The Preliminary Study On The Environmental Changes Of Jialing River Valley In Late Holocene

The Historical Natural Geograghy research of Jialing River Basin presents quite an unbalanced situation, though it has made plentiful achievements over the past few decades. Especially in the development of the basic historical documents and textual research, jialing river upstream of natural geography and ecological environment, regional history, history of the middle and lower reaches of the jialing river basin area disaster geographical aspects of research works relatively substantial, from one side to reflect the jialing river basin of the historical geography research closely with the reality of the society needs to keep pace with The Times characteristics.At the same time the history of the basin geography research present a serious imbalance, some basic issues remains unsolved, such as the headwater, the historical weather, the quantization of historical hydrology and the Environmental Archaeology of the whole basin.On research methods, tend to be in the field of history research often stay in the description of the static level, and this kind of description can not meet the needs of the present study.This article attempts to the historical literature record, as compared with the natural scientific evidence recovery jialing river basin since late holocene environment changes, summarizes the law of environmental change. Jialing river basin located in the junction of three natural area, because our country three natural zones in the timing of the alternation of historical climate changes in temperature difference, so the jialing river basin in history has a special meaning of climate change. This paper is trying to restore the environmental changes of Jialing River Basin from the late Holocence and summarize the rules by comparing historical documents with the evidences of natural science. This paper figures that the weather of Jialing River Basin changed from cold to warm in Song Dynasty, and the exact time is between1170AD and1172AD. There are three ice age s in the Little Ice Ages of Ming and Qing Dynasty:1510-1549AD,1620-1659AD and1870-1899AD. This paper studied the distribution and variance of historical plants and animals based on several separate main landscape areas in this basin, and focused on the "combination" of different species instead of the distribution of certain single species.The environmental restorance in this paper basically depends on historical documents. Although the omissions of such documents is inevitable, we could eliminate the false, cling to those reliable material, synthesize correlative problems and finally reproduce the historical ecological condition.