Liangzhu culture
The Shijiahe culture ended around 2000 BC, about the same time as Liangzhu. However, unlike the Liangzhu culture, which completely disappeared, Shijiahe seems to have had a drastic decrease in population. Some scholars believe the decline was a result of warfare with the Longshan culture, which was expanding from the north. Other possible reasons are flooding, collapse of social order or a combination of these factors. From 4200 cal BP, severe drought eroded the economic foundation of rice-cultivation.