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Pima County, Arizona, occupies six million acres of the Sonoran Desert; one of the largest stretches of protected arid ecosystems in the world. This unique and delicate ecosystem supports more than 2,500 pollinators, including invertebrates, birds, bats, and bees. The region also supports thousands of plant species in about 80 plant communities, such as ironwood- paloverde woodlands, saguaro cactusmesquite scrublands, cottonwood and willow riparian forests, and California fan palm oases.⁵ Pima County is also home to diverse cultures and interests, including the Tohono O’odham Native American Nation and an eclectic mix of urban and ranch communities that are growing at the rate of 20,000 residents per year. Residential growth in Pima County consumes seven to 10 square miles of the Sonoran Desert each year. This combination of unbridled development and sensitive environment set Pima County on a course for disaster.

In 1997, biologists found 12 Cactus ferruginous pygmy owls (Glaucidium brasilianum cactorum) in Pima County and soon thereafter, the owl was added to the endangered species list. Faced with a listing that would greatly affect development, Pima County could no longer ignore its growth problems. The county used the listing as an opportunity to establish a regional planning tool — the Sonoran Desert Conservation Plan (SDCP). The purpose of the current plan is “to ensure the long-term survival of plants, animals and biological communities that are indigenous to this county.” The SDCP contains six areas of focus: Habitat, Corridors, Cultural, Mountain Parks, Ranch Lands, and Riparian. The Pima County Board of Supervisors is leading the SDCP effort in coordination with 12 major government land managers and a 74-person public steering committee that includes conservationists, developers, neighborhood groups, ranchers, and private landowners.

In developing the SDCP, Pima County used the concept of “bio-planning,” or natural resource assessment and planning, as a necessary first step in determining urban form. “We broadened the vocabulary of the growth debate to include biological and scientific concepts, and reframed the elements of regional planning to encompass the relation that the land has to natural and cultural resources,” said County Administrator Chuck Huckelberry. “Our method assumes that urbanizing areas are endowed with certain natural, cultural and historical resources that should receive protection.

Based on the amount of acreage needed to stabilize and recover endangered, threatened and imperiled species, the plan outlines a conceptual biological reserve, which is combined with historic and cultural reserves. Areas identified as unique and ecologically or culturally sensitive are designated Environmentally Sensitive Lands (ESL).

In response to community concerns about potential conflicts between preserving ESLs and future roadbuilding, Pima County formed a panel of experts from multiple disciplines (roadway engineers, wildlife biologists, cultural resources experts, and a landscape architect) to develop guidelines that allow planners and designers to better account for biological, cultural and historic resources in the roadway corridor. Transportation projects occurring within designated areas are defined as Environmentally Sensitive Roadways (ESR), and are to be designed and constructed to minimize disturbances to natural resources.*

* As of early 2003, the SDCP and Key deer HCP had not been finalized, and stakeholders had serious concerns about whether the final plans would have adequate habitat protections. Nevertheless, the processes are instructive for other state DOTs, because they included a regional conservation plan, extensive scientific studies and models, community involvement, and an important role for the state DOT.

Endnotes

5. Piecing Together Wild Lands — The Sonoran Desert, National Geographic Magazine. Jennifer Fox. June, 2001