A benefit of voluntary permit retirement coupled with adding roadless areas to the existing wilderness in the Greater Gila Bioregion would be that vital, natural processes such as predation and fire would be permitted to occur on larger landscapes and fulfill their roles as ecological regulators. Efforts are underway to restore natural fire regimes to the fire-dependent forest and grassland ecosystems of the Greater Gila Bioregion, but top carnivores that exert ecosystem-regulating influences on native herbivores are acutely lacking. Other than mountain lion, black bear, coyote and bobcat, the native carnivores of the Greater Gila Bioregion are absent in ecologically meaningful numbers. Scientific research increasingly indicates that carnivores play an important controlling role in an ecological system. The best example of this control is carnivore eradication and reduction that has simplified systems and reduced biodiversity, largely by eliminating their keystone role of ungulate predation. When deer and elk numbers explode in the absence of a key carnivore such as the Mexican gray wolf, vital plants like willow along streams and rivers can be suppressed and thus the entire riparian ecosystem impoverished. The restoration of these natural processes is especially important to Southwestern ecosystems that will need to adapt in the face of climate change.