Despite today’s widespread reference to sustainability, initiatives are still quite incipient. Ecovillages are communities that carry out an array of sustainable practices and aim to influence society as models for alternative lifestyles. The goal of this paper is to analyze the meanings associated with these communities in the academic literature and their relevance to sustainability debates. Regardless of the conceptual imprecision of the term ‘ecovillage’ and important challenges and limitations regarding their social role in society, ecovillage initiatives (many that are educational) have propagated by diffusing alternative ideas and practices throughout society. They are increasingly linked with other movements and social institutions, functioning as key nodes in sustainability-oriented networks. As they promote concrete actions in the construction of societal alternatives, ecovillages significantly contribute to efforts of rethinking sustainability.

It is often very difficult to align sustainability-related discourse with practices, partly due to the compartmentalized treatment of sustainability’s dimensions. Building on existing literature, this paper seeks to analyze the way those dimensions are worked out in the practices of ecovillages, a kind of community explicitly oriented towards sustainability. We observe that ecovillages view sustainability in a systemic perspective, adopting a multidimensional and integrated approach. That is apparent in the fact that their practices simultaneously present functions in various dimensions revealing the latter’s interdependency. The so-called ‘social sustainability’ (including political, economic and cultural aspects) involves far more significant difficulties than ‘ecological sustainability’ and it may even render the continuity of such communities unfeasible. The experience of ecovillages suggests that social sustainability constitutes the very foundation of ecological sustainability, insofar as ecological practices are necessarily mediated by complex social relationships.

ResumoUm importante mas ainda pouco compreendido fator de influência na dinâmica florestal em áreas montanhosas é a topografia. O objetivo deste estudo foi analisar a distribuição espacial de manchas de gramíneas no fragmento de floresta atlântica urbana que recobre o Maciço da Tijuca, levando em conta os aspectos topográficos. Foi feito um mapeamento de uso e cobertura com base em ortofotos aéreas de 2004, e, com o auxílio de um Modelo Digital de Elevação, foram realizadas algumas análises espaciais (mensuração de área em superfície real, orientação de encostas, radiação incidente e posição topográfica) e temporais (comparações entre mapeamentos realizados em 1972, 1984 e 1996 e comparações entre ortofotos de 1999 e 2004). As manchas de gramíneas e de vegetação arbóreo-arbustiva apresentaram um forte padrão de distribuição espacial, concentrando-se nas encostas voltadas para o Norte e nos divisores e altas encostas, o que foi atribuído, respectivamente, à maior incidência de radiação solar nas encostas Norte e à convergência dos fluxos de água e nutrientes dos divisores para os fundos de vale. Temporalmente, notou-se uma ligeira tendência de aumento das áreas de gramíneas nas zonas de divergência de fluxos e diminuição nas zonas de convergência. Observou-se ainda que, dentre as bacias de segunda ordem que possuíam gramíneas em 1999, 37% mostraram significativa transformação para formações arbóreo-arbustivas em 2004 -o que provavelmente se deveu em parte aos reflorestamentos realizados nestas áreas. palavras-chave: Manchas de gramíneas; topografia; regeneração florestal. AbstractOne important but seldom studied factor of influence on forest dynamics in mountainous areas is topography. The purpose of this study is to analyze the spatial distribution of grass patches in the fragment of urban forest that recovers Tijuca massif, considering topographic factors. We elaborated a land cover and use map based on aerial ortophotos taken in 2004. Then, with the support of a Digital Elevation Model, we performed a series of spatial analyses (real surface area mesurements, slope orientation, incident radiation and topographic position) and temporal analyses (comparations between previous 1972, 1984 and 1996 mappings, and between 1999 and 2004 ortophotos). Grass and shrub-tree vegetation patches presented a conspicuous distribution pattern, concentrating at north-facing slopes and at ridges and upper slopes, facts that have been www.ugb.org.br