环渤海海平面上升与三角洲湿地保护

环渤海地区三角洲是我国滨海重要的湿地发育区,在淤泥质滩地型湿地上发育着众多的动、植物群落,成为若干珍稀水禽的栖息地。从地面垂直形变与潮位资料等分析,黄河三角洲和辽河三角洲的地面下降速率为3～4mm/a和3.5～4.5mm/a,而相对海平面上升速率为45～5.5mm/a和5～6mm/a,预计至2050年总体的相对海平面上升量可达40～55cm。海平面上升对三角洲湿地的影响首先是直接淹没大片农田、油井和市区,其次是加剧海岸线的侵蚀与后退,还有风暴潮与洪涝灾害的加剧。针对三角洲湿地生态系统所面临的生态风险与人为活动干扰,有必要采取更加科学合理的保护与开发模式。本文介绍了生境更新与湿地调整的管理策略,以及淤长型滨海湿地的滚动开发模式。交替采用“渐进”与“跃进”的滚动开发,可保持湿地总量的动态平衡,有利于三角洲的可持续发展。

SEA LEVEL RISING AROUND BOHAI SEA AND DELTAIC WETLANDS PROTECTION

Sea level rise in the study area refers to the regional relative sea level rise. It takes place due to relative sea level rise result from the action of local natural factors such as land subsidence due to tectonic subsiding, sediment compaction, and the action of anthropologic factors such as withdrawal of underground water, oil and gas as well as narrowing river channels by dikes in deltaic area against the background of the global sea level rise caused by global warming. Research in the Liaohe and Yellow river deltas indicates that evolution of wetland have been experiencing the serious impacts of the human actions including booming exploitation of wetland against the background of the accelerated regional relative sea level rise. ;Deltaic wetlands around Bohai Sea are important littoral wetlands in China,where a large number of animal and plant communities have developed on the silty muddy flat, including some mostly endangered waterbirds. Analyzed from the data on vertical land deformation and tide level, the subsiding rate of the Yellow river delta and Liaohe river delta has been estimated between 3～4 mm/a and 3.5～4.5mm/a, and the rising rate of sea level were identified between 4.5～5.5 mm/a and 5～6mm/a, respectively. According to the prediction from the research the sea level will increase 40～55cm by year 2050. The effects of sea level rising on the deltaic wetlands include: 1) submergence of a large area of farmland,oil field and urban region; 2) acceleration of coastline erosion; and 3) aggravation of storm surge and flooding hazards. In view of the ecological risk and human disturbance that the deltaic wetland ecosystems will face, more protection measures and development models should be applied. This paper introduced the management strategies of habitat renewal and wetland mitigation, as well as the continual accumulative development model for the littoral wetlands of accretion type. With application of two models of "gradual development" and "jumping development" alternatively, we can maintain the dynamic equilibrium of the area of natural wetlands. Such strategies will be helpful in the sustainable development of deltaic wetlands.