近百年来西辽河流域土地开垦及其对环境的影响

西辽河流域是国家实施西部大开发战略的重点地区之一,属于典型的生态脆弱区。研究流域的土地开发过程及其对环境的影响是探讨区域土地退化根源、寻求合理的区域土地利用结构的必由之路。本文考察了1902～1990年间西辽河流域土地开垦的时空过程,并指出正是由于不合理的人类活动,对西辽河流域的环境产生了重大的影响,造成了植被的破坏、野生动物濒临绝迹、水土流失和土地退化的加剧。

The land reclamation and its influence on environment in West Liaohe Basin from 1902 to 1990

West Liaohe Basin is one of the key regions in the West development strategies implemented by the Chinese Government,and its eco-environment is vulnerable.Study on land reclamation and its influence on environment is the only way to explore the cause of land desertification and seek for the proper pattern of land use. (1)This paper examines changes of the land reclamation in West Liaohe Basin in about 100 years(1902-1990).At the end of the Qing Dynasty,it had no land to open up in the south of West Liaohe,but areas of plowland got increased in counties and Qis(banners) in the north of West Liaohe.In the period of Republic of China,much plowland was turned into wasteland in the south of West Liaohe,but in the north of West Liaohe,a great amount of grassland was developed into arable land.After liberation(1949),because of unreasonable land policies,all grassland was almost opened up completely. (2)Above all,natural environment in West Liaohe Basin has been greatly influenced.First,vegetation was destroyed,so the virgin forest of the Qing Dynasty now becomes the secondary forest dominately composed of mountain polar and white pirch,and the thick forest gets the thin one.Secondly,wild animals lost their natural living environment owing to vegetation destruction,so small animals such as rabbits,pheasants,crows,pied magpies and so on,now become rarer and rarer besides of macro-animals being extinct. (3)Soil erosion happened in the Qing Dynasty,lately reclamation took place at a large scale at the end of the Qing Dynasty,much plowland changed into wasteland in Republic of China,and extensive reclamation after liberation makes it on the rise.