The Study Of Changes Of Natural Environment And Cause In The West Liao River Basin During The Qing Dynasty

In this thesis, according to the degree of change, we divided the natural environment change of the West Liao River Basin into 3 stag es, that is, the first stage is from the first year of Shunzhi to the tw elfth year of Qianlong( 1644 ~1747),during this stage,the natural environment of the W est Liao Rive r Basin was be tter than th e late of Ming Dynasty. The second stage is from the thirteenth year of Qianlong to the 27 th year of Guangxu(1748~1901).In this stage, the environm ent of the West Liao River Basin was severely damaged. The third stage is from 28 th year of Guangxu to the end of Qing Dynasty(1902~1911).In this stage, the environm ent of the West Liao River Basin was worse than before.Through our investigation, we found that th e natural environment of the West Liao River Basin in Qing Dynasty was in a trend of deterioration. The main performances are vegetation degradation, land de sertification, animal species extinct, water system shrinking, etc.while the m ain reason is,w ith the continuous im migration of Han agricultural population,the arable land area was expanded a nd agriculture lifestyle was adopted by the local residents. In ad dition to these factors, the Qing Dynasty was in the little ice age, the co ld and dry climate also have a influence on the local environment.However,within the two factors,the human factors are the main and first factors and the natural factor is the second one.The reason of the natu ral environment change of the West Liao River Basin in the three stages are not all the sam e, that’s why we divide it in to three stages to alynize.In other words, we should find out not only the ge nerality but also the difference of them, such as, the different policy of the authority druing the three periods.