Rural-urban migration

A year ago T. Mitchell Aide and H. Ricardo Grau wrote in Science ("Globalization, migration, and Latin American ecosystems"):

Sixty years ago, most of the mountains of Puerto Rico were [...] treeless, but forest recovered as the economy shifted from agricultural to industry and services. A similar process has occurred in Dominican Republic during the last 20 to 30 years; an increase in job opportunities in the cities associated with expanding tourism and textile industries stimulated rural-urban migration and forest recovery on the abandoned lands in the mountains. Other areas in Latin America are experiencing similar landuse dynamics as socioeconomic globalization extends its effects.

S. Joseph Wright provides an update for Brazil in the latest issue of Trends in Ecology and Evolution ("Tropical forests in a changing environment"):

In the Brazilian Amazon, for example, the rural:urban income ratio averages 0.6, the percentage of the population living in rural settings declined from 57% to 40% in 16 years, the number of rural establishments declined by 23% in 11 years, and secondary forest has reclaimed 31% of the once deforested land. More generally, rural–urban migration is contributing to the intense urbanization of most tropical countries, former agricultural lands are being abandoned, and secondary forests are becoming more widespread.

Aide and Grau extract an important lesson:

In rural areas, an important conservation strategy has been to invest in community-based sustainable development projects. These projects have had limited success in improving socioeconomic conditions and may delay rural-urban migration and ecosystem recovery.