At
Grand Canyon 75 species of mammals, 50 species of
reptiles and amphibians, 25 species of fish, and over
300 species of birds exist.
The
South Rim of Grand Canyon lies on the edge of a high
plateau whose gray-green forests stand out in sharp
contrast to the arid lands below the rim. From here
the cliffs drop 5000 feet/1524 m to the Colorado
River, crossing several biotic zones in the process.
It is a landscape characterized by abundant sunshine,
extremes of temperature, and long periods of drought
punctuated by torrential downpours in summer and snow
in winter. The soil is thin; bedrock lies just a few
inches below the surface. The competition for moisture
in this dry land is keen.
On
the rim at elevations above 7000 feet/2134 m,
ponderosa pine is the dominant tree in the forest.
Below 7000 feet/2134 m, pinyon pine and Utah
juniper are the dominant trees. Gambel oak is another
common member of the forest. The trees are interspersed
with drought-resistant shrubs like cliffrose, fernbush,
and serviceberry. Warm, sunny areas along the rim
may be home to desert plants like banana yucca and
claretcup cactus.
Below
the rim, it's another world. The temperature within
the inner canyon can be as much as 30 degrees F/18
degrees C higher than temperatures on the rim.
Summertime highs along the Colorado River can reach
120 degrees F/49 degrees C. Much of the inner
canyon is considered desert, excluding the areas along
the river and tributary streams which have rich riparian
(streamside) habitat. Much of the vegetation in the
inner canyon is typical of that found in deserts to
the south: cacti and drought-resistant shrubs. Riparian
plants include thickets of willow and tamarisk.
The
park is home to a wide variety of animals. Mule deer
are common throughout the park and are the mammals
most commonly seen on the rim. Desert bighorn inhabit
the remote slopes of the inner canyon but are occasionally
seen on established trails. Bobcats and coyotes range
from rim to river, and a small population of mountain
lions exists in the park. Among the smaller mammals
that inhabit Grand Canyon are ringtails (closely related
to raccoons), beavers, gophers, chipmunks, several
varieties of squirrels, rabbits and bats. Reptiles
and amphibians are represented by a wide variety of
lizards, snakes (including the unique Grand Canyon
"pink" rattlesnake), turtles, frogs, toads
and salamanders. Hundreds of species of birds make
their home in the park, along with countless insects
and arachnids (spiders and scorpions).
Grand
Canyon National Park is home to a number of threatened
and endangered species. The native Colorado River
fish have suffered as a result of the dramatic changes
in water volume, temperature and sediment load since
the completion of Glen Canyon Dam in 1963. These fish
include the Colorado squawfish, humpback chub, and
bonytail chub. Several species of endangered birds
make Grand Canyon home, including the peregrine falcon,
bald eagle, and willow flycatcher. A number of endangered
plants can also be found in the park, including. More
and more, protected lands like Grand Canyon National
Park provide a refuge for plants and animals that
are under increasing pressure elsewhere.
