The Colorado Plateau is rich in endemic plant species, which are species that are restricted to a particular region. Of the more than 3,000 vascular plants that have been documented in the region, about 10% are endemic, or found only in the Colorado Plateau. The Plateau supports the largest concentration of endemic plants of any region in the U.S. This high level of endemism can be attributed to the geological and environmental complexity and highly variable and stressful environments of the area, particularly limited water in a warm desert habitat. Stress is an important stimulus for the evolution of specialized and narrowly distributed species. Some endemic species may have recently evolved (neoendemics), while others are relict species from previous environments (paleoendemics), which may have been significantly different in climate. Geographic isolation from other populations of the same species also contributes to genetic diversity, which can cause the evolution of an entirely new species.
As the environment of the Colorado Plateau continues to change, vegetation communities and their associated species will continue to change or possibly become extinct. Plants that are able to evolve and respond to the environmental stress will survive, and species that were once widely distributed may become endemic to the area. By protecting and preserving the Colorado Plateau, including Glen Canyon NRA, the species unique to the region may continue to survive and evolve, providing opportunities to increase our knowledge of distribution and biology. Species in danger of extinction can be protected under the Endangered Species Act of 1973, so long as their habitats are protected. Without such protection, these irreplaceable and unique genetic resources could be lost.