The process of conversion from wetland into cropland(CWC) is the main feature of land cover change in Sanjiang plain in the past 50 years.

• 到2005年,除洪河自然保护区及靠近黑龙江和乌苏里江边缘地区外,研究区的大部分都成为耕地景观高梯度分布区。