The Grand Canyon holds a diverse amount of habitat, nearly every habitat of the Southwestern United State save alpine tundra. Montane forests cover the canyon rims and the Mohave Desert habitat can be found in the western reaches of the Grand Canyon. Why is such a diverse collection of habitats here? How have these habitats changed over time? How have humans impacted these habitats? Select a circle below to learn more the natural setting of the Grand Canyon.
The Grand Canyon and its collection of side canyons cut through over a mile of rock, from the heights of 9,200 feet above sea-level on the North Rim down to 1,200 feet above sea level by the time the Colorado River reaches Lake Mead. With such a range in elevation and slope aspect, a multitude of habitats in which wildlife species can thrive have been established. The Mojave Desert influences the western sections of the canyon, Sonoran Desert vegetation covers the eastern sections, and ponderosa and pinyon pine forests grow on both rims. Natural seeps and springs percolating out of the canyon walls are home to 11% of all the plant species found in the Grand Canyon. The Canyon itself can act as a connection between the east and the west by providing corridors of appropriate habitat along its length.The canyon can also be a genetic barrier to some species, like tasseled eared squirrels.
The aspect, or direction a slope faces, also plays a major role in adding diversity to the Grand Canyon. North-facing slopes receive about one-third the normal amount of sunlight, so plants growing there are similar to plants found at higher elevations, or in more northern latitudes. The south-facing slopes receive the full amount of sunlight and are covered in vegetation typical of the Sonoran Desert.
The upper Sonoran Zone includes most of the inner canyon and South Rim at elevations from 3,500 to 7,000 feet. This zone is generally dominated by blackbrush, sagebrush scrub, and pinyon-juniper woodlands.
The dominant plant of the Mojave Desert Scrub community is the Four-winged Saltbush, Creosote bush and important associated plants include Utah agave, Narrowleaf mesquite, Ratany, Catclaw, and various cacti species. Usually dominant at elevations of 3,500 to 4,000 feet.
The South Rim is generally considered in the Upper Sonoran Life Zone and includes species such as gray fox, mule deer, bighorn sheep, rock squirrels, pinyon pine and Utah juniper.
The North Rim lies in the Boreal Zone. This zone includes the Kaibab Plateau at an elevation of over 8,250 to 9,000 feet. Mountain lions, Kaibab squirrels, northern goshawks, ponderosa pine and blue spruce are all species found here.
Seeps and springs emerging from the rims of Grand Canyon National Park are important to the region’s natural heritage for several reasons: they provide critical water and food resources to wildlife and recreational hikers; they are important point sources of biodiversity and bioproductivity in otherwise low productivity desert landscapes; and they are the focus of human activities, regional history, and land and wildlife management.
Tasseled eared squirrels possess tufts or ‘tassels” of hair extending beyond the tips of their ears. The Abert squirrel inhabits the South Rim and is peppered gray with white underparts, a narrow lateral stripe separates these colors. There is a dark chestnut or russet stripe present on the back.
The Kaibab squirrel inhabits the North Rim of the park and is found only on the Kaibab Plateau in northern Arizona. This squirrel has a black belly and white tail. As this is a unique species, it is afforded the special designation of a National Natural Landmark.
"It is the role of this wildlife research expedition, and other research endeavors, to determine just how wildlife is distributed throughout the Grand Canyon, how the canyon affects the distribution patterns, and how management actions can help ensure the preservation and protection of the life in Grand Canyon National Park."
-- Elaine Leslie, Wildlife Biologist at Grand Canyon National Park, AZ
The Grand Canyon exposes 1.7 billion years of geologic history, but that is not the only history stored here. Over 50,000 years worth of biological history is preserved throughout the Grand Canyon. This biological history records the plants and animals that have lived here, how they have changed over time, and how climate has also changed over time. Where are these storehouses of biological history to be found? They are tucked away in the hidden recesses of caves and crevices within the canyon's walls.
In these caves and crevices are the collections of packrats. Also known as woodrats and trade rats, these opportunistic small mammals collect objects to build their protective homes. Packrats find an object, such as a piece of cactus, and scurry back to their home with it in their mouth. If they find something better along the way, they drop their current treasure and trade it for the new object. Many a miner or camper in the past has awakened to find a cone or stick in place of a spoon or watch.
Packrats collect any kind of object near their nest. This includes plant matter, bones, vegetation, and other available material. Packrats build a protective abode known as a midden. This midden is a fortress of tangled vegetation, bones, sticks and other items that are held together by organic glue, the urine of the packrat. This urine hardens over time and because of its glossy, hard yellow appearance, is called amberat. Packrats also mark their area at urine posts away from the midden. In the midden are a nest, living area and food storage.
Generations of packrats can live in the same area, building middens of tremendous proportions. Some are 5-feet tall and 10-feet wide. Middens have persisted for thousands of years, becoming paleoenvironmental warehouses. Stored here are the clues to the past. The vegetation tells us of trees and plants in the past that are no longer there. The split-twig figurines tell us of past cultures. Collected dung and bone show us that ground sloths and ancient condors once were a part of Grand Canyon wildlife.
