The cover value of grouse whortleberry is variable. Because of its low growth form, grouse whortleberry provides minimal hiding or thermal cover for large mammals. Cover value may be higher for small birds and mammals. In northern Utah, subalpine fir/grouse whortleberry communities provide resting sites for elk [86]. In eastern Idaho and western Wyoming, lodgepole pine stands with abundant grouse whortleberry serve as resting sites for deer, elk, moose, and grizzly bear [16,117]. Cover value of grouse whortleberry has been rated as follows [36]. CO MT UT WY Small mammals fair poor good good Small nongame birds poor poor fair good Upland game birds ---- poor fair fair Waterfowl ---- ---- poor poor
Grouse whortleberry is a low, rhizomatous, usually matted, slow-growing native shrub that reaches 4 to 20 inches (10-51 cm) in height. Plants are multi-branched from the base and broomlike in appearance. The small, thin leaves are deciduous; flowers are urn-shaped and inconspicuous. Berries are 0.12 to 0.2 inch (3-5 mm) broad [43,58,97,129,140].
Most Vaccinium spp. lack a taproot but have fine, threadlike lateral roots [74]. Roots of grouse whortleberry grow to a depth of about 16 inches (40 cm). Rhizomes occur in duff, or at the interface of duff and mineral soil, and are restricted to the upper 4 inches (10 cm) of soil [40,87].
Grouse whortleberry grows from British Columbia, mostly east of the Cascades, southward to California. It extends eastward to Alberta and Montana and occurs throughout the Rocky Mountains southward to Colorado, Utah, and northern New Mexico [59]. A disjunct population of grouse whortleberry grows in the Black Hills of South Dakota [18,62]. The Natural Resources Conservation Service provides a map of grouse whortleberry's distribution in the United States (https://plants.usda.gov /).
Although the seed is generally viable, postfire regeneration of grouse whortleberry from seed is rare because germinants are fragile. The species relies on prolific rhizomes to survive fire. Following low- or moderate-severity fires that do not kill the shallow rhizomes, grouse whortleberry sprouts quickly and vigorously. The rhizomes occur in duff or at the duff-soil interface [25,39,87,109,115]. Severe fires can eliminate this shrub from a site [115]. Please refer to the Fire Effects section of this report for more information.
WildFIRE REGIMES in forests where grouse whortleberry is common are variable in frequency and severity, including nonlethal understory, severe stand-replacement, and mixed-severity fires [17].
Persistent (rather than seral) lodgepole pine forests in northern Idaho and western Montana have mean stand-replacing fire intervals of 195 years, with low-severity fires at 40- to 50-year intervals. Grouse whortleberry cover often exceeds 50% in these stands [115].
Fire return intervals for crown fires in the high, volcanic plateau lodgepole pine forests of Yellowstone National Park were estimated at 300 to 400 years. The more frequent low-severity surface fires are thought to exert a minor influence on long-term vegetation structure. After the slow development of sufficient large fuels (largely lodgepole pine, subalpine fir, and Engelmann spruce), stand-replacing fires are probably ignited in small fuels by lightning strikes. In these forests, grouse whortleberry decreases as fire severity increases [108,123].
Drier montane sites, dominated by lodgepole pine and whitebark pine, often have stand-replacing fire return intervals greater than 200 years [13,91]. Where whitebark pine is climax, fires are infrequent and generally of low intensity. When fires do occur, many trees die and regeneration is low [91].
FIRE REGIMES:
FIRE REGIMES for plant communities and ecosystems in which grouse whortleberry is likely to occur are summarized below. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Community or Ecosystem Dominant Species Fire Return Interval Range (years) silver fir-Douglas-fir Abies amabilis-Pseudotsuga menziesii var. menziesii > 200 grand fir Abies grandis 35-200 western larch Larix occidentalis 25-100 Engelmann spruce-subalpine fir Picea engelmannii-Abies lasiocarpa 35 to > 200 whitebark pine* Pinus albicaulis 50-200 [17] Rocky Mountain lodgepole pine* Pinus contorta var. latifolia 25-300+ [8,108] western white pine* Pinus monticola 50-200 Rocky Mountain ponderosa pine* Pinus ponderosa var. scopulorum 2-10 Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 mountain hemlock* Tsuga mertensiana 35 to > 200 [17] *fire return interval varies widely; trends in variation are noted in the species review In seral Rocky Mountain lodgepole pine forests in northern Idaho, grouse whortleberry is widespread. Fuel loadings are discontinuous and may be heavy, enhanced by deep duff and subalpine fir and mountain hemlock regeneration. Management-ignited fire is used to increase water yield, provide wildlife forage, prepare seedbeds for regeneration, and reduce fuels. Duff moisture content is an important fire management consideration. Intense soil heating in these forests kills the roots and rhizomes of shrubs and herbs, notably Vaccinium species [115].
