Endangered Species and the Arizona-Sonora Desert Museum

Article excerpt

The Arizona-Sonora Desert Museum, a nonprofit research and education institution located in the city of Tucson, is a combination zoological park, botanical garden, nature center, and museum. Our multiple functions are reflected in our memberships in the American Zoo Association (AZA), American Association of Botanical Gardens and Arboreta, American Association of Museums, and Center for Plant Conservation, among others. Our primary mission is to understand and interpret the natural history and ecology of the Sonoran Desert and its surrounding habitats, and to promote conservation in the region.

The Sonoran Desert covers about 100,000 square miles (260,000 square kilometers) in the United States and Mexico. In contrast to the other three North American deserts, the Sonoran is tropical in origin and most of its area is frost-free. Half of its flora and a similar proportion of the fauna are descended from tropical ancestors. This fact is visually evident in two plant life forms that are characteristic of both the Sonoran Desert and dry tropical forests: legume trees and columnar cacti. The other three North American deserts have few trees and no columnar cacti.

Numerous biological communities occur adjacent to and within the Sonoran Desert proper. Representatives of all of the biomes can be found within this region, from alpine tundra near Flagstaff, Arizona, to tropical forests in southern Sonora, Mexico.

The wide variety of habitats and the biseasonal rainfall pattern in the Sonoran Desert support great biological diversity. Its flora contains about 2,000 species of vascular plants, and the whole region interpreted by the Desert Museum has at least 5,000. The desert proper supports approximately 600 species of vertebrates. The invertebrates have not been enumerated, but there are estimates for some taxa. Arizona alone boasts 40 species each of scorpions and velvet ants, and 250 butterflies; the Sonoran Desert has 40 species of termites. The area around Tucson has 1,000 species of native bees, and an equal number of moth species occurs in a single canyon in the Huachuca Mountains of southern Arizona.

Most of our exhibits at the Arizona-Sonora Desert Museum are outdoors and integrate native, live animals and plants in natural settings. Our interpretive focus is as much on ecological processes as it is on individual species. For example, our Pollination Gardens interpret the interaction of animals and plants and the reciprocal benefits of pollination ecology rather than simply talking about, say, hummingbirds or flowering ocotillos.

We mainly promote in situ conservation (that is, conservation of nature in place as opposed to in botanical gardens or zoos), and we focus on the protection of natural communities more than on preservation of individual species. For example, research on the ecology and population dynamics of desert ironwood trees (Olneya tesota) revealed just how important this plant is to the ecological health of the Sonoran Desert and its wildlife. These findings attracted the attention of the Department of the Interior and provided the scientific underpinnings for the creation of the Ironwood Forest National Monument in 2000. The ironwood studies and other research results have also been used by Pima County in developing its Sonoran Desert Conservation Plan (see the following article).

The Desert Museum also maintains ex situ or museum-based populations of several endangered species. The animals bred as part of our participation in AZA's Species Survival Plan program include the Mexican gray wolf (Canis lupus baileyi), thick-billed parrot (Rhynchopsitta pachyrhyncha), and ocelot (Leopardus pardalis). Our Botany Department maintains populations of several endangered plants, including the Nichol's Turk's head cactus (Echinocactus horizonthalonius var. nicholii), Pima pineapple cactus (Coryphantha scheeri var. robustispina), and Kearney blue-star (Amsonia kearneyana). …