Plants and Animals
Plants and General Life Zones of the Canyon
It is difficult to apply distinct “boundaries” to flora within the Grand Canyon; however, there aregeneral elevations that tend to promote some plant communities over others, simply based on temperature, air currents, water flows and slope degree. For instance, trees are not supported in low-desert country below 4,500 feet unless they are near permanent water; and small trees best thrive in dry, exposed terrain between elevations of 4,500 – 8,000 feet. On the Kaibab Plateau of the North Rim, dense forests and lush meadows thrive in higher elevations. Both rims support mature forests of ponderosas and allow sunlight for mountain grasses, wildflowers and oak. As one descends in elevation, trees diminish in size and desert-friendly plants that are of a hardier nature begin to thrive.
Here are the different ecological zones of the Canyon, their general elevations, and what typically grows within these areas:
|Boreal||8,000 - 9,100 feet||SPRUCE-FIR FOREST: Douglas fir, White fir, Subalpine fir, Mountain ash, Engelmann and Blue spruce.|
|Transition||7,000 - 8,000 feet||PONDEROSA PINE FOREST: Big Sagebrush, Gambel oak, Ponderosa Pine, Quaking aspen, Indian paintbrush and Lupine.|
|Upper Sonoran||4,000 - 7,500 feet||PINYON PINE – JUNIPER WOODLAND: Pinyon pine, Utah juniper, Mormon tea, Brittlebush, Apache plume and Banana yucca.|
|Lower Sonoran||River - 4,500 feet||DESERT SCRUB: Barrel cactus, Blackbrush, Honey Mesquite, Acacia, Hedgehog cactus and Opuntia cactus.|
|Riparian||Banks of Co. River||RIPARIAN WOODLANDS: Fremont, Cottonwood and Tamarisk.|
Fauna and Animals of the Grand Canyon
The Grand Canyon passes through three of North America’s four Deserts, the Great Basin Desert (Nevada and western Utah), the Sonoran Desert (south-central Arizona and northwestern New Mexico) and the Mohave Desert (found in portions of Havasu Canyon and Lake Mead). The direct sun of the southwest and the arid climate challenges wildlife to sustain their energies and minimize their water needs in order to hunt without overheating. Foraging for food is limited to hours of the day least effected by the desert sun, and most animals are active in the cooler hours of dawn and dusk or during the night (nocturnal).
A great variety of fauna may be seen in the Grand Canyon. Mammals include bats, bighorn sheep, coyotes, desert cottontails, elk, mountain lions, mule deer, raccoons, ringtails and squirrels. There is a healthy variety of birds in the Canyon that includes bald eagles, common ravens, golden eagles, great horned owls, peregrine falcons, red-tailed hawks, white-throated swifts, violet-green swallows, turkey vultures, and wild turkeys. The growth of vegetation on the riverbanks has promoted an increase in the number of birds found within the Inner Canyon. Over 60 species of birds have been identified that breed along the river and over 155 species have been observed that are non-breeding and migratory. Reptiles and invertebrates inhabit the Canyon in abundance and include chuckwallas, collared lizards, rattlesnakes, short-horned lizards, sonoran gopher snakes, black widows and scorpions. There are 17 species of snakes in the river corridor alone; however, all are rarely encountered.
Native fish species of the Grand Canyon include the Bonytail Chub, Humpback Chub, Roundtail Chub, Colorado Pikeminnow, Speckled Dace, Razorback Sucker, Flannelmouth Sucker, and Bluehead Sucker. Fish species that were introduced include Rainbow Trout, Cutthroat Trout, Brown Trout, Brook Trout, Carp, Golden Shiner, Fathead Minnow, Channel Catfish, Black Bullhead, Rio Grande Killifish, Striped Bass, Largemouth Bass, Green Sunfish, Bluegill Sunfish and Walleye.
The Grand Canyon regulates the distribution of animals, acting as a barrier as well as a corridor for dispersal and migration. In some cases, species are found to inhabit only one side of the Canyon, which is the case with the Abert squirrel that is only found on the South rim and the Kaibab squirrel that lives exclusively on the North rim. Similarly, the long-tailed pocket mouse is found on the north side of the Colorado River and the rock pocket mouse lives only on the south side, and giant water bugs, gila monsters and other reptiles are found exclusively in the lower Canyon. As a nature refuge, the Grand Canyon acts as a safe harbor for rare species such as the pink rattlesnake, a subspecies of the western rattlesnake that can only be found in the Grand Canyon.
Impact of the Glend Canyon Dam on Riparian Flora and Fauna
Glen Canyon Dam is located approximately 10 miles from Lees Ferry on the Colorado River. As part of the Upper Colorado River Storage Project, it controls flooding, stores water, provides recreational opportunities and generates hydroelectric power to the region. Construction of the Dam has created a vast recreational area covering 1.25 million acres that includes Lake Powell as its central attraction with a shoreline of 1,960 miles. Overall, the Glen Canyon Dam has had both a positive and negative impact on the development of flora and fauna species within the Inner Canyon.
Cold water from the Dam, for instance, has negatively impacted the breeding patterns of over 7 native fish species forcing them to spawn in warmer waters found at the heads of Havasu Creek and the Little Colorado River. In addition to this, the tamarisk plant, an exotic Arabian species originally used for flood bank control, has thrived to the point of taking over many Inner Canyon beaches. While young tamarisk plants are soft with flexible stalks, older plants have wood trunks, creating dense thickets that make it difficult for hikers to move through.
In a positive sense, flood control within the Inner Canyon has allowed single-celled plants and algae to thrive. This has in turn enabled fish species and aquatic invertebrates to colonize such as insects, butterflies and moths. The result is that there has been a significant growth of streamside animal communities and beach habitat that rely on perennial plants. Previous to the construction of the Glen Canyon Dam, seasonal flooding of the Colorado River regularly washed away vegetation on the river. In 1921, for instance, the Colorado River charted a record flow of 200,000 cubic feet per second, versus an average of 8,000 cubic feet per second during the Post-Dam era. In a short 24-year period, it was calculated that 4 billion tons of sediment was transported through the Inner Canyon resulting in an annual deposit of mud, sediment and sand. Glen Canyon Dam may have altered the virgin environment of the Inner Canyon, however, it has enabled the growth of flora and fauna communities that previously would not have had a chance to survive.