In 1990, with the combined population of the nearby communities of Scottsdale, Fountain Hills, Rio Verde and Carefree approaching 150,000, housing and commercial developments were beginning to encroach upon the McDowell Mountains.
[3] On November 17, 1990, thirteen concerned preservationists and outdoor enthusiasts met at Scottsdale's Mustang Library to discuss preservation of the McDowell Mountains and adjacent Sonoran Desert lands.
The MSLT board quickly realized that a reliance on private donations would not provide effective funding for the purchase and preservation of sufficiently large parcels of land.
In 1992, they approached the Scottsdale city council with a request to develop a preservation plan[6] for the McDowell Mountains and surrounding Sonoran Desert lands.
Public support came the following year when 64% of Scottsdale's voters approved a 0.2% sales tax to fund land acquisition.
The stewardship concept as a partnership with city staff was purpose-built for the Scottsdale environment and remains a unique model among land trusts in the United States.
The Preserve connects in the north with the three-million-acre Tonto National Forest and in the southeast with the 21,000 acre McDowell Mountain Regional Park, providing an uninterrupted wildlife corridor.
The southern portion, consisting mainly of the McDowell Mountain range, is largely composed of erosion-resistant metamorphic rocks formed about 1.7 billion years ago.
An unusual feature of the northern Preserve is the appearance of geologically young (15 to 25 million years old) volcanic deposits from the nearby Superstition Mountains.
[9] The McDowell Sonoran Preserve currently offers approximately 120 miles of non-motorized, multi-use trails (hike/bike/horse) accessed from multiple trailheads.
These services and activities include a comprehensive volunteer stewardship program (including patrol, maintenance, trailhead hosting, and education); facilitating scientific research; website and printing resources; and advertising, promotion, special events, and membership activities for the sole purpose of promoting the use, protection, and enhancement of the Preserve.
Citizen Science: Protecting the Preserve is an interdisciplinary challenge, balancing the threats with the opportunities that coexist at the boundaries separating the urban from the desert environments.
Citizen-scientist stewards support monitoring and assessment of the natural and historic resources in the Preserve, and share this information through educational talks and programs.
They assess trail conditions for both safety and sustainability and provide reports that help Scottsdale and Conservancy staff to properly manage the Preserve.
Research results are used for long-term resource management, education, and to contribute to the broader scientific knowledge of natural areas.
[16] An anonymous-donor contribution in 2009 and a three-year grant from the Nina Mason Pulliam Charitable Trust[17] in 2010 were used to formally establish MSFI and hire a staff leader.
The Citizen-Science program offers specialized training for volunteers interested in participating in MSFI research projects with the Principal Investigators.
Citizen-Science program volunteers do field work, data entry, basic analysis, mapping, and other tasks under staff or scientific supervision.
MSFI has published reports summarizing its work-to-date developing baseline surveys of Preserve flora, fauna, and geology.
[10][full citation needed] Current projects focus on various aspects of human impact, including the effect of trail traffic on physical trail characteristics and nearby vegetation, the impact of development along the wildland–urban interface, and monitoring restoration sites to assess alternative approaches.