With human settlement, agriculture has taken root across most of the fertile basin and reduced the original forest to small patches on hills and mountains including Mount Emei. The extensive ridges in the eastern Sichuan Basin preserve elements of the original forests. A greater variety of natural landscapes and wildlife have been at least partially preserved in the mountains surrounding the basin where human settlement has been less intensive. The natural ecosystems of these mountains have been classified by the World Wildlife Fund as the Qionglai-Minshan conifer forests to northwest and the Daba Mountains evergreen forests to the northeast and east.