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The saguaro cactus (Carnegiea gigantea) is a conspicuous component of the Sonoran Desert, occurring in southern Arizona, the southeastern tip of California, and northern Sonora, Mexico. The range of saguaros overlaps with many of the most rapidly growing urban areas in Arizona. The demand for land has increasingly led to the development of prime saguaro habitat. Until recently, many developments have been accomplished by the destruction of all vegetation on housing sites and the reintroduction of vegetation after building has been completed. Public outcry over the destruction of saguaros has led to the re-evaluation of this practice and the transplant requirement in some development mitigation plans.
Evaluation of saguaro transplant as a means of saving plants from destruction is complicated by several factors. First, although transplanting saguaros is a common practice, few salvage operations have kept statistics on transplant success. Second, even under natural field conditions there is often a lag of 1–10 years between the time a plant is injured and the time of death as determined by a plant's collapse. Transplanted saguaros must therefore be monitored for 10 years and survivorship rates compared to those for non-transplanted individuals.
We are measuring the survival rate of transplanted saguaros at a golf course and housing development in Tucson, Arizona, over a 10-year period. Our study consists of 800 transplanted saguaros (treatment), 100 untransplanted saguaros located next to the golf course (Control 1), and 100 untransplanted saguaros located in an adjacent wilderness area (Control 2). Results following 2 years of study show 6% mortality in the transplanted group, 5% in the golf course control group and 0% in the wilderness control group. This study is intended to aid urban planners and natural resource managers determine appropriate mitigation policies in areas where saguaros naturally occur and where future urban development is planned.