边景观格局变化存在梯度效应，随保护区周边梯度缓冲区外延，人工表面面积占比逐渐增加，香农多 样性指数随梯度缓冲区的外延呈极显著正相关。（３）结合物种迁移距离情景分析，揭示了功能连接度指数下降明 显的区域，识别了对物种及景观网络连接具有重要作用的廊道。（４）农业类活动、城镇化及城市开发建设是研究区 景观格局变化的主要驱动因素。研究结果对坡岗自然保护区及周边景观格局变化规律和生境连接关键区域的识 别提供支撑，为生态系统整体性保护及格局优化提供了科学参考和依据。 [ABSTRACT FROM AUTHOR]

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