The environmental history of Latin America has become the focus of a number of scholars, starting in the later years of the twentieth century. But historians earlier than that recognized that the environment played a major role in the region's history. Environmental history more generally has developed as a specialized, yet broad and diverse field. According to one assessment of the field, scholars have mainly been concerned with "three categories of research: colonialism, capitalism, and conservation" and the analysis focuses on narratives of environmental decline. There are several currents within the field. One examines humans within particular ecosystems; another concerns humans’ cultural relationship with nature; and environmental politics and policy. General topics that scholars examine are forestry and deforestation; rural landscapes, especially agro-export industries and ranching; conservation of the environment through protected zones, such as parks and preserves; water issues including irrigation, drought, flooding and its control through dams, urban water supply, use, and waste water. The field often classifies research by geographically, temporally, and thematically. Much of the environmental history of Latin America focuses on the nineteenth and twentieth centuries, but there is a growing body of research on the first three centuries (1500-1800) of European impact. As the field established itself as a more defined academic pursuit, the journal Environmental History was founded in 1996, as a joint venture of the Forest History Society and the American Society for Environmental History (ASEH). The Latin American and Caribbean Society for Environmental History (SOLCHA) formed in 2004. Standard reference works for Latin American now include a section on environmental history. Early scholarship Works by geographers and other scholars began focusing on humans and the environmental context, especially Carl O. Sauer at University of California, Berkeley. Other early scholars examining humans and nature interactions, such as William Denevan, Julian Steward, Eric Wolf, and Claude Lévi-Strauss. In terms of impact, however, Alfred W. Crosby's The Columbian Exchange (1972) was a major work, one of the first to deal with profound environmental changes touched off by European settlement in the New World. It examines a range of impacts of Europeans on Latin America, especial Page information ly during the period of European Contact, including epidemic disease and the importation of Old World animals and plants and the development of large-scale ranching and agriculture. He further developed the argument in Ecological Imperialism (2004). Archeologists such as Richard MacNeish conducted fieldwork uncovering the origins of