Petrified Forest National Park, Navajo, Apache, Arizona, United States

The dominant plants in the park include more than 100 grass species, many native to the region. Growing among the grasses are flowering species such as evening primrose, mariposa lily, and blue flax, and shrubs such as sagebrush, saltbush, and rabbitbrush. Among the wide variety of grasses are native perennial bunchgrass, blue grama, sacaton, sideoats grama, bearded sprangletop, and bush muhly. Invasive species that crowd out slower-spreading natives include annual lovegrass and brome (cheat grass).
Trees and shrubs grow in riparian zones along the park's washes. Willows and cottonwoods are the larger plants, joined by rushes and sedges. There the invasive Eurasian tamarisk, also known as saltcedar, threatens native plants by crowding, using most of the available water, and increasing soil salinity by exuding salt through its leaves.
• Fauna
Some of the larger animals roaming the grasslands include pronghorns, black-tailed jackrabbits (hares), Gunnison's prairie dogs, coyotes, bobcats and foxes. Pronghorns, the fastest land animals in North America, are capable of 60-mile-per-hour (97 km/h) sprints. The blood vessels in the huge, thin-walled ears of the jackrabbits act as heat exchangers. These hares are known for their bursts of speed, long leaps, and zigzag routes, all of which protect them from being eaten by golden eagles and other predators. The prairie dogs live in large colonies or "towns", near which many other species find food and shelter. Coyotes dine largely on rodents but also eat fruits, reptiles, insects, small mammals, birds, and carrion.