Our Plundered Planet

acres Africa agricultural Amazon basin America animals apes Arctic Ocean Australia bacteria basic become cattle causes cent century chemical cities civilization collective farm consequently conservation continue covered crops cultivation damage desert destruction developed Dust Bowl early earth effect elements erosion exist fact fertile forests fossil grasslands grazing Greece groups growing growth habitable happened human increasing industry insects land resources livestock living things mammals man's ment Mesta methods millions mineral misuse mountain nations nomadic North numbers organic overgrazing plants podsol point of view Pontine Marshes population present problem productive land productive soil protect protozoa public lands rabbits races rainfall rains reasons recent regions result rivers Russia sheep situation slopes South South America Soviet square miles subsistence survival terraces thought tion topsoil total land area trees tsetse fly ungulates United valley vast Volga Western wild