The purpose of this study is to improve environmental sustainability by identifying the most sustainable/least fragile of the three major wildlife conservation access models-open, government, and private-under varying environmental and socioeconomic conditions. The private access model is the most sustainable of the three major conservation models because it provides the best information and incentives to balance the needs of humans and wildlife, maintain general wildlife habitat, and adapt quickly to changing environmental and/or socioeconomic conditions. Government-controlled access, however, can be employed as a model of last resort if the private access model shows signs of failing to protect specific species from local extirpation or extinction, which it is most likely to do for migratory species, species with close commercial substitutes, and species with no direct commercial value. Government regulators may also be needed to enforce property rights arrangements like catch shares and to monitor resources that remain open access in case socioeconomic or environmental conditions change sufficiently to trigger the tragedy of the commons. Most treatments of wildlife regulation default to various iterations of the government access model and fail even to consider the costs and benefits of private and open access models. The analysis here instead shows the conditions in which each conservation access model is most appropriate: open when a resource is in high supply and low demand, private most of the time, and government when the others fail to slow resource depopulation/depletion.