Sacramento Fish & Wildlife Office
Species Account
RIPARIAN WOODRAT
(Neotoma fuscipes riparia)
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About usCLASSIFICATION: Federal Endangered Species (Federal Register 65:8881 (pdf); February 23, 2000)
CRITICAL HABITAT: Determined to be prudent. Will be designated when funding allows.
RECOVERY PLAN: Recovery plan for the upland species of the San Joaquin Valley, California (PDF), September 30. 1998.
DESCRIPTION:
The riparian woodrat (Neotoma fuscipes riparia), also known as the San Joaquin woodrat, is a medium sized rodent in the Cricetidae family. It is one of eleven subspecies of dusky-footed woodrats (N. fuscipes). Dusky-footed woodrats are predominantly gray and cinnamon above and whitish beneath. Their tails are well furred, not scaly like those of common nonnative black rats (Rattus rattus), which are in a completely different family, Muridae. Adult riparian woodrats weigh from about 7 to 14 ounces. The riparian woodrat can be distinguished from other subspecies by having white rather than dusky hind feet. It is also larger, lighter and more grayish. Its tail is more distinctly bicolored.
Riparian woodrats are most numerous where shrub cover is dense and least abundant in open areas. In riparian areas, highest densities of woodrats and their houses are often encountered in willow thickets with an oak overstory. They are common where there are deciduous valley oaks, but few live oaks.
Mostly active at night, the woodrat's diet is diverse and principally herbivorous, with leaves, fruits, terminal shoots of twigs, flowers, nuts, and fungi. The young are born in stick nest houses, or lodges, on the ground, which measure 2 to 3 feet high and 4 to 6 feet in diameter. Most lodges are positioned over or against logs. Unlike other subspecies, the riparian woodrat occasionally builds nests in cavities in trees and artificial wood duck nest boxes.
Find lots more information in the Draft Habitat Assessment Guidelines & Survey Protocol for the Riparian Brush Rabbit and the Riparian Woodrat (PDF).
DISTRIBUTION:
The riparian woodrat inhabits riparian communities along the lower portions of the San Joaquin and Stanislaus rivers in the northern San Joaquin Valley. Historical records for the riparian woodrat are distributed along the San Joaquin, Stanislaus, and Tuolumne rivers, and Corral Hollow, in San Joaquin, Stanislaus, and Merced counties.
Before the statewide reduction of riparian communities by nearly 90 percent, the riparian woodrat probably ranged throughout the extensive riparian forests along major streams flowing onto the floor of the northern San Joaquin Valley. Riparian woodrat populations today are greatly depleted, with the only known population at Caswell Memorial State Park with a possible second population near Vernalis, San Joaquin County.
THREATS:
Potential threats to this species include habitat conversion to agriculture, wildfire, disease, predation, flooding, drought, clearing of riparian vegetation, use of rodenticides and browsing and trampling by ungulates.
There\has been a statewide reduction of riparian communities by nearly 90 percent due to elimination and modification of riparian forests along valley floor river systems to urban, commercial, and agricultural development, wood cutting, reclamation and flood control activities, heavy groundwater pumping, river channelization, dam building, and water diversion.
REFERENCES FOR ADDITIONAL INFORMATION:
Katibah, E.F. 1984. A brief history of riparian forests in the Central Valley of California. In: R.E. Warner and K.M. Hendrix, eds. California riparian systems ecology, conservation, and productive management. Berkeley, CA: Univ. of California Press. 23-29.
U.S. Fish and Wildlife Service. 1998. Recovery plan for the upland species of the San Joaquin Valley, California. Portland, Oregon.
U.S. Fish and Wildlife Service. 2000. Endangered and Threatened Wildlife and Plants; Final Rule to List the Riparian Brush Rabbit and the Riparian, or San Joaquin Valley, Woodrat as Endangered. Portland, Oregon. (pdf)
Photo Credit: Moose Peterson©