Analysis of the amberat can still tell us the physiology of the packrats themselves. Radiocarbon dating has assisted us in dating middens older than 35,000 years. There are older middens to be found, but flooding of the Grand Canyon obliterated all middens older than 150,000 years ago as the water dissolved the amberat and the middens broke apart and floated away. The floods were caused when volcanic eruptions dammed the Colorado River creating a temporary lake in the canyon. When the lava dam finally wore away, the river continued its steady downward erosion
By studying the ancient middens, paleoecologists have found that a cooler, wetter climate dominated the area from at least 50,000 years ago to 12,000 years ago. A drying trend resulted in dry-adapted plants replacing the limber pine and spruce of the ancient south rim. Pinyon pine and Utah juniper dominate the rim with ponderosa pine and Gambel oak joining them in areas with more soil and moisture. About 9-10,000 years ago, this climate change assisted in accelerating the disappearance of the large North American Mammals. The lightning storm pattern of monsoons arrived and with it the fire-adapted ponderosa pine forests of the southwest.
It is important to know how climate has changed over time, and how plants and animals responded to those changes. With knowledge of past climate changes, understanding of how future climate changes will impact the plants and animals now there can be achieved.
Middens in Grand Canyon still store the Grand Canyon's past. Camels (Camelops cf. hesternus), mountain goats (Oreamnos harrigntoni), shrub-ox (Euceratherium collinum), huge condors (Gymnogyps californicus) and the Shasta ground sloth (Nothrotheriops shastensis), all have come alive again in the packrat middens of Grand Canyon. Its exciting to think there are still more discoveries to be found.
The first explorers of the Grand Canyon region, in what is now known as Grand Canyon National Park, documented the existence of material remains belonging to prehistoric or “Moqui” Indians (Powell 1875). Later, explorers and archaeologists began to document the existence of prehistoric and historic remains, laying the groundwork for understanding human occupation in this region of the American Southwest.
The earliest known period of occupation, the Paleoindian period, began at approximately 11,500 Before Present (B.P.) and lasted approximately 3,000 years to the end of the last ice age. During this occupation, small, mobile bands of people hunted megafauna such as mountain goats, ground sloth, and bison; and gathered wild plants. Paleoindian sites are extremely rare in the Southwest; one known site has been found within the Grand Canyon.
Around 9,000 years B.P. environmental changes led to the expansion of differing environmental zones across the Southwest. During this environmental expansion, Paleoindians adapted to new environments and developed new subsistence strategies. The descendants of the Paleoindians, known as the Archaic, hunted smaller game and moved seasonally across the landscape to procure seasonal resources across vast territories. Tool kits included atlatls for dart throwing and chipped stone tools and groundstone tools such as metates and manos for plant processing. Archaic sites generally consist of temporary camps, rock art panels, caves, rock shelters, hearths or fire pits, grinding and processing tools, projectile points, flake debitage, animal and plant remains. Archaic sites have been identified throughout Grand Canyon (Fairley et al. 1994).
Experimentation with horticultural subsistence began in the Southwest around 3500 B.P. with the appearance of maize agriculture. Horticultural subsistence strategies still relied heavily on hunting and gathering local resources, though maize, beans, and squash were planted in locations where seasonal flooding allowed for the germination and growth of cultivated plants. With the adoption of a more sedentary lifestyle, storage cists and granaries were used to store surplus supplies and pottery appeared by A.D. 500. The gradual shift to village life is referred to as the Formative Period, lasting from A.D. 500 to 1540 (Neal et al. 1999).
During the Formative Period, the semi-sedentary occupants of Grand Canyon began
producing baskets, sandals, and storage features
such as slab-lined cists and granaries. This tradition first appears in the Southwest around A.D. 1. The period, often viewed as a transition to agriculture, marks the beginning of horticultural subsistence strategies. Initially, dwellings appeared as shelters in overhangs and caves. By A.D. 500, circular pithouses appear in small aggregates, suggesting the beginning of village life. Pottery appears at this time, often graywares with black painted designs. In eastern Grand Canyon, these occupations have been associated with Cohonina peoples (Schwartz 1969).
The appearance of ceramic vessels, both jars and bowls, seems to be associated with an increase in sedentary lifeways and the development of habitation structures. These structures began with semi-subterranean pithouses and shifted to above ground masonry room blocks or pueblos. The bow and arrow replaced the atlatl, and the geographic region of resource procurement expanded.
A more stable subsistence strategy of combined agriculture and hunting and
gathering allowed for the continued aggregation of
individuals into small villages or hamlets. Ceramic technology and design styles became more elaborate and new technologies developed, including the use of cotton for textiles. Surface storage rooms developed into above ground habitation structures and later, contiguous pueblos in some locales. By A.D. 900 along the river corridor, Puebloan peoples were cultivating maize, evidenced by the presence of corn pollen on living floors (Schwartz 1969). Both Tusayan Gray Ware and Tusayan White Ware ceramics increased in eastern Grand Canyon, signaling the expansion of the Kayenta Branch from the southeast.
