全新世中期以来西辽河流域动物地理与环境变迁

自全新世中期以来 ,西辽河流域动物群的种类成分有很大变化。全新世中期 ,野猪和鹿科动物是这里最主要的大型食草动物。公元初期 ,野马等草原动物占有一定地位。中世纪的辽代时期 ,鹿科动物成为这里最主要大型食草动物 ,同时 ,有适应沼泽环境的麋鹿。直到清代初期 ,野马在动物群中还占有一定地位。清代中期 ,大型食肉动物虎、豹、熊分布较广泛 ,清代晚期 ,其分布迅速减少直至消失。动物地理的变化在一定程度上反映了环境的变化。

Changes of environment and animal geography of the West Liaohe River Basin since middle Holocene

The West Liaohe River Basin is located to the east of Inner Mongolia of China and lies approximately between 117°00′～123°30′E and 42°00′～45°00′N. This region is a transitional zone of forest, forest steppe and steppe. According to researches on many archaeological sites of middle Holocene found in this region, wild pig ( Sus scrofa ) occupied a dominant position in the wild herbivores, and the bones of David's deer( Elaphurus davidianus ) was found in individual site.Wild pigs normally dwell in coniferous forest and mixed coniferous and broad leaved forests.This means forests played an important role in vegetation in middle Holocene in this region. And in the beginning of the Christian Era, wild horse ( Equus przewalskii ) was the main local product. This means that the steppe might have expanded. But in the Medieval era (during the beginning of the 10th to the beginning of the 12th century A.D.), the nomadic Qidan nationality established powerful Liao Dynasty, and there were a lot of documents about the West Liaohe River Basin. During this period, the David's deer( Elaphurus davidianus ) was recorded by many travelers, but however,no record of wild horse could be found in all historical documents during this period. This means that the forests had been expanded. And in the beginning of the Qing Dynasty (the 17th century AD), the wild horse was recorded as one of the local products. This means that the steppe could be expanded, and the forest reduced. And before the mid Qing Dynasty (the 18th century AD), tiger, beer and leopard were extensively distributed.However, after the mid Qing Dynasty, especially after the end of the 19th century, tiger and leopard became less and less and could not be found in any historical documents. The changes of animal geography before the 18th century were the result of natural changes, because the population was very sparse during this period of time. However,the changes of animal geography after the 18th century were induced by human activities, because the agricultural population migrated massively from the Yellow River Basin to the West Liaohe River Basin plus rapid population growth after the mid Qing Dynasty.This resulted in forest reduction and steppe expansion.