Environmentalists in Rio de Janeiro's Niteroi neighborhood say unrestricted real estate development and the growth of favelas are destroying the city's fragile ecology, according to this article, in Portuguese, from the Jornal do Brasil.)
Here's a summary, courtesy of the good folks at americas.org:
The growth of favelas threatens Niteroi: Governing bodies denounce irregular occupation and real estate speculation in nature reserves.” Increasingly worried by the degradation of ecological reserves in Niteroi, environmentalists have begun to denounce the transformation of these protected areas into slum neighborhoods. Environmentalist Gerhard Sardo, the regional coordinator of the Permanent Assembly of Entities in Defense of the Environment of the State of Rio de Janeiro (Apedema), blaims both the real estate business and the spread of favelas for the growing environmental destruction. He points out that, whereas virtually nothing can stop the spread of slums, environmental abuse on the part of real estate projects can be controlled by fines and punishments.