During the later portion of the 10th century, masonry surface pueblos and semi-subterranean kivas appeared. Population growth was gradual, with the addition of single rooms to existing structures that resulted in linear pueblos of two to seven contiguous rooms. Ceramics continued to be dominated by Kayenta wares, with a gradual increase in ceramics from their northern neighbors, the Virgin Branch.
While ceramic styles remained relatively stable, after A. D. 1100 an abrupt change in architecture occurred in eastern Grand Canyon. Habitation structures became more interspersed with storage rooms and bins, fire pits, and increased use of outdoor activity areas (Schwartz 1969). Pottery distributions continued to increase in Virgin Branch styles. Habitation appears to have moved to higher terraces, perhaps to fully exploit regions adjacent to water sources for increased fertile agricultural productivity. According to Schwartz (1969), it appears that rather than population influxes from different indigenous groups, trade connections with the north were more fully developed in conjunction with localized ceramic traditions.
It is believed that by A.D. 1300, semi-nomadic, non-puebloan peoples also occupied the river corridor of Grand Canyon. These Pai and Paiute hunter-gatherers had a stable subsistence economy based on combined agriculture and hunting and gathering, supplemented by trade. Dispersed settlements included wickiup rings, rock shelters, extensive roasting complexes that included ceramics and abundant flake stone tools and debitage. It is also believed that these hunter-gatherers made use of perishables such as baskets, mats, sandals, and twine. These ancestors of the present day Hualapai and Havasupai continued to seasonally utilized both the rim and river corridor until interdiction by the U. S. Government.
In addition to indigenous populations, Europeans also traversed the Grand Canyon. The historic period includes visitation by Spanish Missionaries, mining and tourism entrepreneurs, and more recently, hydroelectric power exploration and production.
The prehistory of the river corridor in Grand Canyon closely follows the sequences of regional occupation and abandonment generally agreed upon by southwestern archaeologists. Localized variation in habitation, construction, and ceramic technologies are to be expected. No doubt the inhabitants of Grand Canyon were influenced by the same climatic changes that occurred across the entire southwest. Archaeologists also assume that population expansion along the river corridor itself was a direct result of population growth along the rims of the Grand Canyon. Because there are only a limited number of entrance and exit points into Grand Canyon, a majority of the sites recorded at permanent water sources and along access routes consist of multiple occupations through time.
Major John Wesley Powell led the first river trip down the Colorado River through the entire length of the Grand Canyon. His crew of himself and nine others survived over three months of rapids and starvation, though one member left after one month and three others left two days before the end was reached.
The first expedition proved to Powell that the Colorado River could be navigated.
He also proved his theory of the river preceding the canyon, then down-cutting
the canyon into the plateau as it rose up. He spent a lot of time conducting
research on the trip, but it was on the second expedition that he mapped the
river, documented the expedition with photographs, and published scientific
reports. He spent the time between expeditions on the lecture circuit to raise
money for the second trip.
Humans have changed the landscape of the Grand Canyon. They have forced some native species out of the area, introduced exotic species, and built dams that have altered the flow of the Colorado River.
Many species are no longer present in the Grand Canyon as a direct result of humans. Jaguars, grizzly bears, wolves, and river otters are a few of the examples of such species that no longer exist within the Grand Canyon because of direct impacts from humans.
People can also harm other species, pushing them to the edge of survival in the Grand Canyon. Impacts being researched are recreational impacts of floaters and hikers sharing the same habitat with wildlife. Some evidence suggests that bighorn, elk, and deer will ingest food wrappers, tent plastics and other human-related items. The ingestion of these materials can cause serious impacts to the digestive system of these animals.
Invasive species brought into the area by humans have been another way in which the Grand Canyon has been changed. Brown and rainbow trout eat native fish and amphibian species. The rainbow and brown trout population are now out-competing natives such as the endangered humpback chub.
The Park’s Exotic Plant Management and Restoration Program minimizes:
Explore the Invasive Species knowledge center to learn more about this topic.
One of the most dramatic ways humans have impacted the Grand Canyon is with the construction of dams. Glen Canyon Dam sits fifteen and a half miles north of Lees Ferry. Besides being a large barrier to species migrating along the river corridor, the dam traps all sediment out of the river water, and lowers the water temperatures flowing through the Grand Canyon since the water is released from the bottom of Lake Powell. Additionally, the dam has eliminated annual flooding events, so the scouring of beaches no longer occurs.
To learn more about the effects of Glen Canyon Dam, and the research being conducted on those effects, visit these web-sites:
Glen Canyon Adaptive Management Program
Grand Canyon Monitoring and Research Center