Our changing planet encompasses a rich mosaic of landscapes differently transformed by humans. In its current state, this mosaic includes the last “wilderness-development frontiers”, areas where expanding global forces are rapidly and massively transforming remote landscapes that have so far remained largely free from impacts of modern humans. Appreciation of these undeveloped landscapes requires ethical values differing from those driving cultural globalization and promoting intensive land use. We propose that greater integration between ecological science and environmental ethics will stimulate new research, policy, and conservation strategies applicable to these rare and valuable ecological ‘frontiers’. Within this framework, our session aims to advance the development of the interface between ecology and ethics by focusing on the remote archipelago region of southwestern South America, an extensive area including the largest remaining tracts of temperate and subantarctic rainforest in the southern hemisphere. This remote territory is changing rapidly as a result of expanding salmon-farms, large hydroelectric projects, new access roads, and massive tourism. On the other hand, the same region houses innovative but incipient conservation projects, including the recently created Cape Horn Biosphere Reserve, large private conservation initiatives, and regionally-based interdisciplinary research-education-conservation centers (e.g., Senda Darwin Biological Station and Omora Ethnobotanical Park). Paradoxically, remote areas that host biotas and ecosystems in “pre-industrial” condition, which can serve as baselines to understand, predict, and mitigate human impact, are still poorly equipped for research and monitoring compared to highly anthropogenic landscapes in developed regions. This session brings together regional visions from southern South America and international perspectives from North American and European ecologists and philosophers, including leaders within the wilderness-development debate. Such interdisciplinary analysis of concepts and experiences from southern South America can also provide useful insights for conserving “development-wilderness frontiers” in our rapidly changing world.