In persistent or climax upper-elevation Rocky Mountain lodgepole pine forests in northern Idaho, where grouse whortleberry cover is abundant, fuel loadings are often light and discontinuous. Elevation of these stands is above 5,000 feet (1,500 m). Unlike seral lodgepole pine forests which usually have a strong understory of shade-tolerant subalpine fir, these stands have only scattered subalpine fir. Litter and duff are shallow. Prescribed fire is used on these sites for hazard reduction and site preparation related to logging [115]. Upper-elevation, persistent Rocky Mountain lodgepole pine forests with abundant grouse whortleberry also occur in western Wyoming, southeastern Idaho, and western Montana [99,116].
In northern Idaho's highest subalpine forests, grouse whortleberry is a common component under a mixed overstory. Tree species include Rocky Mountain lodgepole pine, whitebark pine, Engelmann spruce, subalpine fir and mountain hemlock. Fuels are characterized by sparse fine materials and moderate to heavy loadings of larger fuels. Management objectives are similar those listed above, but timber production is rarely important. Fire return intervals are long, more so because of fire suppression. These forests are susceptible to fires that originate at lower elevations as well as fires that ignite on site [115]. Grouse whortleberry can increase the flammability of litter and influence the spread of surface fires by lending physical support to fine fuels such as twigs and conifer needles, creating a better aerated, loose surface layer. The shrub contributes to combustion once preheating is overcome. Regression equations have been developed to describe the fuel characteristics of grouse whortleberry [3,38].
Grouse whortleberry is one of the most prominent understory species in the subalpine zone of the Rocky Mountains [1,82]. The species is common in coniferous forests, ravines, or on open slopes across a relatively wide geographical and elevational range [59,76,112,131].
Sites dominated by grouse whortleberry are characterized by heavy snowpack, although early season snowmelt is common. In many areas, the potential for drought exists by midsummer. These sites are usually cool to cold with a very short growing season [46,48,76].
Grouse whortleberry grows on dry to moist, well drained, rocky, sandy and gravelly loams [6,33,54,56,112]. Vaccinium spp. require acidic soils and thrive where pH ranges from 4.3 to 5.2. These shrubs require relatively low amounts of many essential elements and are capable of growing on soils with low fertility [74].
Grouse whortleberry has a wide elevational range [139]. Ranges reported in the literature are as follows:
6,000 to 7,200 feet (1800-2,200 m) in California [58]
8,500 to 12,500 feet (2,590-3,810 ) in Colorado [49]
4,800 to 9,000 feet (1,460-2,740 m) in Montana [96,99]
7,870 to 8,360 feet (2,400-2,550 m) in Wyoming [65]
205 Mountain hemlock
206 Engelmann spruce-subalpine fir
207 Red fir
208 Whitebark pine
210 Interior Douglas-fir
211 White fir
212 Western larch
213 Grand fir
215 Western white pine
218 Lodgepole pine
219 Limber pine
224 Western hemlock
227 Western redcedar-western hemlock
237 Interior ponderosa pine
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES22 Western white pine
FRES23 Fir-spruce
FRES24 Hemlock-Sitka spruce
FRES25 Larch
FRES26 Lodgepole pine
FRES37 Mountain meadows
K003 Silver fir-Douglas-fir forest
K004 Fir-hemlock forest
K005 Mixed conifer forest
K007 Red fir forest
K011 Western ponderosa forest
K012 Douglas-fir forest
K014 Grand fir-Douglas-fir forest
K015 Western spruce-fir forest
K016 Eastern ponderosa forest
K017 Black Hills pine forest
K018 Pine-Douglas-fir forest
K020 Spruce-fir-Douglas-fir forest
K021 Southwestern spruce-fir forest
216 Montane meadows
Grouse whortleberry is described as moderately resistant to fire [39,135]. Underground rhizomes generally survive low- to moderate-severity fires that do not consume the lower duff [39]. However, most grouse whortleberry rhizomes extend no deeper than between duff and mineral soil [40,87]. Because rhizomes are shallow, this shrub is susceptible to severe, duff-reducing fires that eliminate rhizomes and seriously damage or kill the plant [64,77].
