摘要
在地质因子、气候因子和人为干扰因子等的共同作用下,三江平原形成大量的孤立湿地。新构造运动的沉降或隆起间接地影响到孤立湿地的形成和发育,质地黏重的第四纪沉积物为孤立湿地的形成创造了有利的环境条件,古冰丘融化和古河道变迁直接导致孤立湿地的形成。气候变化(气温逐渐升高,降水量逐渐减少)和水文条件的改变(水位降低)造成湿地生态系统的逆向演替和退化,湿地退化后以"孤立湿地"形式残存下来。自20世纪50年代以来,在三江平原开展了几次大规模的农业开发活动,导致大面积连片湿地的破碎化,在农田中的地势较低处残留下来的沼泽,形成大量的孤立湿地。按孤立湿地形成和发育的地貌部位,将孤立湿地划分为阶地碟型洼地型、古河道型、河漫滩型、湖滨型和山前倾斜平原型孤立湿地。其中,分布在河流阶地地貌中的孤立湿地数量最多;按孤立湿地的形态可以分为碟型、线型和不规则型孤立湿地;按孤立湿地与土地利用类型之间的关系可划分为自然湿地中的孤立湿地、林地中的孤立湿地、居民用地中的孤立湿地、水田中的孤立湿地和旱田中的孤立湿地,其中,旱田中的孤立湿地数量最多。孤立湿地的结构和功能多样,生态环境效应明显,应对其进行合理保护与规划。
A large number of isolated wetlands in the Sanjiang Plain are formed under the combined action of the geological, climatic and human disturbance factors. The subsidence and uplift of new tectonic movement had affect the formation and development of isolated wetlands indirectly, and formed different types of isolat- ed wetlands. The Quaternary sediments of heavy clay created favorable environmental conditions for the for- mation of isolated wetlands, the sedimentary rhythm provided plenty of water for the formation of isolated wetlands. Climate change such as temperature increased gradually and precipitation decreased gradually, had caused degradation of the wetlands and area of the wetlands reduced gradually, had created necessary condi- tions for the formation of the isolated wetlands. Melting of ancient ice mound, ancient river change and hu- man reclamation activities led to the formation of the isolated wetlands directly. According to classification standards of the formation and landform development part of the isolated wetlands, divided the isolated wet- lands into the terrace dish and hollow isolated wetland, ancient river isolated wetland, flood land isolated wet- land, lakeside isolated wetland, piedmont sloping plain isolated wetland and so on, the number of the isolated wetlands distributed in the river terrace got the most, and accounted for 57.76%. According to the shape of the isolated wetlands divided the isolated wetlands into dish shape isolated wetland, line isolated wetland and ir- regular shape isolated wetland. According to the relationship between the isolated wetlands and the land use types, divided the isolated wetlands into the isolated wetlands in natural wetlands, forest, residential, paddy fields and dry farmlands, and the number of the isolated wetlands in the dry farmlands accounted for 49.3% of total number of the isolated wetlands. Isolated wetland is one of the main types of the wetlands in Sangjiang Plain, the structure and function of the isolated wetlands were diversity, the ecological environmental effects were obvious, and human should provide reasonable protection and planning.
出处
《湿地科学》
CSCD
北大核心
2014年第2期141-147,共7页
Wetland Science
基金
国家自然科学基金项目(41071037)
教育部新世纪优秀人才支持计划项目(NCET-12)
吉林省教育厅项目(吉教科合字2013第201号)资助
关键词
孤立湿地
类型
成因
三江平原
isolated wetland
type
cause
Sangjiang Plain
