京津冀城市群扩张模式对区域生态安全的影响预测

当前,城市群是推动我国区域发展的增长极,但其快速的扩张模式对区域生态系统安全的胁迫影响越来越大,已经成为制约城市可持续发展的重要问题,科学地预测城市群未来扩张对区域生态安全格局的影响对区域协同发展的战略实施具有指导意义。以我国最具影响力的京津冀城市群为例,结合空间模型模拟方法及生态系统服务功能评估方法,预测了基于当前京津冀城市群的扩张模式对区域生物多样性保护、防风固沙功能、土壤保持功能与水源涵养等重要生态服务功能的胁迫影响。结果表明:(1)京津冀城市群发展速度较快,但存在区域发展不均衡,呈两极化的发展特征;(2)京津冀城市群具有重要级以上的生态服务功能占区域总面积的三分之一,其中同时包含两种及以上服务功能的地区将近一半,且其空间分布也很不均衡;(3)应用CLUE-S模型可以较好地模拟京津冀城市群未来的扩张格局,模型的Kappa指数为0.84。至2020年,预测京津冀城市群将增加3630.24km~2建设用地面积,而其中约六分之一的新增人工表面侵占具有重要及以上生态服务功能的区域,防风固沙和水源涵养为主要被侵占功能,这些区域集中分布在北京、天津与唐山等核心发展城市;(4)京津冀城市群不均衡的区域扩展模式不仅会进一步加剧不同地区间城市化水平的差距,对区域重要生态系统服务功能的潜在胁迫影响也将会增加。本研究结果可为京津冀城市群协同发展规划与区域生态安全格局保障方案的制定提供科学支撑。

Prediction of expansion pattern and impact on regional ecological security of Beijing-Tianjin-Hebei Metropolitan Region

Rapid urbanization is a growing threat to the eco-environment, and it has seriously restricted the regional social and economic development. Moreover, it has negative effects on the Regional Pattern for Ecological Security (RPES). We studied the Beijing-Tianjin-Hebei Metropolitan Region (BTH), which is one of the most typical agglomerations in China, as a case example to determine the influence of the increasingly changing regional landscape pattern on the future of the RPES. Therefore, we used land-use change to represent the urbanization process, and the distribution of ecosystem services to represent the RPES. It is our hope that this study would provide scientific evidence to support optimizing future regional planning and management. The results were as follows. (1) There was a marked change in the landscape patterns in the BTH, which was faced with the problem of imbalanced development. (2) The area of high and very high ecosystem services accounted for one-third of the total area of the BTH, including nearly half that contained more than two services. (3) The CLUE-S model was robust in its applicability for simulating the land-use dynamic changes of the BTH, and the kappa index was 0.84. The ecosystem services occupied by the artificial surface accounted for one-sixth of the new increased artificial surface, and the main occupied services were sandstorm prevention and water retention. Furthermore, the occupation mainly occurred in growing cities such as Beijing, Tianjin, and Tangshan. (4) The imbalanced development of the BTH would not only enhance the gap between different cities but would also increase the potential threats to the pattern of regional ecological security. Therefore, the ecosystem services that would restrict the urban expansion should be considered, and this would facilitate the protective strategies for the RPES and future coordinated development of the BTH.