Vaccinium Membranaceum Research Articles

Effects of bear endozoochory on germination and dispersal of huckleberry in the Canadian Rocky Mountains.

Berries are a staple of bear diets during late summer and fall in the southern Rocky Mountains, enabling bears to build up fat reserves and prepare to enter torpor during winter. In turn, bears can benefit fruiting shrubs through dispersal of their seeds. Bears are highly mobile species and seed passage through their guts (endozoochory) can influence seed germination in three ways: deinhibition (removal of germination inhibiting compounds), scarification (mechanical or chemical alteration) and fertilization (enhancement of germination from increased nutrients). We conducted a germination experiment to assess the ways each mechanism of bear endozoochory affects germination success of huckleberry (Vaccinium membranaceum.) in the southern Canadian Rocky Mountains. The potential for bears to act as long-distance seed dispersers was also investigated, using a combination of available literature on bear gut retention times and movement data of 74 GPS radio-collared grizzly bears. Deinhibition had a positive significant impact (28.5% germination for the Seeds from Berry treatment compared to 0.2% for Whole Berry at 60 days), while scarification and fertilization did not have detectable positive effects on huckleberry germination success. These results suggest that the removing germination-inhibiting compounds in berry pulp is the primary mechanism through which endozoochory can increase germination in huckleberry seed. We estimated that 50% of the seeds defecated by bears in the region are dispersed 1.1 km away from feeding places (and up to 7 km). The surfaces covered by the seed shadow was up to 149.6 km2, demonstrating that bears can act as effective vectors of seeds over long distances. Endozoochory bolsters the germination success of seeds from fruiting shrubs, and enables seeds to spread to new locations using bears as dispersal agents. Development, resource extraction, and climate change may disrupt the beneficial relationship between bears and huckleberries, where huckleberries help bears gain fat, and bears help spread huckleberry seeds-a process that may become increasingly important as climate change alters habitats.

Downed woody debris microsite facilitation for planted black huckleberry seedling regeneration

Black huckleberry (Vaccinium membranaceum)—an economically, ecologically, and culturally important shrub across the Pacific and Inland Northwest—is experiencing widespread declines in suitable habitat because of fire suppression and climate change. We tested the role of experimentally placed downed woody debris (DWD) in mitigating unsuitable habitat conditions through creating favorable abiotic microsites and promoting black huckleberry seedling survival. We planted 1‐year‐old black huckleberry seedlings at four distances (0, 0.25, 0.5, and 1.5 m) from DWD, on the north and south aspects of east‐to‐west‐oriented DWD, at three study sites in Northern Idaho, United States. Over one growing season (May to September), we measured seedling survival, chlorophyll fluorescence (Fv/fm), soil surface temperature (SST), and soil volumetric water content (VWC) monthly. Only 21% of seedlings survived the entire season, but survival on the north DWD aspect (28.3%) was twice that of the south (14.2%). Additionally, survival at the nearest distances (0 and 0.25 m; 29%) was double that of farther distances (0.5 and 1.5 m; 13.6%) for both DWD aspects. The north aspect and nearest distances were also associated with the highest Fv/fm, lowest SST, and highest VWC, confirming expected abiotic characteristics of the DWD‐associated microsite. The distinct spatial and directional effects highlight a facet of DWD microsites, which can improve best practices for microsites during restoration. We demonstrate that DWD‐facilitated microsites can be a pivotal restoration tool to ameliorate climate extremes and enhance shrub recruitment into more durable life stages.

First Report and Genome Resource of Monilinia vaccinii-corymbosi, causal agent of Mummy Berry Disease of Black Huckleberry (Vaccinium membranaceum).

