Saguaro National Park in the context of Rincon Mountains

In conservation biology, a flagship species is a species chosen to raise support for biodiversity conservation in a given place or social context. Definitions have varied, but they have tended to focus on the strategic goals and the socio-economic nature of the concept, to support the marketing of a conservation effort. The species need to be popular, to work as symbols or icons, and to stimulate people to provide money or support.

Species selected since the idea was developed in 1980s include widely recognised and charismatic species like the black rhinoceros, the Bengal tiger, and the Asian elephant. Some species such as the Chesapeake blue crab and the Pemba flying fox, the former of which is locally significant to Northern America, have suited a cultural and social context. Although animal species that can be described as "charismatic megafauna" are frequently the flagship species for a protected ecosystem, large, dominant plant species sometimes serve this role as well, for example, several United States national parks, including Redwood National and State Parks, Joshua Tree National Park, and Saguaro National Park, are named for the flagship plant species for those protected areas. Butterfly species, such as the monarch butterfly, have also served as flagship species in some contexts.

The saguaro (/səˈ(ɡ)wɑːroʊ/ sə-(G)WAR-oh, Spanish: [saˈɣwaɾo]; Carnegiea gigantea) is a tree-like cactus species in the monotypic genus Carnegiea that can grow to be over 12 meters (40 feet) tall. It is native to the Sonoran Desert in Arizona, the Mexican state of Sonora, and the Whipple Mountains and Imperial County areas of California. Saguaro typically grow at elevations ranging from sea level to 4,500', although they may be found at up to 5,000'. The saguaro blossom is the state wildflower of Arizona. Its scientific name is given in honor of Andrew Carnegie. In 1933, Saguaro National Park, near Tucson, Arizona, was designated to help protect this species and its habitat.

Saguaros have a relatively long lifespan, often exceeding 150 years. They may grow their first side arm around 75–100 years of age, but some never grow any arms. Arms are developed to increase the plant's reproductive capacity, as more apices lead to more flowers and fruit. A saguaro can absorb and store considerable amounts of rainwater, visibly expanding in the process, while slowly using the stored water as needed. This characteristic enables the saguaro to survive during periods of drought. It is a keystone species, and provides food and habitat to a large number of species.

Vail is a census-designated place (CDP) in Pima County, Arizona, United States. It is 24 miles (39 km) southeast of Tucson. The population was 10,208 at the 2010 census, up from 2484 in the 2000 census. The area is known for the nearby Colossal Cave, a large cave system, and the Rincon Mountains District of Saguaro National Park, a top tourism spot within Arizona.

Vail was originally a siding and water stop on the Southern Pacific Railroad. It was located on the last section of flat land before the train tracks followed the old wagon road into the Cienega Creek bed. Vail was named after pioneer ranchers Edward and Walter Vail, who established ranches in the area in the late 19th century. Vail deeded a right of way across his ranch to the railroad. Vail owned the Vail Ranch, his brother Walter Vail owned the nearby Empire Ranch, now part of the Las Cienegas National Conservation Area. Attempts to incorporate the town were defeated in 2013 and 2023.

Homer LeRoy Shantz (1876–1958) was an American botanist and former president of the University of Arizona.

Shantz was born in Kent County, Michigan on January 24, 1876. He was raised in Colorado Springs, Colorado, where his family moved while he was still young. Shantz graduated from Colorado College in 1901 with a bachelor's degree in botany. He received his doctoral degree in botany from the University of Nebraska in 1905. Following graduation until 1908 he taught botany at the state universities in Missouri and Louisiana before accepting a position with the United States Department of Agriculture. He traveled widely, with an emphasis on the American West and Africa, and made documentary photographs wherever he went. Among Shantz's research interests was the photographic documentation of vegetation change. He served as the President of the University of Arizona from 1928 to 1936, where he focused his attention on Arizona and the Sonoran Desert. During this period, he worked with John E. Harrison Jr. in the acquisition of land for the creation of what is now called the Saguaro National Park In 1936, he resigned after disagreements with the legislature and the Board of Regents.