The Lower Sonoran life zone spans from the Colorado River up to 3,500 feet (1,100 m).
Along the Colorado River and its perennial tributaries, a riparian community exists.
Coyote willow, arrowweed, seep-willow, western honey mesquite, catclaw acacia, and exotic tamarisk (saltcedar) are the predominant species.
Hanging gardens, seeps and springs often contain rare plants such as the white-flowering western redbud, stream orchid, and Flaveria mcdougallii.
Endangered fish in the river include the humpback chub and the razorback sucker.

The three most common amphibians in these riparian communities are the canyon tree frog, red-spotted toad, and Woodhouse's Rocky Mountain toad.
Leopard frogs are very rare in the Colorado River corridor, they have undergone major declines and have not been seen in the Canyon in several years.
There are 33 crustacean species found in the Colorado River and its tributaries within Grand Canyon National Park.
Of these 33, 16 are considered true zooplankton organisms.

Only 48 bird species regularly nest along the river, while others use the river as a migration corridor or as overwintering habitat.
The bald eagle is one species that uses the river corridor as winter habitat.

River otters may have disappeared from the park in the late 20th century, and muskrats are extremely rare.
Beavers cut willows, cottonwoods, and shrubs for food, and can significantly affect the riparian vegetation.
Other rodents, such as antelope squirrels and pocket mice, are mostly omnivorous, using many different vegetation types.
Grand Canyon bats typically roost in desert uplands, but forage on the abundance of insects along the river and its tributaries.
In addition to bats, coyotes, ringtails, and spotted skunks are the most numerous riparian predators and prey on invertebrates, rodents, and reptiles.

Raccoons, weasels, bobcats, gray foxes, and mountain lions are also present, but are much more rare.
Mule deer and desert bighorn sheep are the ungulates that frequent the river corridor.
Since the removal of 500 feral burros in the early 1980s, bighorn sheep numbers have rebounded.
Mule deer are generally not permanent residents along the river, but travel down from the rim when food and water resources there become scarce.

The insect species commonly found in the river corridor and tributaries are midges, caddis flies, mayflies, stoneflies, black flies, mites, beetles, butterflies, moths, and fire ants.
Numerous species of spiders and several species of scorpions including the bark scorpion and the giant desert hairy scorpion inhabit the riparian zone.

Eleven aquatic and 26 terrestrial species of mollusks have been identified in and around Grand Canyon National Park.
Of the aquatic species, two are bivalves (clams) and nine are gastropods (snails).
Twenty-six species of terrestrial gastropods have been identified, primarily land snails and slugs.

There are approximately 41 reptile species in Grand Canyon National Park.
Ten are considered common along the river corridor and include lizards and snakes.
Lizard density tends to be highest along the stretch of land between the water's edge and the beginning of the upland desert community.
The two largest lizards in the canyon are gila monsters and chuckwallas.
Many snake species, which are not directly dependent on surface water, may be found both within the inner gorge and the Colorado River corridor.
Six rattlesnake species have been recorded in the park.

Above the river corridor a desert scrub community, composed of North American desert flora, thrives.
Typical warm desert species such as creosote bush, white bursage, brittlebush, catclaw acacia, ocotillo, mariola, western honey mesquite, four-wing saltbush, big sagebrush, blackbrush and rubber rabbitbrush grow in this community.
The mammalian fauna in the woodland scrub community consists of 50 species, mostly rodents and bats.
Three of the five Park woodrat species live in the desert scrub community.

Except for the western (desert) banded gecko, which seems to be distributed only near water along the Colorado River, all
The Lower Sonoran life zone spans from the Colorado River up to 3,500 feet (1,100 m). Along the Colorado River and its perennial tributaries, a riparian community exists. Coyote willow, arrowweed, seep-willow, western honey mesquite, catclaw acacia, and exotic tamarisk (saltcedar) are the predominant species. Hanging gardens, seeps and springs often contain rare plants such as the white-flowering western redbud, stream orchid, and Flaveria mcdougallii. Endangered fish in the river include the humpback chub and the razorback sucker.
The three most common amphibians in these riparian communities are the canyon tree frog, red-spotted toad, and Woodhouse's Rocky Mountain toad. Leopard frogs are very rare in the Colorado River corridor, they have undergone major declines and have not been seen in the Canyon in several years. There are 33 crustacean species found in the Colorado River and its tributaries within Grand Canyon National Park. Of these 33, 16 are considered true zooplankton organisms.
Only 48 bird species regularly nest along the river, while others use the river as a migration corridor or as overwintering habitat. The bald eagle is one species that uses the river corridor as winter habitat.
River otters may have disappeared from the park in the late 20th century, and muskrats are extremely rare. Beavers cut willows, cottonwoods, and shrubs for food, and can significantly affect the riparian vegetation. Other rodents, such as antelope squirrels and pocket mice, are mostly omnivorous, using many different vegetation types. Grand Canyon bats typically roost in desert uplands, but forage on the abundance of insects along the river and its tributaries. In addition to bats, coyotes, ringtails, and spotted skunks are the most numerous riparian predators and prey on invertebrates, rodents, and reptiles.
Raccoons, weasels, bobcats, gray foxes, and mountain lions are also present, but are much more rare. Mule deer and desert bighorn sheep are the ungulates that frequent the river corridor. Since the removal of 500 feral burros in the early 1980s, bighorn sheep numbers have rebounded. Mule deer are generally not permanent residents along the river, but travel down from the rim when food and water resources there become scarce.
The insect species commonly found in the river corridor and tributaries are midges, caddis flies, mayflies, stoneflies, black flies, mites, beetles, butterflies, moths, and fire ants. Numerous species of spiders and several species of scorpions including the bark scorpion and the giant desert hairy scorpion inhabit the riparian zone.
Eleven aquatic and 26 terrestrial species of mollusks have been identified in and around Grand Canyon National Park. Of the aquatic species, two are bivalves (clams) and nine are gastropods (snails). Twenty-six species of terrestrial gastropods have been identified, primarily land snails and slugs.
There are approximately 41 reptile species in Grand Canyon National Park. Ten are considered common along the river corridor and include lizards and snakes. Lizard density tends to be highest along the stretch of land between the water's edge and the beginning of the upland desert community. The two largest lizards in the canyon are gila monsters and chuckwallas. Many snake species, which are not directly dependent on surface water, may be found both within the inner gorge and the Colorado River corridor. Six rattlesnake species have been recorded in the park.
Above the river corridor a desert scrub community, composed of North American desert flora, thrives. Typical warm desert species such as creosote bush, white bursage, brittlebush, catclaw acacia, ocotillo, mariola, western honey mesquite, four-wing saltbush, big sagebrush, blackbrush and rubber rabbitbrush grow in this community. The mammalian fauna in the woodland scrub community consists of 50 species, mostly rodents and bats. Three of the five Park woodrat species live in the desert scrub community.
Except for the western (desert) banded gecko, which seems to be distributed only near water along the Colorado River, all 
Grand Canyon