Scottsdale’s McDowell Sonoran Preserve What’s that tall cactus with all the arms? That’s just one of the questions sparked by the lush landscape of Scottsdale’s McDowell Sonoran Preserve. This 30,580-acre sanctuary is home to thousands of species of cacti, plants and animals. Here's a quick guide to some of the desert residents you’ll see as you explore the Preserve’s 225+ miles of hiking, biking and horseback riding trails.