The ancient people who lived in the Preserve left behind petroglyphs, some easily seen from the trail.
Conservancy Pastfinders study the history of the area.
It’s said that people won’t save what they don’t love, and they won’t love what they don’t know. We want people to get to know the Preserve, and the plants, animals, geology, and human history that makes it distinctive and worth protecting. If you are interested in learning more about the desert, enjoy the information presented here, or come with us on a hike, or to a presentation offered by one of our volunteer experts.
The McDowell Sonoran Preserve is in the Arizona Upland subdivision of the Sonoran Desert, the highest and coldest part of the desert. Trees are common on rocky slopes and in washes, with saguaros also present on the slopes. It is subject to occasional hard winter frosts which restrict some desert plants from growing here, but the McDowell Mountains provide many microhabitats which help increase species richness.
Desert plants use one of three basic strategies to adapt to the arid climate. Succulence – the ability to store water in fleshy leaves, stems or roots in compounds from which it is not easily lost – is characteristic of all cacti, agaves, aloes, and others. Drought tolerance – the ability to withstand dessication for months or even years without rain – is characteristic of many desert shrubs such as creosote bush and brittlebush. Drought evasion – avoiding unfavorable conditions by growing and blooming only when specific environmental conditions are met – is characteristic of many desert annual wildflowers.
For a list of plants known to occur in the McDowell Sonoran Preserve, click here.
The McDowell Sonoran Preserve consists of mountains rising to 4,000’, rolling uplands, and natural wildlife corridors linking the Preserve with the Tonto National Forest and the McDowell Mountain Regional Park. Together they form a sustainable desert habitat for wildlife of all kinds. Wildlife-viewing and birding are passive recreational activities popular with visitors to the McDowell Sonoran Preserve.
Much of the animal life of the desert is nocturnal, one way that animals adapt to the heat and aridity, so viewing is often best in the morning or evening.
The McDowell Mountains and the surrounding smaller peaks and desert are the result of billions of years of geological processes.
The visible landscape of the Preserve is the product of relatively recent geological events, but the rocks that make up the landscape are much, much older than the events that created what we see today. The basic rock underlying the Preserve is ancient granite and metamorphic rock formed between 1.4 and 1.7 billion years ago. This rock was mostly underwater for more than a billion years, during which time it became covered with a thick layer of sediment that became sedimentary rock. The geological processes that created the Rocky Mountains about 65 – 75 million years ago (MYA) also lifted central Arizona above sea level, which caused this thick layer of sedimentary rocks on top of the granite and metamorphic rock to begin to erode away.
The major geological process that shaped the local landscape was the formation of the basins and ranges. Between 8 and 15 MYA, volcanic activity beneath the crust stretched the surface of central and southwestern Arizona. The surface began to crack in many places, forming parallel north – south cracks. Earthquakes and continuing volcanism caused some of the regions between cracks to slide downward by as much as 4 miles, while other areas did not. The lower areas are now called basins and the higher areas are called ranges. The McDowell Mountains, the Phoenix Mountains, and the Sierra Estrellas are parallel, roughly north-south ranges created during this period. The valleys in between, including metropolitan Phoenix, are examples of basins. The basins have mostly filled with sediment eroding off of the ranges in the millions of years since they were formed. In the McDowells, almost all of the sedimentary rocks have eroded away, leaving mostly granite and metamorphic rock.
The first people/culture to wander the mountains of the McDowell Sonoran Preserve are the Archaic People. From 7000 BCE – 400 CE, they were wandering bands of hunters and gatherers who lived off of the fruits, seeds, and animals they could obtain in the mountains and surrounding foothills. They did not depend on agriculture for their subsistence.
The next people/culture to inhabit these mountains were the Hohokam. From 100 – 1450 CE, they created extensive towns/settlements in the Valley where Phoenix, Mesa, Tempe and Scottsdale exist today. They settled mostly near rivers and developed extensive canal systems in order to raise crops like corn, beans, squash and cotton. But they also needed fruits, seeds and meat, so they would hunt and gather here much like the Archaic people.
The Hohokam culture began to fade around 1400 to 1450 CE, and was replaced by the Yavapai and Apache cultures. The Yavapai came here from around Sedona or perhaps somewhat west of there. The Apache came from the northwest – where the states of Washington and Oregon exist today. Like the Archaic people, they were primarily hunters and gatherers.
Toward the end of the Civil War the United States government began sending large numbers of troops to the western states like Arizona in order to suppress the Native American nations and open the land for development of mining, ranching, farming, etc.
Ft. McDowell was built in 1865, immediately east of the McDowell Mountains. The fort, and later the mountains, were named for a Civil War general – Irvin McDowell. Troops from the fort were used to suppress the local Yavapai and Apache bands.
As the local Yavapai and Apache bands were suppressed and confined to reservations, the McDowell Mountains and surrounding valleys became safe for cattle ranching, farming and mining. In 1888 a retired military chaplain, Winfield Scott, moved here and founded the settlement of Scottsdale.
Between 1939 and 1945 an event occurred that would have a profound impact on our area’s population growth. It was World War Two. During the 1940s there were several flight training facilities built in and near Scottsdale. In addition, several aircraft related industries and defense contractors relocated their production facilities to the Phoenix/Scottsdale/Tempe/Mesa area. After the war, many young men who had trained here and learned to love the Sonoran Desert winters decided to return and live here permanently. The population grew from 2,000 in 1950 to 225,000 in 2000.