Monilinia vacccinii-corymbosi (phylum Ascomycota, family Sclerotiniaceae) causes fruit disease 'mummy berry' on berry crops and responsible for yield losses and quality of fruits. We reported mummy berry disease of black huckleberry (Vaccinium membranaceum) first time in British Columbia, Canada. We have performed sequencing and genome assembly of M. vacccinii-corymbosi from infected fruits of huckleberry. The resulting genome was 33.8 Mbp in size and consisted of 2,437 scaffolds with an N50 of 33,816 bp. To our best knowledge, this is the first report of resource announcement of whole genome sequence of mummy berry pathogen (M. vacccinii-corymbosi) infecting black huckleberry. The genome resource will be valuable for future studies to understand the genomic structure of pathogen, and mechanisms associated with black huckleberry-M. vacccinii-corymbosi interactions.

Berries and bullets: influence of food and mortality risk on grizzly bears in British Columbia

AbstractThe influence of bottom‐up food resources and top‐down mortality risk underlies the demographic trajectory of wildlife populations. For species of conservation concern, understanding the factors driving population dynamics is crucial to effective management and, ultimately, conservation. In southeastern British Columbia, Canada, populations of the mostly omnivorous grizzly bear (Ursus arctos) are fragmented into a mosaic of small isolated or larger partially connected sub‐populations. They obtain most of their energy from vegetative resources that are also influenced by human activities. Roads and associated motorized human access shape availability of food resources but also displace bears and facilitate human‐caused mortality. Effective grizzly bear management requires an understanding of the relationship between habitat quality and mortality risk. We integrated analyses of bottom‐up and top‐down demographic parameters to understand and inform a comprehensive and efficient management paradigm across the region. Black huckleberry (Vaccinium membranaceum) is the key high‐energy food for grizzly bears in much of southeastern British Columbia. Little is known about where and why huckleberries grow into patches that are useful for grizzly bears (i.e., densely clustered fruiting shrubs that provide efficient access to high energy food) and how forage supply and mortality risk influence population vital rates. By following 43 grizzly bears tracked with global positioning system (GPS) collars (57 bear years) in a 14,236‐km2 focal area spanning the Selkirk and Purcell mountain ranges, we developed a model to identify huckleberry patches from grizzly bear use data. Over 2 years we visited 512 sites used by bears, identifying more than 300 huckleberry patches. We used boosted regression tree modeling associating geophysical, ecological, soil, climate, and topographical variables with huckleberry patches. We integrated this modeled food layer depicting an important pre‐hibernation resource, into broader bottom‐up and top‐down analyses. In addition to berries, we examined bottom‐up variables indexing vegetative productivity that were previously found to be predictive of bear use (e.g., alpine, canopy cover, greenness, riparian). We also examined top‐down variables including road presence, road density, distance‐to‐road, secure habitat (defined as 500 m away from a road open to vehicular access), highways, human development, and terrain ruggedness. We evaluated the relationship of these variables to female habitat selection, fitness, and population density, testing the predictability and interrelatedness of covariates relative to bottom‐up and top‐down influences. We estimated resource selection functions with 20,293 GPS telemetry locations collected over 10 years from 20 female grizzly bears. We modeled fitness using logistic regression of spatially explicit reproductive data derived from genetically identified family pedigrees consisting of a mother, father, and offspring. Data included 33 mothers and 72 offspring (1–8 offspring per female). We estimated density through spatial capture‐recapture analysis of 126 grizzly bears detected with hair‐sampled DNA 287 times between 1998 and 2005. In all 3 analyses (habitat selection, fitness, and density), huckleberry patches were the most influential bottom‐up factor and secure habitat was the most consistent top‐down variable (road density was similarly predictive). All of the best supported models contained bottom‐up and top‐down variables except the male density model, which only contained a top‐down variable (secure habitat). These results suggest that both bottom‐up and top‐down forces drive several population processes of grizzly bears in the region, especially for females. We found that 38% of huckleberry patches (235 km2) predicted by the top model were in non‐secure habitat and that these patches were associated with lower fitness and density relative to those in secure habitat. Grizzly bear density was 2.6 times higher in habitat with road densities <0.6 km/km2, supporting the use of this road density target for management. The models predict that applying motorized access controls to backcountry areas with huckleberry patches would increase grizzly bear abundance by 23% on average across the region and 125% in the lowest density portion of the study area (Yahk). Managing both bottom‐up and top‐down influences is necessary to best mitigate the expanding human footprint, which is affecting many carnivore species worldwide. We provide evidence that bottom‐up forces were more influential for female habitat selection, fitness, and density than top‐down effects. We also uncovered a critical pattern in the magnitude of top‐down and bottom‐up influences on behavioral (habitat selection) and demographic (population density and fitness) responses. We show that the relative influence of top‐down influences on habitat selection and fitness are relatively weak compared to bottom‐up influences, whereas top‐down pressures exert much stronger limiting forces on population density. Forming conservation decisions around behavioral responses alone may misdirect actions and have limited benefits to populations. This insight can facilitate more effective decision‐making for grizzly bear conservation. Our findings highlight the importance of considering both bottom‐up and top‐down influences, suggesting cautious interpretation of habitat selection models for any species. A comprehensive examination with population‐level metrics such as density, vital rates, and fitness may be needed for effective management.

