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Arctostaphylos rubra

• INTRODUCTORY
• DISTRIBUTION AND OCCURRENCE
• BOTANICAL AND ECOLOGICAL CHARACTERISTICS
• FIRE ECOLOGY
• FIRE EFFECTS
• MANAGEMENT CONSIDERATIONS
• REFERENCES

INTRODUCTORY

• AUTHORSHIP AND CITATION
• FEIS ABBREVIATION
• NRCS PLANT CODE
• COMMON NAMES
• TAXONOMY
• SYNONYMS
• LIFE FORM
• FEDERAL LEGAL STATUS
• OTHER STATUS

DISTRIBUTION AND OCCURRENCE

• GENERAL DISTRIBUTION
• HABITAT TYPES AND PLANT COMMUNITIES

Red fruit bearberry is a frequent shrub associate in boreal and subalpine spruce (Picea spp.) woodlands and forests. It is not usually a dominant understory species in spruce ecosystems [2,6,15,87,95]. Peinado and others [62] describe red fruit bearberry as "characteristic" of boreal spruce forests. Studies in white spruce (P. glauca) stands across boreal North America found red fruit bearberry had mean cover of <2%. It was not among the 15 most common species in the dwarf shrub-herb stratum [46]. It also occurs in boreal mixed spruce-tamarack (Larix laricina) associations [61]. Red fruit bearberry abundance in northern ecosystems may increase to the west. It is a common associate in white spruce taiga of Alaska and western Canada [18] and is sometimes "abundant" in black spruce (P. mariana) taiga [50]. Red fruit bearberry was dominant in a subarctic black spruce/littletree willow-bog Labrador tea (Salix arbusculoides-Ledum groenlandicum)-red fruit bearberry/splendid feather moss (Hylocomium splendens) community near Fort Worth, Northwest Territories [21]. In a vegetation survey along the Alaska Highway in Yukon, however, red fruit bearberry was "characteristic" but not dominant in wet spruce forests [59].

Red fruit bearberry grows in Rocky Mountain lodgepole pine (Pinus contorta var. latifolia) forests of Banff and Jasper National Parks, Alberta [45], in Engelmann spruce (Picea engelmannii) forests of British Columbia [35,85], and near white spruce swamps in Wyoming [39].

Red fruit bearberry occurs in and may dominate the understory of balsam poplar (Populus balsamifera subsp. balsamifera) floodplains in northern Alaska (Hettinger and Janz 1974, cited in [10]).

Red fruit bearberry occurs in and may dominate tundra dwarf heath and other tundra shrub communities of Alaska and northwestern Canada [26]. Dwarf shrub communities typically occupy only a few hundred square meters and are surrounded by other tundra vegetation types, usually spruce woodlands and forests [7]. Red fruit bearberry grows in willow/water sedge (Salix myrtillifolia and/or S. planifolia/Carex aquatilis) shrublands along the Alaskan Highway in Yukon [59] and in grayleaf willow (S. glauca) communities of the coastal plain of central arctic Alaska [89] and southwestern Yukon [15]. Red fruit bearberry is codominant in low shrub bog birch-red fruit bearberry/snow lichen (Cetraria nivalis) tundra in Mackenzie Valley, Northwest Territories [95].

Red fruit bearberry is commonly found in mountain-avens (Dryas spp.) communities of alpine and arctic Alaska [29]. In arctic regions, red fruit bearberry occurs or dominates in arctic mountain-avens (Dryas integrifolia) cushion-plant tundra [42,94]. Alaska willow (S. alaxensis) and/or russet buffaloberry (Shepherdia canadensis) are common codominants or associates [94].

The following vegetation classifications describe plant communities in which red fruit bearberry is a dominant species.

