Authors: Buchadas, Ana; Qin, Siyu;Kuemmerle, Tobias ;

Land-use frontiers, such as agriculture expanding into natural forests in the Global South, continue to be a major driver of biodiversity loss and frequently trigger conservation responses. With the increasing geographic footprint of area-based conservation, land conservation can be considered a major land use itself. Using tools and concepts from Land System Science – the field studying land use as a social-ecological system – therefore should provide opportunities to better understand the patterns, actors, and drivers of land conservation. Here, we propose that land conservation can be usefully examined through the concept of frontiers, and specifically three different perspectives related to frontiers. First, conservation can be defined as efforts to slow or halt other frontiers (e.g. deforestation). Second, expanding land conservation could be described as a frontier process itself, leading to similar institutional and cultural reorganization, as well as conflict (e.g. green grabbing). Finally, frontiers can be viewed as spaces where multiple land uses, including conservation, interact. Bridging the disciplines of Land System Science and Conservation Science, as we propose here, could enable a deeper consideration of the social-ecological contexts in which conservation occurs, and thus support better conservation planning.