Grouse whortleberry provides food and cover for many wildlife species. Lodgepole pine, spruce, fir, and mountain hemlock forests with a grouse whortleberry understory provide good summer range for many large mammal species throughout much of the West [6,48,54,62,85,90,128]. Higher-elevation sites in grouse whortleberry communities may be poor wintering areas for large mammals because of heavy snow accumulations and the absence of tall to medium shrubs [29].
The abundance and availability of grouse whortleberry contribute to its overall value, although it is less palatable than many other shrubs. Grouse whortleberry is considered an intermediate elk browse in northwestern Wyoming and is eaten by elk on summer ranges of northern Utah [14,23]. Grouse whortleberry is an important component of mule deer diets in parts of Utah and Colorado [23,27,34,104] and is an important fall moose food throughout the Intermountain West [98]. In parts of Montana grouse whortleberry is the most important shrub in the summer diet of Rocky Mountain goats [,111]. Bears may rely heavily on Vaccinium berries and foliage [85].
Berries of grouse whortleberry are a valuable food source for many birds and small mammals. Chipmunks, red squirrel, gray fox, red fox, and skunks readily feed on grouse whortleberries. Spruce grouse, ptarmigans, ruffed grouse, blue grouse, bluebirds, thrushes, and other birds commonly consume whortleberries [72,83,115,128].
Grouse whortleberry provides only minimal browse for most classes of livestock [72,115]. However, it provides fair to good browse for domestic sheep in the Blue Mountains of Oregon [33].
Grouse whortleberry often dominates the shrub layer of subalpine
forests throughout the Rocky Mountains. Common overstory dominants are subalpine fir (Abies lasiocarpa), Rocky Mountain lodgepole pine (Pinus contorta var. latifolia), mountain hemlock (Tsuga mertensiana), whitebark pine (P. albicaulis), Douglas-fir (Pseudotsuga menziesii), Engelmann spruce (Picea engelmannii), white spruce (P. glauca), grand fir (A. grandis), western larch (Larix occidentalis), western redcedar (Thuja plicata), and limber pine (P. flexilis) [41,99,115,118,122,137]. Grouse whortleberry also grows in association with subalpine larch (L. lyallii) in Montana [9] and interior ponderosa pine (P. ponderosa var. scopulorum) in the Black Hills [62,127]. In the Cascade Mountains of Oregon, grouse whortleberry occurs commonly with mountain
hemlock, Shasta red fir (A. magnifica var. shastensis), western white pine (P. monticola), and Pacific silver fir (A. amabilis) [89].
In the Rocky Mountains common understory associates of grouse whortleberry include twinflower (Linnaea borealis), queencup beadlily (Clintonia uniflora), beargrass (Xerophyllum tenax), prince's pine (Chimaphila umbellata), lupine (Lupinus spp.), woodrush (Luzula hitchcockii), western meadowrue (Thalictrum occidentale), bluejoint reedgrass (Calamagrostis canadensis), pinegrass (C. rubescens), sedges (Carex spp.), and heartleaf arnica (Arnica cordifolia). Associated woody species include big huckleberry (V. membranaceum), dwarf bilberry (V. myrtillus), bearberry (Arctostaphylos uva-ursi), pachistima (Pachistima myrsinites), menziesia (Menziesia ferruginea), snowberry (Symphoricarpos spp.), gooseberries (Ribes spp.), and Oregon-grape (Mahonia repens) [14,21,60,99,115,118].
Common associated species reported for Oregon and Washington include queencup beadlily, twinflower, woodrush, pinegrass, beargrass, sedges, bearberry, big huckleberry, menziesia, dwarf huckleberry (Vaccinium caespitosum), bunchberry (Cornus canadensis), Cascade's rhododendron (Rhododendron albiflorum), white spirea (Spiraea betulifolia), and red mountainheath (Phyllodoce empetriformis) [66,68]
Because grouse whortleberry is frequent and abundant in the understory of late-seral, climax, or old-growth montane forests, many published vegetation classifications include it as a community indicator or dominant. A partial list of references is included below by state.