• grayleaf willow/red fruit bearberry open low shrub communities of the northern, interior, and south-central parts of the state
• red fruit bearberry ericaceous dwarf scrub tundra of western, interior, and arctic Alaska [85]
• eightpetal mountain-avens (D. octopetala)-red fruit bearberry-Lapland rosebay (Rhododendron lapponicum) prostrate shrub communities on stable dunes along the Atigun River [88]

• Engelmann spruce/red fruit bearberry/cup lichen (Cladonia cariosa-C. pyxidata) community on old recessional moraines of Jasper National Park [12]

• white spruce/mountain alder (Alnus viridis subsp. crispa)-red fruit bearberry association on floodplains and elevated plains in the Mackenzie Delta [61]

• white spruce/red fruit bearberry/ribbed bog moss (Aulacomnium palustre) vegetation type along the Alaskan Highway [59,76]
• white spruce/red fruit bearberry-Lapland rosebay/ribbed bog moss vegetation type along the Alaskan Highway
• white spruce/red fruit bearberry/abietinella moss (Abietinella abietina) vegetation type along the Alaskan Highway [76]
• red fruit bearberry-sheathed cottonsedge-northern Labrador tea (Eriophorum vaginatum- Ledum palustre) dwarf shrub tundra community along the Demptser Highway [75]
• eightpetal mountain-avens-red fruit bearberry-parasol whitetop (Doellingeria umbellata ) tundra on north-facing midslopes in the Doll Creek area of extreme northeastern Yukon [68]

BOTANICAL AND ECOLOGICAL CHARACTERISTICS

• GENERAL BOTANICAL CHARACTERISTICS
• RAUNKIAER LIFE FORM
• REGENERATION PROCESSES
• SITE CHARACTERISTICS
• SUCCESSIONAL STATUS
• SEASONAL DEVELOPMENT

Red fruit bearberry is a prostrate, dwarf shrub [1], about 1 to 6 inches (3-15 cm) tall [1,87]. Leaves are considered deciduous [14,74] or, more accurately, marcescent, meaning they tend to wither and whiten with age but persist on the stem [51,74]. Leaves are 0.8 to 2.4 inches (2-6 cm) long [74]. The inflorescence is a glandular, hairy raceme [87]. Flowers are arranged in small clusters of 1 to 6 [74]; they are about 0.25 inch (6 mm) long [87]. The fruit is a drupe [74]. Red fruit bearberry forms trailing mats [90] via spread from stolons [90] or rhizomes [34,71]. Lateral stem habit is not well distinguished for red fruit bearberry. It is possible that lateral stems of red fruit bearberry grow both above ground (stolons) and below ground (rhizomes), depending upon topography, soil movement, and/or genetic make-up of individual plants. Further studies are needed on stem habit of red fruit bearberry.

Red fruit bearberry is described as "long lived" [90].

Seed dispersal: Bears, other mammals, and birds eat red fruit bearberry fruits (see Importance to Wildlife and Livestock); presumably, these frugivorous animals disperse the seeds in their droppings.

Seed banking: Although information specific to red fruit bearberry was lacking as of 2008, bearberries and manzanitas (Arctostaphylos spp.) generally maintain a soil seed bank [56]. In Alaska, red fruit bearberry seedlings established from planted seed 1 or 2 years after sowing [13], suggesting that red fruit bearberry can establish from soil-stored seed.

Germination: Red fruit bearberry embryos are dormant. Scarification of the seedcoat and/or overwinter cold stratification are required to break dormancy [13,90]. In the laboratory, stratification for 60 to 90 days at 36 to 41 °F (2-5 °C) broke dormancy [90]. Seeds can germinate at low temperatures (41-77 °F (2-25 °C)) [13,90]. Light enhanced germination in an Alaskan field experiment [13]. Fire scarification typically breaks dormancy of bearberries and manzanitas [56]; however, no information was available on the effects of fire on red fruit bearberry seeds as of 2008.

Seedling establishment/growth: Red fruit bearberry established from seed in an area where a debris pile had been removed from an arctic coastal plain in Alaska. Four years after removal, red fruit bearberry had trace coverage and 1% frequency [20].

