围填海对海洋水动力与生态环境的影响

Impact of land reclamation on marine hydrodynamic and ecological environment

近10年来,中国海岸带围填海活动呈现出规模大、速度快的发展态势。围填海能带来显著的经济效益,但对海洋环境与生态的负面影响也不可忽视。针对围填海对海洋环境和生态的影响及作用机制,分别从水动力和生态系统两个方面进行了概述。围填海改变了海洋的自然几何属性(原始岸线、地形地貌、海湾面积),引起水动力环境的变化(潮汐系统和海湾水交换能力),进而影响了海湾的环境容量;围填海破坏了生物栖息地、导致生物多样性的丧失,影响到生态系统结构与功能的稳定性;水动力与生物多样性的变化可显著影响到生物地球化学过程,加速富营养化进程,恶化水质,增加生态灾害风险。目前,围填海后的生态修复策略主要有增加生物量、建设自然保护区、退陆还海3种方式;而生态补偿策略则多基于"生态系统服务功能与生境面积的大小为线性关系",通过对其经济价值的量化后进行生态补偿与实施相关政策。国际上,生态系统服务功能的量化参数逐步纳入实际管理,并在线性关系研究的基础上,逐步纳入一些非线性的理念,使生态补偿机制更为合理化;而我国对于围填海生态效应的定量化研究及科学理论在管理政策中的实际应用仍亟待提高。整体而言,全面、准确地评估围填海对海洋环境与生态的影响离不开自然科学与社会科学的交叉与融合。

Over the last decade,land reclamation with a large scale and fast speed has developed along the Chinese coastline.Land reclamations can earn profits for local economy but also produce significantly negative influences on marine ecosystems.We summarized the impact and mechanism of land reclamation on the marine environment and ecosystem in terms of hydrodynamics,biodiversity,and biogeochemical process.By means of changing its natural geometry（shoreline,geomorphology,and water area）,land reclamation impacts ocean hydrodynamic environment（tidal regime and capacity of water exchange）and weakened the environmental capacity of bays.Large scale land reclamation can damage coastal habitat,significantly reduce the biodiversity,and threaten ecosystem structure and function.Meanwhile,the changed hydrodynamics and reduced biodiversity can influence the process of biogeochemical cycle,which will accelerate eutrophication and increase the risk of ecological disaster.The ecological remediation is very critical for reducing the negative impact from land reclamation.Three ecological methods are suggested to do remediation after land reclamation,which include increasing the biomass,establishing natural reserve,and returning the land back to sea.Based on the linear relationship between the ecosystem services and the ecological habitat area,the strategy and policy of ecological compensation are applied for quantifying its economic value.Internationally,based on the above linear relationship,quantitative parameters of ecosystem service and functioning have gradually applied into environmental management.With some nonlinear theories developed,the method of ecological compensation has been more and more reasonable.In China,the quantitative research on the environmental and ecological effect of land reclamation and the practical application of scientific theory in management are still need improved.According to current research status and trend,the cross and integration of natural science and social science may be the most sensible and best way to the synthetically and accurately evaluate the impact of land reclamation on marine environment and ecosystem.