Arizona [90]
Colorado [5,12,35,56,57,60,61,73,136]
Idaho [24,32,118]
Montana [99,110]
New Mexico [35,90]
Oregon [11,41,45,47,53,54,63,67,133]
South Dakota [62,119]
Utah [55,92]
Washington [2,31,32,41,45,47,141]
Wyoming [62,102,103,136,142]
Vaccinium foliage is relatively high in carotene and energy content
[30]. Protein value of grouse whortleberry browse is rated as fair
[36]. Fruit of species within this genus are typically sweet and
contain high concentrations of both mono- and disaccharides [121] and are high in vitamin C [105]. Fruit of grouse whortleberry is high in energy value [100].
AZ CA CO ID MT NV
Fruits of grouse whortleberry are edible, though small and difficult to gather in quantity. Berries may be eaten fresh, cooked, or made into jam and wine. Vaccinium spp. fruits were an important traditional food for many Native American peoples. Leaves were used to make beverages [50,95].
Grouse whortleberry browse is at least moderately palatable to
wild ungulates in many areas [,46]; however, Young and Robinette
[143] report that it is of very low palatability to elk in the Selway River
drainage of Idaho. Palatability to domestic livestock appears to be
poor [72,115]. Palatability of grouse whortleberry browse has been rated as follows [33,36]:
Grouse whortleberry flowers in early to midsummer. Fruit maturation begins immediately after flowering, and fruit is generally ripe by late summer or fall [43,126].
Phenological development was documented as follows during a study in the northern Rockies [113]: East of the Continental Divide - MT and Yellowstone NP leaf leaves flower flower fruit seed leaves bud full starts ends ripe fall fallen burst grown starts average 5/17 6/12 6/8 6/26 8/7 8/13 9/28 earliest 4/30 5/21 5/1 5/10 7/22 8/3 9/12 latest 6/30 7/25 7/4 7/21 8/15 8/20 10/24 Northern Idaho and western Montana - leaf leaves flower flower fruit seed leaves bud full starts end ripe fall fallen burst grown start average 5/3 5/26 5/17 6/2 7/21 8/14 10/4 earliest 3/27 4/25 4/15 5/15 7/5 8/10 9/5 latest 5/28 6/30 6/12 7/2 8/29 8/23 10/16
Postfire response of grouse whortleberry is related to fire severity and intensity. Initial declines in cover have been noted [10,21,109]. After severe, stand-replacing crown fires, the species can recover (from rhizomes) in as little as 5 years [68,87]. In a western Montana lodgepole pine forest, grouse whortleberry was the most ubiquitous plant species detected 12 years and 21 years after a severe burn. Percent cover of grouse whortleberry after 21 years averaged from 1% to 33%. The higher percent cover was in areas undisturbed by postfire management activity, identified as road building, salvage logging, pole cutting, cattle grazing, and herbicide use, which were characterized as "calamitous" for grouse whortleberry recovery [78].
In a Wyoming study postfire sprout density of grouse whortleberry declined with increasing fire severity. In that study, all grouse whortleberry plants observed were from sprouting rhizomes. No seedlings were observed, in either burned or unburned sites [123].
Rhizomatous shrub, rhizome in soil
Initial-offsite colonizer (off-site, initial community)
Grouse whortleberry reproduces through seed and vegetatively through rhizome sprouting. The edible berries contain many seeds that are probably dispersed by birds and mammals.
Vaccinium seeds are not dormant. Seedlings may emerge 1 month after dispersal and continue to emerge for long periods without cold temperatures. Seedlings of most western Vacciniums are apparently rare in the field. Seedling establishment may be important only on good sites during "favorable" years [26,109].
Grouse whortleberry sprouts from rhizomes growing in the forest floor [87]. Because they are relatively shallow, rhizomes are vulnerable to fires of high severity and mechanical treatments that include severe soil scarification [10,68].
1 Northern Pacific Border
2 Cascade Mountains
3 Southern Pacific Border
4 Sierra Mountains
5 Columbia Plateau
6 Upper Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
15 Black Hills Uplift
Grouse whortleberry occurs as a seral or climax dominant in many high-elevation conifer forests [10,76,84,99,110]. In some high-elevation mountain hemlock or subalpine fir-lodgepole pine forests, grouse whortleberry declines as the overstory canopy closes [44,63].
