Abstract : The “environmental crisis”, made public through various damages and threats that challenge the survival of our species (Larrère, 1997), urges our societies to include beings and phenomena that are not solely human into our moral sphere. Also, it requires to re-think the way we plan our activities in spaces than we share de facto with a large number of entities. This doctoral research focuses on “natural areas” management policies. Park and wilderness managers have to comply with an increasing diversity of norms and rules, they have to “ecologize” the way they do things. But caring for “nature” or the environment can hardly exclude the well-being of humans. We analyse four management projects labelled as “ethical” or “responsible” on different terrains, from Grenoble city parks (France) to Mt Jefferson Wilderness (Oregon). The responsibility concerning the future of these “natural areas” appears to no longer be only that of the managers: it is distributed along a chain of humans and non humans. People in charge of these areas count on many individuals and things. Their actions can be considered as experiments that are altogether scientific, politic and moral (Latour, 1995; Hache, 2011). They build site-specific precarious compromises following an ethics of coping. In this context, parks and wildernesses cease to be relevant scales of action and other socio-spatial forms emerge. A geography of heterogeneous associations (Murdoch, 1997) seems to offer one interesting means of following the links operating in these attempts to build a common world.