Zion’s Natural Diversity

With an elevation change of about 5,000 feet from the highest point at Horse Ranch Mountain (8,726 feet) to the lowest point at Coal Pits Wash (3,666 feet), a myriad of habitats and species thrive in Zion National Park. Plants vary, as fir, ponderosa pine, and aspen prefer the snowy highcountry winters, while pinon, cliffrose, and mesquite flourish in the desert heat. Likewise, animal life is diverse. Tiny pinon mice, golden eagles, and mountain lions are all found in Zion National Park.

Water and Wildlife

The lack or abundance of water is the deciding factor for what grows where. On the plateau, above the canyon rim, annual precipitation tops 26 inches, so sego lilies, greenleaf manzanita, yellow-bellied marmots, fir, elk, and black bear are all found. In the desert below, over 500 times more species exist. The Virgin River’s perennial waters give life to Fremont cottonwood, singleleaf ash, and boxelder. The rare Zion snail lives only in the isolated hanging gardens that grow with maidenhair fern, scarlet monkeyflower, and golden columbine. Canyon treefrogs can be heard by sleeping campers, and great blue herons can be seen wading in the water. When the summer monsoons send flash floods roaring down canyons, it’s remarkable that anything survives.

Away from the river, Zion Canyon’s annual precipitation may total as little as 15 inches. At the lowest elevations, Mojave Desert species such as desert tortoise and honey mesquite dwell in Zion’s dry canyons. At mid-elevations, Great Basin Desert species like shadscale and big sagebrush coexist with Colorado Plateau’s bigtooth maple and Utah juniper. The biodiversity of Zion is the result of these three communities coming together in one remarkable location.

Geology’s Impact

Part of the reason for Zion’s uniqueness lies in its geology. The soil of both the Great Basin and Mojave Desert are similar over great distances, but Zion’s stacked prehistoric environments erode into many soils. The Chinle Formation’s ancient lakes and volcanic ash, for example, corrode into a soil rich in the poisonous mineral selenium. Plants like prince’s plume and milkvetch (locoweed) grow on such odd soils and increase Zion’s diversity. Individual canyons also increase isolation of some species and can lead to variation.

A Changing Environment

Zion National Park is remarkable and beautiful, but not pristine. Over 150 years of farming, grazing, and recreation have changed Zion’s environment. Exotic species like tamarisk and cheatgrass replace native willow and native grasses. The mission of the National Park Service is to provide sanctuary for and reinvigorate the remaining diversity in Zion. Although much has changed, Zion remains a magnificent place.