时空动态视角下快速城市化地区景观生态风险评价与分区

    Assessing landscape ecological risk in rapidly urbanized areas from the perspective of spatiotemporal dynamics

    • 摘要: 景观生态风险是区域景观受多种风险源长期干扰的累积结果。立足风险发生的“历史-现期-未来”动态视角探讨景观生态风险分区管控策略可为优化区域生态风险管理提供思路借鉴。为科学认知景观生态风险的空间分异格局,继而制定空间分区管控策略,研究基于快速城市化地区的风险动态管控需求,构建了“历史-现期-未来”时空动态视角下的景观生态风险评价与管控分区框架,并以江阴市为例,探讨其风险变化的时空过程、演变特征、未来趋势及差异化管控策略。结果表明:1)2005—2020年,伴随城市化演进,江阴市耕地减少12.76%,建设用地增加13.53%,景观类型转化剧烈、景观破碎度持续增加。其中,耕地和生态用地转化为建设用地的程度较严重,而建设用地集聚分布态势显著。2)江阴市生态风险呈现“北低南高”的空间分布格局。低风险区集中分布在北部水域及乡镇建设用地核心区,高风险区分布在南部水域、沿江地带及乡镇建设用地扩张边缘区。3)基于风险的动态变化过程,江阴市景观生态风险演变类型可划分为维持型、升级型、缓和型和波动型。继而,依据风险现状和未来趋势进一步分析不同区域的风险控制需求与风险走向,细化具体的防范区,不同区域在风险防范紧迫性、管控重点等方面存在显著差异。总体上,集成景观变化“历史-现期-未来”视角的风险评价和管控框架有益于从时空动态全过程理解城市化地区景观与外界干扰之间的复杂相互作用,研究结果可为城市生态风险管理及促进区域国土空间布局优化提供决策支持。

       

      Abstract: Landscape ecological risk can be attributed to the cumulative effect of long-term disturbance in the regional landscapes by various risk sources. Fortunately, zoning control strategy can be expected to optimize the regional ecological risk using the dynamic perspective of the "history-present-tuture" of risk occurrence. This study aims to scientifically understand the spatial differentiation pattern of landscape ecological risks, and then formulate spatial zoning management and control strategies. A systematic investigation was also made on the dynamic risk management and control needs of rapidly urbanized areas. The new framework was established for the landscape ecological risk assessment and management zoning from the spatiotemporal dynamic perspective of "history-present-tuture". Taking the Jiangyin City of Jiangsu Province as the research area, the differentiated management and control strategy of risks was proposed to explore the spatiotemporal process, evolution characteristics, and future trends of landscape ecological risk. The combination characteristics of landscape risk levels were obtained from the coupling perspective of "history-present-tuture". The results showed that: 1) The cultivated land decreased by 12.76% from 2005 to 2020, whereas the construction land increased by 13.53% with the evolution of urbanization. There was a drastic transformation of landscape types, where the landscape fragmentation continued to increase. Among them, there was the more serious conversion of cultivated and ecological land into construction land. The fragmentation and uneven distribution were found in the landscape of cultivated and ecological land, with a significant trend in the agglomeration distribution of construction land. 2) The ecological risk presented a spatial distribution pattern of "low in the north and high in the south". The low-risk areas were distributed in the northern waters and the core area of township construction land, whereas, the high-risk areas were distributed in the southern waters, along the river, and the marginal area of township construction land expansion. Therefore, Jiangyin City was focused mainly on the expansion of construction land in the process of rapid urbanization. The high intensity and scattered construction caused the fragmentation landscape of cultivated and forest land, indicating the high risk. 3) The landscape ecological risks were categorized as the maintenance, upgrading, mitigation, and fluctuation types, according to the dynamic process of risks. The proportion of risk maintenance type was the highest, followed by upgrading and easing types, while the fluctuation type shared the lowest proportion. Furthermore, the control needs and trends of risks were further analyzed in the different regions to determine the specific prevention areas, according to the current situation and future trends of risks. There were also significant variations in the urgency of risk prevention for the management and control in different regions. Among them, much attention should be paid to the high-risk areas with serious out-of-control or a basic level of control. In summary, the risk assessment and management framework with the perspective of a "history-present-tuture" landscape is beneficial to understanding the complex interaction between landscape and external disturbances in the urbanized areas from the dynamic process of time and space. The findings can also provide the decision support for the urban ecological risk management for the optimization of regional territorial spatial layout.

       

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