Centuries of slash-and-burn agriculture have caused forested areas to be replaced by savanna woodland, grassland, or brush. During 1981–85, some 36,000 ha (89,000 acres) of land were deforested each year. Between 1990-1995, Guinea lost an average of 1.14% of its forest and woodland area each year. Mining, the expansion of hydroelectric facilities, and pollution contribute to the erosion of the country's soils and desertification. Water pollution and improper waste disposal are also significant environmental problems in Guinea. In 1994, water-borne diseases contributed to an infant mortality rate of 145 per 1,000 live births. The nation has 226 cubic kilometers of renewable water resources with 87% used in farming activity. Only about 35% of the people living in rural areas do not have pure water. Guinea's cities produce about 0.3 million tons of solid waste per year. As of 2001, 11 of Guinea's 190 mammal species and 12 of its 409 bird species were endangered, as well as 3 types of reptiles, 1 amphibian, and 29 of the nation's plant species. Human encroachment and hunting have reduced Guinea's wildlife, especially its large mammals, and overfishing represents a threat to the nation's marine life. A nature reserve has been established on Mt. Nimba. Threatened species include the African elephant, Diana monkey, and Nimba otter-shrew.