This thesis offers an empirical analysis that critically assesses and expands the concept of “ontological politics” as a tool for understanding environmental conservation practice. It takes the case of páramos conservation in Colombia, a high mountain ecosystem located above 2600 mts altitude. The area is known for its vast biodiversity, its vital role providing water and for the presence of communities of “campesinos” (peasants in english) who fled to these remote places to escape Colombian political violence in the countryside during the 20th century.  Since 2010 the Colombian state has initiated a series of measures to conserve páramos. But it has become apparent that the presence of campesinos in páramos does not seem fully to fit with the conservation goals set by the Colombian government. Taking this as its starting point, the thesis reports on a multi-sited ethnography among campesinos and scientists (biologists and geographers), with the aim of determining to what extent the practices of all those involved can or cannot produce a páramo spacious enough for diverse forms of living. The thesis uses these empirical materials to argue that four key dimensions of ontological politics need to be respecified to provide a method for both analyzing and intervening in conservation practice: boundary-making, space, ontological differences, and intervention. These dimensions, the thesis argues, are central for the twofold task of reconfiguring ontological politics as a tool for social analysis and interrogating the forms of politics that it enables in re-search practice.