The South American temperate and sub-Antarctic forests cover the longest latitudinal range in the Southern Hemisphere and include the world's southernmost forests. However, until now, this unique biome has been absent from global ecosystem research and monitoring networks. Moreover, the latitudinal range of between 40 degrees (°) south (S) and 60° S constitutes a conspicuous gap in the International Long-Term Ecological Research (ILTER) and other international networks. We first identify 10 globally salient attributes of biological and cultural diversity in southwestern South America. We then present the nascent Chilean Long-Term Socio-Ecological Research (LTSER) network, which will incorporate a new biome into ILTER. Finally, we introduce the field environmental philosophy methodology, developed by the Chilean LTSER network to integrate ecological sciences and environmental ethics into graduate education and biocultural conservation. This approach broadens the prevailing economic spectrum of social dimensions considered by LTSER programs and helps foster bioculturally diverse forms of Earth stewardship.