In this paper I describe processes and impacts of collective action by mobile pastoralist communities, and of external support strategies to strengthen local institutions and cooperation In Mongolia southern Gobi. The need for pastoral mobility triggered the processes leading to community organization, and the emergence, or re-emergence, of local informal institutions. Their growing role in natural resource management, conservation, rural self-governance and service delivery, and the onset of self-organization and scaling-up without external input may suggest success in terms of developing institutional capacity, and of strong local ownership of donor supported activities. Keywords: livestock mobility, collectives, participatory monitoring, selfgovernance, nomadic livestock management.