Western N. America, Brit. Columbia to Baja MX, east to Montana
"California blackberry provides food and cover for many wildlife species. Blackberries are eaten by numerous birds, including the ruffed grouse, northern bobwhite, sharp-tailed grouse, California quail, ring-necked pheasant, blue grouse, gray (Hungarian) partridge, band-tailed pigeon, American robin, yellow-breasted chat, pine grosbeak, gray catbird, and summer tanager. Jays, pigeons, northern mockingbird, sparrows, tanagers, thrashers, and towhees, consume the fruit of California blackberry and nest in its tangled branches. Mammals, such as the coyote, common opossum, skunks, gray fox, red fox, raccoon, squirrels, chipmunks, and black bear, consume the fruit of blackberries.
Black-tailed deer feed on the stems and foliage of California blackberry , and in some parts of California it is considered a preferred browse. In the Coast Range of western Oregon, leaves are selected by deer in all seasons except summer, when a wide variety of other foods are present. In many areas California blackberry is particularly important to deer during the fall and winter. Deer often feed heavily on the foliage until the leaves are covered by snow. The young leaves, which develop earlier than those of most other associated shrubs, provide an important food source when forage supplies are lowest and deer are threatened with malnutrition. Hines and Land report that California blackberry browse is a preferred winter food of black-tailed deer inhabiting Douglas-fir (Pseudotsuga menziesii) forests of the Oregon Coast Ranges. In this area it supplied nearly 50 percent of the total deer forage at the beginning of winter. In other winter feeding trials, deer reduced the leaves and twigs of California blackberry by as much as 80 to 89 percent.
Elk feed on California blackberry through much of the year in parts of California, although utilization appears to be highest during the fall and winter. Rabbits, porcupines, mountain beaver, and beaver occasionally consume the stems, leaves, and cambium of blackberries .
Blackberries, in general, provide only minimal browse for domestic livestock. In some locations, California blackberry is moderately grazed by domestic sheep but is rarely used by cattle...
California blackberry provides important cover for a wide variety of wildlife species. Dense thickets of blackberries form good nesting sites for many small birds including, thrashers, jays, pigeons, northern mockingbird, sparrows, tanagers, and towhees. The endangered least Bell's vireo frequently nests in California blackberry thickets along willow (Salix spp.)-cottonwood (Populus spp.)-oak (Quercus spp.) ecotones in certain riparian areas of California. Mammals such as rabbits, red squirrel, black bear, and beaver utilize blackberry thickets for cover in many areas." 
"Native Americans historically ate fresh blackberries in summer. Fruit was dried and combined with meat to make cakes which were eaten in winter. Unripened berries were soaked in water to make a cool refreshing drink, and leaves or vines were used in making teas. Roots were boiled in water to make various medicinal preparations. The fruit and stems of many blackberries have also been used to produce various tonics or medicines." 
"Blackberries, because of their ability to grow well on infertile soils, may be valuable in preventing soil erosion on some sites. California blackberry has been used to at least a limited extent in rehabilitation projects in the West...
Fruits of the California blackberry are sweet and edible. The commercially grown loganberry, youngberry, and boysenberry were originally derived from this species." 
 Tirmenstein, D. 1989. Rubus ursinus. In: Fire Effects Information System,. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.fed.us/database/feis/plants/shrub/ruburs/all.html.