Virgin River - Ecology

Ecology

Despite flowing through an arid region, the Virgin River is home to a surprisingly diverse array of plants and animals. Southwestern Utah is located at the intersection of three physiographic regions: the Colorado Plateau, the Great Basin, and the Mojave Desert. The exceptional landscapes and habitats of this region harbor unique plant and animal communities and species found nowhere else in the world. Without the water of the Virgin River system, these species could not exist. The Virgin River directly supports hundreds of wildlife species including, woundfin, Virgin River chub, Virgin spinedace, flannelmouth sucker, desert sucker, speckled dace, and Southwestern Willow Flycatcher. Many of these species are endangered or are considered sensitive species within the State of Utah. The Virgin River Program was established to balance increasing human demand and maintain this unique system.

Woundfin (Plagopterus argentissimus) Federally listed endangered species Size: 4″ (10.2 cm) One of the most rare species on earth, the endangered woundfin is found only in a small section of the Virgin River. Woundfin have large fins and scale-less, streamlined bodies that help them survive in swift, silty conditions. Although small, it is shark-like in both appearance and action as it feeds on small insects in shallow areas along the river. Woundfin live only one to two years and their survival depends upon sufficient flow within the river, especially during hot summer months.

Virgin River chub (Gila seminuda) Federally listed endangered species Size: 18 ” (46.4 cm) Rare and beautiful, this fish is the top native predator in the Virgin River. Chub are a fast streamlined fish with a sloped forehead, humped back, and thin rounded tail. The Virgin River chub feeds on small fish, insects, and plant matter. Chub prefer deep pools and runs with boulders and debris for cover. Virgin River chub were once an important food source for Native Americans and early pioneers. Listed as an endangered species, the Virgin River chub is found from Pah Tempe Hot Springs down to Halfway Wash, Nevada.

Desert sucker (Catostomus clarkii) State of Utah wildlife species of concern Size: 18″ (46.4 cm) The desert sucker gets its name from the way it feeds on aquatic vegetation and insects. It uses its thick cartilaginous lips to scrape and suck food from rocks and boulders along the bottom of the river. Desert Suckers are very colorful during the spring spawning season, developing bright orange and black ‘racing stripes’ along their sides. Desert suckers are considered a sensitive species in Utah, where they are only found in the Virgin River and its tributaries.

Speckled dace (Rhinichthys osculus) Size: 4 ” (10.2 cm) One of the most widespread species in western North America, the speckled dace is found in large numbers throughout the Virgin River and its tributaries. Speckled dace prefer rocky areas but are comfortable living in all habitats and stream sizes. Speckled dace exhibit a kaleidoscope of shapes and colors across their range. Males display bright red “lipstick” and red fins to attract mates during breeding season.

Southwestern Willow Flycatcher (Empidonax trailii extimus) Federally listed endangered species The Southwestern Willow Flycatcher occurs in dense riparian habitats along streams rivers, and other wetlands. At low elevations, the flycatcher breeds in dense, patchy habitats composed of mid-sized to tall trees and shrubs. At higher elevations, it occurs in dense stands of low to moderate height riparian shrubs. Vegetation density within 4m (13 ft) is especially important. Preferred habitats are almost always associated with standing or slow-flowing water. The destruction of riparian habitats has caused a severe decline in the populations of the southwestern willow flycatcher. Currently, this sub-species exists only in fragmented and scattered locations throughout its range. Historically, the breeding range reached from southern California, southern Nevada, southern Utah, Arizona, New Mexico, western Texas, southwestern Colorado, and northwestern Mexico. The flycatcher is a migratory bird that winters in Mexico, Central America, and northern South America. Currently, the breeding range for the flycatcher is similar to the historic range, though much of the riparian habitat in the southwest has been degraded by agricultural practices, invasion of non-native vegetation and urban development. The Southwestern Willow Flycatcher is an insectivore, taking insects from the air, or picking them from the foliage. The Southwestern Willow Flycatcher is present on breeding grounds by mid-May. By late May, nests are built, usually in a branched tree fork near the water. Typically, three eggs are laid and then incubated for 12-13 days.

Virgin spinedace (Lepidomeda mollispinis mollispinis) State conservation species Size: 5″ (12.7 cm) The Virgin spinedace looks, feeds, and behaves like a miniature trout. This silvery minnow gets its name from the sharp spiny rays in its dorsal fin. Virgin spinedace are found only in the Virgin River Basin. Unlike the woundfin and chub, which live only in the Virgin River, spinedace are also found throughout many tributary streams. Virgin Spinedace prefer deep pools and runs and are at home in both clear and turbid water.

Flannelmouth sucker (Catostomus latipinnis) State conservation species Size: 2+’ (64.8 cm) The flannelmouth sucker is the largest native fish in the Virgin River, growing over two feet in length and weighing over six pounds. The flannelmouth’s thick fleshy lips contain taste buds that help it find food along the bottom of the River, including aquatic invertebrates, organic debris and algae. Flannelmouth suckers are usually found in deep sandy areas of the Virgin River, but large numbers congregate in shallow gravel areas for spawning in the spring. Water in the river's lower valley provides irrigation for the cultivation of cotton, pomegranates, and figs.

The Nevada river valley's significance is commemorated by Nevada Historical Marker 56.