The North American beaver (Castor canadensis) had a historic range that overlapped the Sierra Nevada in California. Before the European colonization of the Americas, beaver were distributed from the arctic tundra to the deserts of northern Mexico. [1] The California Golden beaver subspecies (Castor canadensis subauratus) was prevalent in the Sacramento and San Joaquin River watersheds, including their tributaries in the Sierra Nevada. Recent evidence indicates that beaver were native to the High Sierra until their extirpation in the nineteenth century.
In 1916, Harold Bryant wrote in California Fish and Game, "The beaver of our mountain districts has been entirely exterminated and there are but a few hundred survivors to be found along the Sacramento, Colorado and San Joaquin Rivers." [2] Earlier, in 1906, Frank Stephens wrote in "California Mammals" that Castor canadensis' historic range was from the "Pacific slope from Alaska to central California east to and including the Sierra Nevada and Cascade Mountains" and adds "In most parts of California the presence of beavers is only made known by the stumps of the trees and saplings that they have cut." [3] McIntyre hypothesized that beaver were trapped out of the Sierra early in the nineteenth century by trappers before records could be kept. [4] Other early twentieth century naturalists (Grinnell, Tappe, etc.) questioned whether the California Golden beaver dwelt above 1,000 feet (300 m) of elevation in the Sierra. [5] [6] In 2012, physical evidence demonstrated that beaver were native to the Sierra until at least the mid-nineteenth century, via radiocarbon dating of buried beaver dam wood uncovered by deep channel incision in two locations in Red Clover Creek in the Feather River watershed. [7] That report was supported by a summary of indirect evidence of beaver including reliable observer accounts of beaver in multiple watersheds from the northern to the southern Sierra Nevada, including its eastern slope. [8]
California Golden beaver taken from Snelling, California (elevation 256 ft or 78 m and Waterford, California (elevation 51 ft or 16 m) were stocked in 1940 at Mather Station (elevation 4,522 ft or 1,378 m) west of Yosemite National Park and in 1944 at Fish Camp (elevation 5,062 ft or 1,543 m) by the California Department of Fish and Game (CDFG). These native "Central Valley" beaver have been building dams and rearing young successfully for 70 years in and near Yosemite at elevations higher than 5,000 feet (1,500 m). [4] A second reference confirms that the CDFG re-introductions of beaver into Mariposa County in the Merced River watershed were all C. C. subauratus (Golden beaver) taken from near sea level elevations. [9] These lowland beaver adapted to the high Sierra without difficulty.
Castor canadensis were re-introduced to the Tahoe Basin by the CDFG and the U. S. Forest Service between 1934 and 1949 in order to prevent stream degradation and to promote wetland restoration. Descended from no more than nine individuals from the Snake River in Idaho, 1987 beaver populations on the upper and lower Truckee River had reached a density of 0.72 colonies (3.5 beavers) per kilometer. [10]
As of 2023, the California Department of Fish and Game recognizes the ecosystem services provided by beavers across the state. [11] In cases where beavers are harming human property, the DFG will first attempt to educate the human party, and only then issue a limited permit to kill the beaver. [11]
Beaver have been documented in the upper and lower Truckee River, Ward Creek, Cold Creek, Taylor Creek, Meeks Creek, Blackwood Creek, and King's Beach, so the descendants of the original nine beavers have apparently migrated around most of Lake Tahoe. [12] [13] [14] A 2007 study of Taylor Creek showed that the beaver dam removal decreased wetland habitat, increased stream flow, and increased total phosphorus pollutants entering Lake Tahoe - all factors which negatively impact the clarity of the lake's water. [15] In addition, beaver dams located in Ward Creek, located on the west shore of Lake Tahoe, were also shown to decrease nutrients and sediments traveling downstream. [15]
