Initially, the Endangered Species Act created a preservation pattern that was oriented species by species. It made for a complex but not very efficient system.
The Coachella (Valley) plan is considered to be one of the very best plans scientifically for habitat - bar none - in the United States.
The boundaries of the plan were actually developed by a scientific team without any kind of political pressure. Some of the very best scientists who know the Southern California desert ecosystems were involved.