Vegetative regeneration: Red fruit bearberry sprouts [8,24,71] from stolons [90] or rhizomes [34] following top-kill. Sprout origin is not well described in much of the literature describing red fruit bearberry sprouting. Further studies are needed on red fruit bearberry's ability to regenerate vegetatively.

Soils: Red fruit bearberry prefers moist to wet soils [30,59,76], (review by [90]), although drainage may vary from good to poor [30], (review by [90]). On sites in northeastern British Columbia and southeastern Yukon, red fruit bearberry was most common on wet sites with a black spruce overstory, while prickly rose and kinnikinnick (Arctostaphylos uva-ursi) were more common on dry to moist sites with a Rocky Mountain lodgepole pine-black spruce overstory [60]. On lowlands on the western shore of the Hudson Bay, red fruit bearberry had greatest coverage (10%) on a poorly drained site with permafrost 35 inches (90 cm) beneath the soil surface [69].

Red fruit bearberry typically grows in loams, sands, or gravels [30,90] of variable pH [30,59,75]. A permafrost layer underlies the soil on many red fruit bearberry sites [80]. On the Tetlin National Wildlife Refuge in southeastern Alaska, red fruit bearberry grows in a 6- to 18-inch (15-45 cm)- deep organic soil layer that overlies alluvial mineral soil. Permafrost occurs about 12 inches (30 cm) below the organic soil layer [41]. In Yukon, red fruit bearberry is typical on low-lying terrain with underlying permafrost. Soil texture is variable, with the organic layer at a depth of 16 inches (40 cm) or more [59]. Red fruit bearberry-sheathed cottonsedge-northern Labrador tea communities in Yukon generally occur on sandy clay with stones, with an organic horizon up to 4 inches (10 cm) thick. The permafrost layer is 15 to 22 inches (39-55 cm) deep. Soil pH ranges from 3.4 to 3.9. White spruce/red fruit bearberry communities in Yukon often occur on sands, silts, and/or gravels with organic layers 2 to 18 inches (4-45 cm) deep, over permafrost. Soil pH ranges from 5.7 to 7.0 and slopes are moderate [76]. White spruce/mountain alder-red fruit bearberry floodplain communities in the Mackenzie River Delta region have a soil pH range of 8.0 to 8.2 [61]. In Ontario, red fruit bearberry occurs on sandy and gravelly beach ridges, calcareous till, and clay riverbanks [74]. In the Swamp Lake Botanic Area of Wyoming, red fruit bearberry occurs on moist, calcareous sites bordering white spruce swamps [39].

In an analysis of 95 sites across northwestern and north-central Canada, red fruit bearberry occurred most often on calcareous, fine-textured loams in low arctic and high subarctic tundra shrublands in northwestern Canada. Moisture regime was borderline between wet-mesic and mesic [81].

Topography and elevation: Red fruit bearberry often occurs on gentle terrain [30,49,59,75], although slopes in alpine locations may be steep. Red fruit bearberry typically grows near treeline [86]. In a floristic study of arctic and alpine plants of North America, Raup [67] usually found red fruit bearberry at timberline. Because the elevation of treeline increases with decreasing latitude, red fruit bearberry occurs at the highest elevations in its southern distribution, while it occurs at low elevations in Alaska [1]. In boreal locations, global climate change is apparently resulting in upward elevational and latitudinal expansions of red fruit bearberry and other treeline species [79,86].

Climate: Red fruit bearberry occurs in areas with cold temperate [60], boreal [62], and arctic [89] climates. It is rated moderately tolerant [30] to intolerant [90] of drought, with very high winter hardiness [30].

Red fruit bearberry pioneers on gravel floodplains (review by [90]) and other bare substrates in primary succession. It colonizes bare mineral soil in tundra and taiga sites in Alaska [13]. Red fruit bearberry colonized bare, unstable dunelands along the Meade River near Barrow, but was not dominant on stable dunes [63]. However, eightpetal mountain-avens and red fruit bearberry formed a prostrate shrub community on stable dunes along the Atigun River of Alaska's North Slope [88].