In 1987, Beier reported that beaver had caused local extinction of Quaking aspen (Populus tremuloides) and Black cottonwood (Populus trichocarpa) on 4-5% of stream reaches on the lower Truckee River, however Willow (Salix spp.) showed good vigor despite heavy use in most reaches. He further speculated that without control of beaver populations that aspen and cottonwood could go extinct on the Truckee River. [16] However, not only have aspen and cottonwood survived ongoing beaver colonization but a recent study of ten Tahoe streams utilizing aerial multispectral videography has shown that deciduous, thick herbaceous, and thin herbaceous vegetation are more highly concentrated near beaver dams, whereas coniferous trees are decreased. [12]
Until recently, beaver were considered pests who caused flooding and impaired the passage of spawning trout and salmon. However, it has been shown that trout and salmon move freely across beaver dams. [17] The presence of beaver dams has also been shown to either increase the number of fish, their size, or both, in a study of brook, rainbow and brown trout in Sagehen Creek, which flows into the Little Truckee River at an altitude of 5,800 feet (1,800 m). [18]
Lake Tahoe is a freshwater lake in the Sierra Nevada of the Western United States, straddling the border between California and Nevada. Lying at 6,225 ft (1,897 m) above sea level, Lake Tahoe is the largest alpine lake in North America, and at 122,160,280 acre⋅ft (150.7 km3) it trails only the five Great Lakes as the largest by volume in the United States. Its depth is 1,645 ft (501 m), making it the second deepest in the United States after Crater Lake in Oregon.
The Truckee River is a river in the U.S. states of California and Nevada. The river flows northeasterly and is 121 miles (195 km) long. The Truckee is the sole outlet of Lake Tahoe and drains part of the high Sierra Nevada, emptying into Pyramid Lake in the Great Basin. Its waters are an important source of irrigation along its valley and adjacent valleys.
The Carson River is a northwestern Nevada river that empties into the Carson Sink, an endorheic basin. The main stem of the river is 131 miles (211 km) long although the addition of the East Fork makes the total length 205 miles (330 km), traversing five counties: Alpine County in California and Douglas, Storey, Lyon, and Churchill Counties in Nevada, as well as the Consolidated Municipality of Carson City, Nevada. The river is named for Kit Carson, who guided John C. Frémont's expedition westward up the Carson Valley and across Carson Pass in winter, 1844. The river made the National Priorities List (NPL) on October 30, 1990 as the Carson River Mercury Superfund site (CRMS) due to investigations that showed trace amounts of mercury in the wildlife and watershed sediments.
The Kickapoo River is a 126-mile-long (203 km) tributary of the Wisconsin River in the state of Wisconsin, United States. It is named for the Kickapoo Indians who occupied Wisconsin before the influx of white settlers in the early 19th century.
The Santa Ynez River is one of the largest rivers on the Central Coast of California. It is 92 miles (148 km) long, flowing from east to west through the Santa Ynez Valley, reaching the Pacific Ocean at Surf, near Vandenberg Space Force Base and the city of Lompoc.
Lahontan cutthroat trout is the largest subspecies of cutthroat trout, and the state fish of Nevada. It is one of three subspecies of cutthroat trout that are listed as federally threatened.
The Sisquoc River is a westward flowing river in northeastern Santa Barbara County, California. It is a tributary of the Santa Maria River, which is formed when the Sisquoc River meets the Cuyama River at the Santa Barbara County and San Luis Obispo County border just north of Garey. The river is 57.4 miles (92.4 km) long and originates on the north slopes of Big Pine Mountain, at approximately 6,320 feet (1,930 m). Big Pine Mountain is part of the San Rafael Mountains, which are part of the Transverse Ranges.
Deer Creek is a 60-mile-long (97 km) southwestward-flowing stream in Northern California that flows through Tehama County, California. It is an eastside tributary of the Sacramento River. As one of only three remaining Sacramento River tributaries supporting native runs of the genetically distinct Central Valley spring-run Chinook salmon, it is a stronghold for this state and federally endangered fish as well as other salmonids.
