This paper is part of a project exploring how community-led sustainability transition initiatives balance the realization of alternative livelihoods, while at the same time engaging with previously existing political, economic and cultural structures. It uses a case study approach to analyse how the following initiatives engage external practitioners and scholars, as well as the public sphere, in transdisciplinary communities of practice aimed at ecological, economic and regulatory innovation: - “Tamera – Healing Biotope I”, an ecovillage and self-defined “Peace Research and Education Centre” in southwestern Portugal; - Esperança-Cooesperança, a Solidarity Economy commercialization network in the state of Rio Grande do Sul, Brazil; - Cooperativa Integral Catalana, an “Open Cooperative” of producers and consumers, structured around a basket of social and crypto currencies, managed by virtual and presential assemblies of participants. Based in Catalonia, Spanish State. Based on a systems thinking approach, informed by fieldwork carried out between 2014 and 2017, this paper compares and contrasts the processes of resource mobilization, knowledge and technology transfer, as well as the normative and political criteria informing them, underlying the construction of communities of practice in each case study. It also analyses how such processes impact, in these case studies, what scholarship perceives to be a major vulnerability of communitarian endeavours: the tendency for the emergence of internal hierarchies and exclusionary mechanisms, as well as reduced creativity due to pressures for ideological conformity, in the form of: - hierarchies of rank, in terms of access to “voice” in decision-making and resources; - the emergence of formal and informal barriers to the inclusion of new participants in the projects, or opportunities for external actors to participate in their activities, based on economic, identity-based, ideological or political criteria. The paper concludes with thought points for future dialogue among the ecovillages, solidarity economy and virtual commons-based peer production movements on how to mobilize communities of practice for the promotion of more inclusive, socially just and creative sustainability transitions.

--