Flooding disturbance may favor red fruit bearberry. On the Mackenzie Delta, red fruit bearberry cover apparently increased following spring ice breakup in 1982. The plant community, a white spruce/mountain alder-red fruit bearberry association, experiences flooding approximately once a decade. Red fruit bearberry had 10% cover and 100% frequency 4 years after flooding; its preflood abundance was not described [61]. In a russet buffaloberry-diamondleaf willow-prickly rose (Salix pulchra-Rosa acicularis) floodplain community in the central Alaskan Range, red fruit bearberry occurred on open sites in the mostly dense shrubfield. The area, on the Riley Creek floodplain, was in primary and secondary succession. The lower floodplain was scoured by an ice jam in December 1995, and several centimeters of sand were deposited during flooding and spring ice breakup in 1996. Areas left bare by heavy ice scouring, and therefore forced back to primary succession, were colonized by alpine snow lichen (Stereocaulon alpinum). The area with red fruit bearberry also supported kinnikinnick and common juniper (Juniperus communis) [54]. Cooccurrence of common juniper, which does not sprout, suggests that the floodplain area with red fruit bearberry was only lightly scoured and in early secondary succession. On upland sites that were not scoured or flooded recently, red fruit bearberry occurred in the understory of an open balsam poplar-white spruce stand that apparently established after a fire 71 years prior to the study [54].

As a species associated with treeline, red fruit bearberry often grows on the edges of receding glaciers in early primary succession. In a study of succession after glacial scouring in the northern Rocky Mountains, Heusser [35] found forbs generally colonized the scoured area, followed by low shrubs. Red fruit bearberry and eightpetal mountain-avens often dominated the low shrub stage. Shrubs and tree seedlings established on recessional moraines 10 to 60 years after glacial diminution; typically, these species include willows, bog birch, and spruces. The final stage was mature spruce forest, which developed around 100 years after spruce seedling establishment. On Mt Robson in British Columbia, red fruit bearberry followed the forbs northern sweetvetch (Hedsarium boreal subsp. mackenzie) and eightpetal mountain-avens after recession of Robson Glacier, codominating the low shrub stage with willows. At 12,972 feet (3,954 m), Mt Robson is the highest mountain in the Canadian Rocky Mountains, and Robson Glacier is the largest glacier on the mountain [82,83].

Red fruit bearberry persists on Mt Robson in mature (135-year-old) Engelmann spruce communities [35,85]. In a chronosequence study of primary succession on recessional moraines of the Robson Glacier, Blundon and Dale [9] found red fruit bearberry dominated the 3rd and last phase of successional development. A timeline for this development was not given.

Red fruit bearberry also occurs on disturbed sites in secondary succession. Canopy closure takes about 100 years on northern spruce ecosystems [41,52,53]. As of 2008, the only successional studies conducted in spruce forests with red fruit bearberry were short-term studies spanning no more than 10 years [19,34,93], so the ability of red fruit bearberry to persist in later stages of succession is unknown.

A year after blading, red fruit bearberry established from surviving "rootstalks" on a bare bulldozer track in the Mackenzie Delta [8]. In a study of succession 48 years following construction of the CANOL Pipeline in the Northwest Territories, red fruit bearberry grew in vehicle tracks, although it was at least twice as frequent on undisturbed plots compared to plots in vehicle tracks. Red fruit bearberry was not found on plots in borrow pits [31]. Red fruit bearberry dominated bulldozer lines 2 and 3 years following bulldozer blading in the Mackenzie Delta, recolonizing from intact rhizomes below the bulldozer line. On bulldozer lines in a littletree willow (Salix arbusculoides) community, red fruit bearberry cover was greater on bulldozed edges than on bulldozed line centers or control plots 2 years after blading. Where construction ran through a nearby white spruce/mountain alder community, red fruit bearberry approximated predisturbance cover 3 years after blading [34].

