Based on an empirical survey of rancher commitment in environmental programs in Southern Arizona, this paper analyzes the evolution of rangeland conservation practices and more broadly of natural resources management in semi-arid areas of the American West. Far from the image of the cowboy conquering and destroying the wilderness, which some environmental organizations still convey, it shows how ranchers get involved in ecological practices, enabling us to consider their social (re)valorization as conservation entrepreneurs empowered to co-produce ecological knowledge. In this perspective, the survey shows, (1) the way in which nature conservation programs no longer valorize the planning of ‘wilderness areas’, but rather collaborative programs based on working landscapes and, (2) the conditions for valorizing a kind of cowboy ecology that might contribute to the renewal of natural resource management and practices dedicated to nature conservation. The scientific originality of this paper is thus to outreach a ‘political ecology of ranching’, showing how the valorization of rancher knowledge and know-how fits into the renewal of rangeland ecological science and socio-economic transformations. It demonstrates that this ecological acknowledgment of ranching is due to the specific knowledge of the ranchers, which contributes solutions for the preservation of biodiversity that seem adapted to the environmental constraints of semi-arid areas. More broadly, it invites us to revisit the way in which cowboy ecology is now supported by administrative agents (and even environmentalists) to face ecological risks other than grazing.