摘要
七里海古泻湖湿地位于天津市宁河县西南部,是全新世以来海退过程在天津平原留下的众多古泻湖湿地之一。分析了七里海古泻湖湿地形成、演变的区域地质背景,指出七里海古泻湖至少经历了3次大规模萎缩,其西南部萎缩较快,东北部萎缩相对较慢。利用历史资料研究了近5000a七里海古泻湖湿地的形成、演变过程,并以1950年航空照片和1976年、1981年、1987年、2000年、2005年的MSS、TM和ETM+影像数据为主要数据源,用遥感和地理信息系统技术研究了近百年七里海古泻湖湿地的环境变化。结果表明,距今5000a,七里海地区为海相沉积环境,海岸线穿越宁河的潘庄镇、大海北、小海北一带;距今3800~3000a,海岸线退至造甲城、七里海镇一带;到清朝乾隆年间,七里海湿地逐渐被分割成前海、后海、曲里海3部分,湖底不断淤积,水面不断萎缩,逐渐演变为湖泊、沼泽湿地;1926~2005年间,七里海湿地大致经历了3个变化阶段:1926~1950年为自然变化阶段,七里海湿地的变化主要受自然因素的影响,该阶段七里海湿地仍由前海、后海、曲里海3部分组成;1951~1981年为改造治理阶段,七里海被潮白河拦腰截断,分为东、西七里海,后海被改造为农田;1982~2005年为围垦和水产养殖阶段,东、西七里海的大面积水域以及湿地周围的大片农田都被改建为养殖池,自然湿地在减少,人工湿地在不断增加,导致七里海湿地景观类型日趋单一,生物多样性明显减少。
Abstract: The Qilihai ancient lagoon wetlands locate in the southwest of Ninghe county in Tianjin. It is the core part of National Nature Reserve of Tianjin Ancient Seacoast and Swamp. It is also one of the lagoon wet- lands which were formed from the regression in Holocene. The geological background of the Qilihai wetlands has been analyzed in this paper. Controlled by the Jiyun River Delta, Chaobai River Delta, Cangdong fracture, Liangzhuang fracture and Lutai fracture, the Qilihai wetlands had shrank for 3 times. It shrank quickly in the southwest, slowly in the northeast of Qilihai ancient lagoon wetlands. The formation and evolution of the Qili- hai ancient lagoon wetlands over 5000-year before present were also analyzed in the paper. There are 4 paleo- coast lines which located in Ninghe county. The paleocoast lines became younger and younger from the north to the south of Ninghe county. There are paleoridges and paleooysters between every two paleocoast lines. The peleocoast lines, paleoridges and paleooysters proved the alternation of land and sea which impacted the for- mation and evolution of the Qilihai ancient lagoon wetlandsdirectly. Taking the topographic maps and remote sensing images during 1950-2005 as the data sources and using geographic information system technology,the spatial and temporal changes of the Qilihai ancient lagoon wetlands were studied in this paper over the past 85 years. The factors, which impact on the evolution of the ancient lagoon wetlands and eco-environ- ment, were analyzed in accordance with historical statistics information and observation data. The results showed that the area of the wetlands changed remarkably which decreased at least 60 km2 during the past 85 years. The evolution of the wetlands has mainly gone through 3 stages in accordance with different dominant factors. During the period of natural evolution from 1926 to 1950, the ancient lagoon wetlands took nature evolution mainly. The Qilihai ancient lagoon wetlands consisted of Houhai, Qulihai and Qianqilihai in 1926. Based on the remote sensing image of 1950, the wetlands still kept original wetland landscape. During the pe- riod of treatment from 1950 to 1981, the wetlands were divided into East Qilihai and West Qilihai by Chaobai River and the Houhai was disappeared in 1976. The area of the wetlands was 108 km2 (the area of Qianqilihai and Houhai only) in 1950 and 48.7 km2 in 1976. During 1982-2005, a large scale cultivated activities caused a sharply reduction of lagoon area which was down to 43.1 km2 under the backdrop of construction of the dam. The natural wetlands surrounding the lagoon have basically disappeared in 2005 and gradually replaced by ar- tificial wetlands. The area of natural wetland of the Qilihai lagoon decreased, which resulted in the habitats of various wildlife were compressed massively. Influenced by natural and human being factors, the degradation characteristic of the wetlands were atrophy of wetland area, the scarcity of water resources and biologic diver- sity decrease. The ecological environment of the wetlands got worse. The best way of protecting the ecologi- cal environment of the wetlands was solving the water resources and protecting the ecological water demand of Qilihai ancient lagoon wetlands.
出处
《湿地科学》
CSCD
北大核心
2012年第2期181-187,共7页
Wetland Science
基金
"天津七里海古海岸与湿地地质遗迹调查与保护"项目(国土房任[2011]2号)资助
关键词
古泻湖
七里海
湿地
遥感
环境演变
ancient Lagoon
Qilihai
wetland
remote sensing
environmental evolution