基于指标体系法的渤海湾生境状况评价

Habitat Assessment of Bohai Bay Based on Indicator System Method

生境状况评价是科学客观认知海湾环境及其栖息生物状态并揭示时空演变趋势的评估方法。建立以压力源为驱动的核心指标体系,通过中尺度区域的指标状况空间量化和长时间序列趋势比对,给出评估区域(渤海湾)的指标临界值并建立定量评价模式,判断渤海湾生境状况的时空特征与演变趋势。结果显示,渤海湾水质状况为一般,趋势为向好变化,且参评因子的变化均为向好趋势;沉积物生态风险指标为优秀状况,向好趋势,2011-2017年重金属潜在生态风险危害指数(RI)和潜在生态风险系数(E_(r)^(i))趋势均表现为明显降低;浮游植物、底栖生物的物种多样性指数均为一般状况,从变化趋势来看,浮游植物为向差趋势,底栖生物为向好趋势;近年来鸟类数量和种类增长的指标评价为良好状况,向好趋势;渤海渔业资源持续恶化,指标状况为较差;潮间带湿地退化率超过60%,栖息地退化严重,状况为恶劣;自然岸线急剧减少且破碎化严重,岸线利用呈持续高强度,指标状况为一般,变差趋势。研究表明,指标评估结果客观反映了渤海湾的生境压力来源和长期性问题,相较于环境治理,生态系统保护与恢复需要持续关注。

Habitat assessment of Bohai Bay is a good way to understand the status,scientifically and objectively,of the gulf environment,and to reveal spatio-temporal trends and biodiversity of the bay.In this study,we established a quantitative habitat evaluation system for Bohai Bay and assessed the spatiotemporal characteristics and trends of environmental conditions.The indicator system for habitat evaluation of Bohai Bay was constructed based on the rules of source driven environmental pressure and indicators were selected from aspects of environmental quality,biodiver-sity and habitat conditions.Critical values of the indicators were quantified spatially at the meso-scale(region)and temporarily as long-term trends.We aimed to provide scientific evidence for the effective preservation and comprehensive environmental management of Bohai Bay.The water quali-ty of Bohai Bay was generally fair,but trending upward with all evaluation indicators improving.The ecological risk index of sediment was excellent and trending upward.The potential ecological risk factor(E_(r)^(i))and risk hazard index(RI)of heavy metals presented a clearly declining trend from 2011 to 2017.The species diversity of phytoplankton and benthos were generally fair,and phyto-plankton diversity trended downward,while benthos diversity trended upward.The number and species richness of birds increased in recent years,but the fishery resources of Bohai Sea continued to deteriorate and the status and trend of each fish indicator were poor.The degradation extent of intertidal wetlands exceeded 60%,habitat degradation was serious,and the status of each indicator was poor.The natural coastline was sharply reduced and seriously fragmented,and coastline devel-opment intensified continuously,with an indicator status of fair.The evaluation results objectively reflect sources of habitat pressure and identify long-term problems in Bohai Bay.Clearly,protection and restoration of this large ecosystem is an arduous,long-term effort and will require perseverance.