The Ecological Consequences of Socioeconomic and Land-Use Changes in Postagriculture Puerto Rico

S the origin of agriculture, the human population and human consumption of resources have increased steadily throughout the world. As a consequence, forests and other natural areas have been transformed into agriculture, pastureland, and cities. Land-use and land-cover change (LUCC) represents one of the most important components of global environmental change. Widespread effects of LUCC include habitat loss and fragmentation, soil degradation, species introductions, and changes in vegetation. Indirectly, LUCC affects the interactions between the biosphere and the atmosphere (through alterations of biogeochemical cycles) and between ecosystems and cultural systems (Turner et al. 1990). Land-cover change is very intense in tropical developing countries that are characterized by agriculturebased economies and rapidly increasing human populations (Watson et al. 2001). Consequently, most research on the ecological implications of LUCC in the tropics focuses on the dominant pattern of deforestation and fragmentation (e.g., Houghton 1999, Laurence et al. 2002), which is driven by the prevailing socioeconomic and demographic factors. The most recent predictions, however, indicate that the world’s human population will stop growing before 2100 (Lutz et al. 2001), and current trends of economic globalization promote agriculture intensification, industrialization, and migration of rural population to urban areas.A potential consequence of these trends is that areas of marginal agriculture will be abandoned, leading to forest recovery. Forested areas are already expanding in developed countries where the economic base has shifted from agriculture to industry (Ausubel 1996). Although most forest recovery is occurring in temperate ecosystems (e.g., Foster et al. 1998), some examples exist in tropical countries where manufacturing is replacing agriculture, such as Taiwan (Chang and Tsai 2002) and Puerto Rico (Franco et al. 1997, Rudel et al. 2000). The recent Puerto Rican history, characterized by a major shift from agriculture to manufacturing in the late 1940s (Dietz 1986), provides an excellent opportunity to study the ecological consequences of socioeconomic changes associated with economic globalization in a tropical environment. In this article we describe how economic changes have affected the