Although the medium-height mountainous areas of Kopetdag, Badkhyz, Balkhan and Kugitang occupy only 2 per cent of the territory, they harbour two thirds of the country’s species. The alluvial plain of the Amu Darya River in the north-east includes significant tugai forests. There are also lakes (many temporary) and smaller rivers, most of which end blindly in the Karakum Desert or are entirely used for irrigation. Anthropogenic landscapes include oases and the 1,445 km Karakum Canal.