The natural environment in Moldova suffers from the heavy use of agricultural chemicals (including banned pesticides such as DDT), which have contaminated soil and groundwater. Poor farming methods have caused widespread soil erosion. In 1996, Moldova's industrial carbon dioxide emissions totaled 12 million metric tons. As of 2001, 1.4% of Moldova's total land area is protected. Two out of 68 mammal species and 7 out of 177 breeding bird species were threatened. Threatened species include the European bison, European souslik, and the great bustard.