Few studies had been conducted on red fruit bearberry's response to logging as of 2008. In the short term, logging treatments in an open white spruce/thinleaf alder/splendid feather moss (Alnus incana subsp. tenuifolia/Hylocomium splendens) community slightly reduced red fruit bearberry abundance on Willow Island near Fairbanks, Alaska [19]:

Red fruit bearberry showed no change in cover 10 years after tree harvest or fire compared to an untreated control in a white spruce-paper birch-quaking aspen forest near Fairbanks, Alaska. Red fruit bearberry had 5% cover on clearcut, shelterwood, burned, and undisturbed control plots at postlogging year 10 [93].

FIRE ECOLOGY

• FIRE ECOLOGY OR ADAPTATIONS
• POSTFIRE REGENERATION STRATEGY

Fire regimes: The boreal spruce, tundra, and alpine communities in which red fruit bearberry grows generally experience long intervals between fires. Red fruit bearberry is most common in early postfire succession within these communities (see Plant Response to Fire).

Northern conifer ecosystems: Fires in spruce forests with red fruit bearberry generally occur more than 100 years apart, although shorter fire-return intervals also occur. Boreal black spruce forests have fire-return intervals ranging from about 50 to 100 years [41,53]. A black spruce-jack pine forest in northern boreal Quebec, for example, experienced fire at intervals of 47 to 270 years [52]. Northern spruce forests experience a combination of crown and ground fires [41,53]. Fires in spruce taiga may last for months, burning thousands to millions of acres [53].

White spruce forests of Kluane National Park, Yukon, have 150- to 400-year fire-return intervals. Mean fire-return interval increases with increasing latitude, from 133 years in the southern end of the Park, to 164 years in the middle of the Park, and 234 years in the northern end of the Park [32]. Driscoll and others [17] reported a return interval of 140+ years for fires in hybrid spruce (Picea glauca × P. engelmannii) forests of central British Columbia.

Western conifer ecosystems: As of 2008, studies on red fruit bearberry's postfire occurrence in coniferous forests in western North America were lacking, so it is difficult to project what role fire plays in red fruit bearberry abundance in those forests. Red fruit bearberry grows in white spruce forests of Wyoming and Engelmann spruce forests of British Columbia, which have relatively long fire-free intervals. Arno [3] estimated fire-return intervals for fir-spruce (Abies-Picea spp.) forests of the northern Rocky Mountains at 150+ years. Intervals of 100 to 250 years between fires are characteristic of Rocky Mountain lodgepole pine in the northern Rockies [4,5]; however, mean fire intervals may be as short as 20 to 50 years in small stands [3].

As of 2008, no information was available on fire regimes in shrub tundra and alpine ecosystems with red fruit bearberry. Tundra fires are usually small and stand replacing. In Alaska and western Canada, tundra fires typically burn only 2.5 to 25 acres (1-10 ha). Some tundra fires, however, have burned up to 247,000 acres (100,000 ha) [7]. Alpine ecosystems with red fruit bearberry probably burn infrequently due to sparse fuels.

The following table provides fire regime information that may be relevant to red fruit bearberry. Find further 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".

FIRE EFFECTS

• IMMEDIATE FIRE EFFECT ON PLANT
• DISCUSSION AND QUALIFICATION OF FIRE EFFECT
• PLANT RESPONSE TO FIRE
• DISCUSSION AND QUALIFICATION OF PLANT RESPONSE
• FIRE MANAGEMENT CONSIDERATIONS

Red fruit bearberry's sprouting response is best documented in spruce ecosystems, where limited studies suggest that it may gain cover slowly after fire. Origin of postfire sprouts (rhizomes and/or stolons) had not been determined as of 2008. A white birch-black spruce-tundra ecotone on the Mackenzie Delta was burned under prescription on 3 July 1973. Red fruit bearberry sprouts were observed on study plots on 1 August 1973, following observations of earlier-sprouting cloudberry (Rubus chamaemorus) and bluejoint grass (Calamagrostis canadensis) plants [91]. Red fruit bearberry also sprouted after the stand-replacing Porcupine Wildfire in northeastern Alaska, gaining prefire coverage slowly. Its cover on 23-year-old burn plots was less than half that of that on control plots in adjacent, unburned black spruce forest [24]:

In spruce forests of the Mackenzie Valley, red fruit bearberry had low cover in both young and old burns [70].