Pescadero Creek is a major stream in Santa Cruz and San Mateo counties in California, United States. At 26.6 miles (42.8 km), it is the longest stream in San Mateo County and flows all year from springs in the Santa Cruz Mountains. Its source is at 1,880 feet (570 m) above sea level on the western edge of Castle Rock State Park, with additional headwaters in Portola Redwoods State Park, and its course traverses Pescadero Creek County Park and San Mateo County Memorial Park before entering Pescadero Marsh Natural Preserve at Pescadero State Beach and thence to the Pacific Ocean 14.4 miles (23 km) south of Half Moon Bay.
Alhambra Creek is a stream in Contra Costa County, in the East Bay region of the San Francisco Bay Area in northern California.
Martis Creek is a northward-flowing stream originating on Sawtooth Ridge, west of the peak of Mount Pluto in Placer County, California, United States. After crossing into Nevada County, California, it is a tributary to the Truckee River on the eastern side of Truckee.
Weister Creek is a stream, some 25 miles (40 km) long, in Vernon County in southwestern Wisconsin in the United States and is a tributary of the Kickapoo River. It lies in the Driftless Area which is characterized by hills and valleys apparently missed by the last glacial advance during the Pleistocene. Much of the lower half of Weister Creek is surrounded by wetlands and lies in the Kickapoo Valley Reserve.
Red Clover Creek is a west-northwestward-flowing stream originating on Horton Ridge east of the Sierra Nevada crest in Plumas County, California, United States. It courses 27 miles (43 km) through Dotta Canyon and Red Clover Valley to its confluence with Last Chance Creek in Genesee Valley, just above its confluence with Indian Creek, which flows into the East Branch North Fork Feather River. The Red Clover Valley sits at an elevation of about 5,400 feet (1,600 m) and is located on the east side of the Sierra Nevada crest, approximately 60 miles (97 km) north of Truckee and 30 miles (48 km) east of Quincy.
Griff Creek is a southward-flowing stream originating on Martis Peak in Placer County, California, United States. It culminates in north Lake Tahoe at Kings Beach, California.
Trout Creek is a northward-flowing stream originating on the west side of Armstrong Pass on the Carson Range in El Dorado County, California, United States.
Trout Creek is a small tributary of the Truckee River draining about 5.1 square miles (13 km2) along the eastern crest of the Sierra Nevada. It originates east of Donner Ridge and north of Donner Lake in the Tahoe–Donner Golf Course and flows through the town of Truckee, California, to its confluence with the Truckee River in Nevada County, California, just west of Highway 267.
Brown's Creek is a 9.7-mile-long (15.6 km) stream which originates about 5.5 miles northwest of the city of Stillwater and flows south for about half its length then east to its confluence with the St. Croix River just north of Stillwater in Washington County, Minnesota, United States. It is one of few creeks in the Minneapolis – Saint Paul "Twin Cities" metropolitan area that supports a fishable trout population.
Taylor Creek is a 2.2-mile-long (3.5 km) northward-flowing stream originating in the Fallen Leaf Lake and culminating at Baldwin Beach at Lake Tahoe, about 1 mile (1.6 km) west of Camp Richardson in El Dorado County, California.
Independence Lake is a natural glacial lake in the Sierra Nevada of California. At an elevation of 6,949 feet (2,118 m) in the upper reaches of the Truckee River basin, it has been less affected by development than most lakes in the area. The Nature Conservancy owns a 2,325 acres (9.41 km2) parcel of land around it, which it manages privately as the Independence Lake Preserve for the purposes of conservation and low-impact recreation.
The beaver is a keystone species, increasing biodiversity in its territory through creation of ponds and wetlands. As wetlands are formed and riparian habitats enlarged, aquatic plants colonize newly available watery habitat. Insect, invertebrate, fish, mammal, and bird diversities are also expanded. Effects of beaver recolonization on native and non-native species in streams where they have been historically absent, particularly dryland streams, is not well-researched.