In southwestern Montana, whitebark pine/grouse whortleberry overstories are relatively even-aged and can reach 400 to 600 years in age between stand-replacing disturbances. Nonlethal underburns occur more frequently than stand-replacing fires [13,91]; grouse whortleberry persists through low-severity fires. Please refer to the Fire Ecology and Fire Effects sections of this report for more information.
Following clearcutting that does not lead to heavy mechanical scarification in Rocky Mountain lodgepole pine stands, grouse whortleberry often sprouts and occupies a prominent role in seral communities. With moderately heavy site or slash treatments, grouse whortleberry decreases dramatically. High initial cover of species such as fireweed (Epilobium angustifolium) and pearly everlasting (Anaphalis margaritacea) often develops immediately after disturbance in many Rocky Mountain lodgepole pine-subalpine fir communities of western Montana. However, these understories succeed to grouse whortleberry and beargrass as the pole canopy develops [10]. Although lodgepole pine is often regarded as a seral species, some lodgepole pine/grouse whortleberry communities of the northern Rockies a represent an edaphic vegetation climax [34].
The currently accepted scientific name of grouse whortleberry is
Vaccinium scoparium Leib. (Ericaceae) [59,71,129,140].
Grouse whortleberry has been rated as having low value for short-term rehabilitation projects and moderate value for long-term rehabilitation. Its fibrous root system probably prevents soil erosion on some sites [36]. Species within the genus can be propagated from cuttings [26], but propagation of grouse whortleberry from seed is difficult. Seedlings are rare in the field [64,109].
Seeds of grouse whortleberry, collected from ripe berries, germinated on laboratory petri plates within 1 month but were very fragile and vulnerable to desiccation. Efforts to transplant the seeds to pots failed. The authors found no grouse whortleberry seedlings in field sites where the berries were collected. They concluded that the absence of seedlings was related to mortality of seeds or seedlings or to inadequate seed dispersal, rather than lack of seed production or seed viability [109].
Vaccinium scoparium is a species of huckleberry known by the common names grouse whortleberry, grouseberry, and littleleaf huckleberry.
It is native to western North America, primarily in the Rockies, Cascades, and Black Hills from British Columbia and Alberta south to far northern California to Colorado and New Mexico, and east to South Dakota.[3] It grows in mountain habitat such as forests, meadows, and talus, occurring in subalpine and alpine climates at elevations of 700 to 3000 meters (2,333 - 10,000 feet. It is a common understory plant in many forested regions of the Rocky Mountains, being common to abundant in some areas.[4]
Vaccinium scoparium is a squat, bushy rhizomatous shrub growing not more than half a meter (20 inches) in maximum height. It is matted and clumpy, and it spreads outward with the stems rooting at nodes where it comes in contact with moist substrate. The branches are broomlike when leaflike and new green twigs have sharp angles. The deciduous leaves are alternately arranged, the serrated oval leaf blades up to 1.5 centimeters (0.6 inches) in length.
Solitary flowers occur in the leaf axils. Each is about 4 millimeters (0.16 inches) long, urn-shaped, and pink.
The fruit is a soft, bright red berry up to 6 millimeters in width. It has a tart flavor.[5]
This shrub provides food for many large mammal species, such as elk, mule deer, and bears, and many smaller animals, such as squirrels, foxes, skunks, and a variety of birds.[4]
The berries are edible[6] and were used for food by many Native American groups, including the Kootenay, Okanogan, and Shuswap. They are small and difficult to collect in large quantities, and Native people likely used combs made of wood or fishbones to harvest them.[4][5]
Vaccinium scoparium is a species of huckleberry known by the common names grouse whortleberry, grouseberry, and littleleaf huckleberry.
It is native to western North America, primarily in the Rockies, Cascades, and Black Hills from British Columbia and Alberta south to far northern California to Colorado and New Mexico, and east to South Dakota. It grows in mountain habitat such as forests, meadows, and talus, occurring in subalpine and alpine climates at elevations of 700 to 3000 meters (2,333 - 10,000 feet. It is a common understory plant in many forested regions of the Rocky Mountains, being common to abundant in some areas.