Red fruit bearberry recovered more quickly from fire on a black spruce-tundra ecotone site than on a tundra site [49].

Prefire brush clearing resulted in slow red fruit bearberry recovery compared to sites that were undisturbed before fire. On a subarctic black spruce woodland in the Northwest Territories, red fruit bearberry frequency was inventoried 8 years before a wildfire and in postfire year 3. Postfire red fruit bearberry frequency was least on right-of-way sites that were cleared 10 years before the wildfire [58].

Prescribed burning may have promoted red fruit bearberry seedling establishment in the Kenai Mountains of Alaska. Burning was conducted on 13 May 1983 in a Lutz's spruce/Barclay's willow (Picea × lutzii/Salix barclayi) forest to promote growth of moose browse. Red fruit bearberry was not present on transects before burning and had 1% cover in postfire year 15. The author found that postfire cover of browse species was generally greatest on sites where palatable shrubs were present before fire, while sites dominated by bluejoint grass had lowest cover of browse species after fire [11].

A wildfire on the Seward Peninsula of Alaska apparently had little effect on red fruit bearberry. The 1977 wildfire burned through previously-sampled plots in tussock-shrub tundra dominated by sheathed cottonsedge, Bigelow's sedge (Carex bigelowii), bog birch, and bog blueberry (Vaccinium uliginosum). Red fruit bearberry frequency was about 10% higher in postfire year 24 than before the fire, but its cover remained low and little changed [65].

Similarly, red fruit bearberry's frequency increased with time since fire, while its cover decreased, on study sites in interior Alaska [80]:

DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:
No additional information is available on this topic.

FIRE MANAGEMENT CONSIDERATIONS:
Sparse data make it impossible to recommend fire management practices for red fruit bearberry. Since red fruit bearberry is a low-growing, early-successional plant (see Successional Status), it is likely that red fruit bearberry declines with canopy closure after fire in coniferous forests and tundra shrublands. Further studies are needed on the fire ecology of red fruit bearberry.

MANAGEMENT CONSIDERATIONS

• IMPORTANCE TO WILDLIFE AND LIVESTOCK
• VALUE FOR REHABILITATION OF DISTURBED SITES
• OTHER USES
• OTHER MANAGEMENT CONSIDERATIONS

Palatability/nutritional value: Hardy [30] rated red fruit bearberry browse as moderately palatable and moderately tolerant of browsing pressure.

Cover value: Red fruit bearberry is an "especially important" cover and forage species for meadow voles in Fort Churchill, Manitoba [25].

Woodland caribou in the Mackenzie and Selwyn mountains of Yukon and the Northwest Territories use snowfields within arctic mountain-avens-red fruit bearberry tundra cushion plant communities as relief habitat to escape insect harassment [42].

Red fruit bearberry plants can be obtained from stem cuttings. Propagation from seed may be a "lengthy and difficult process" [90]. In an experimental restoration in the Northwest Territories, red fruit bearberry failed to establish from locally-collected seed broadcast in a trench [21,55]. However, shrub establishment was monitored for only 1 year after sowing, so it is possible that the seed was still dormant and established in later years [55]. Red fruit bearberry-dominated sites along the Alaskan Highway in Yukon are rated "relatively insensitive" to "highly sensitive" to disturbance, depending on soil type. Red fruit bearberry vegetation types on sand or gravel are rated relatively insensitive, while those on peat or other organic soils are rated highly sensitive [76].

Arctostaphylos rubra: REFERENCES

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