Polyphenolic profiles of a variety of wild berries from the Pacific Northwest region of North America

Polyphenols have been extensively profiled and quantified in commercially grown berries, but similar information is sparsely available for wild berries. Because polyphenolic contents are inherently associated with berries health benefits, determining phenolic profiles is an important step for strategizing potential uses by the industry and for health and nutrition outcomes. Here, we profiled phenolic compounds in wild berries commonly encountered and harvested in the Pacific Northwest region of North America. Huckleberries (Vaccinium membranaceum) of varying phenotypes were found to be comparable to related blueberries in terms of general phenolic classes composition. However, all huckleberries exhibited markedly high levels of cyanidins, and delphinidins or peonidins were also higher in specific phenotypes. Wild black elderberries (Sambucus nigra spp. Canadensis) were found to have remarkably high phenolic, especially anthocyanins, in line with reports from cultivated elderberries. Saskatoon serviceberries (Amelanchier alnifolia) were found to exhibit high polyphenol content, but with a less diverse profile dominated by quercetin. The most intriguing berry may be the Oregon grape (Mahonia Aquifolium) being the only one exhibiting more than one g of polyphenols per 100 g; as well as a remarkably even distribution of the different anthocyanin classes. All colored wild berries were found to have at minimum comparable total phenolic contents when compared to cultivated and other wild berries, suggesting they should exhibit comparable human health benefits such as antioxidant and metabolic syndrome preventative potential described for these other berries. Overall, our data represents a valuable resource to explore the potential to valorize wild berry species for their specific phenolic profiles and predicted nutritional and health properties. With repeated phenolic profiling to better understand the impact of the environment, the wild berries described here hold promises both as food ingredient applications as well as valuable complement for healthy dietary patterns.

Occurrence of Mummy Berry Associated with Huckleberry (Vaccinium membranaceum) Caused by Monilinia spp. in Oregon.

In this Short Communication we describe the occurrence of mummy berry associated with huckleberry (Vaccinium membranaceum) caused by Monilinia spp. in Oregon. To our knowledge, this is the first report of a Monilinia spp. associated with mummy berry of huckleberry in Oregon. Sequence data from our specimens reveal the closest identity was Monilinia vaccinii-corymbosi, a pathogen of commercial blueberry (Vaccinium corymbosum). This may be a new species of Monilinia, not previously reported on huckleberry, and further investigation is needed. Of specific importance, the huckleberry holds cultural importance as a sacred First Food of the Confederated Tribes of the Umatilla Indian Reservation and other Pacific Northwest tribes. Although plant pathogen management in natural landscapes presents unique challenges, we will work with tribal authorities to determine whether cultural management techniques may mitigate yield loss due to Monilinia spp.

Using DNA Barcoding Methods to Identify Wild Huckleberry, Vaccinium membranaceum, as a Classroom Project

In 2019 the Biology 100 class of Wenatchee Valley College at Omak (WVCO) worked on a DNA barcoding project with Tabitha Graves’s huckleberry research project for bear habitat in Glacier National Park, Montana. Students isolated DNA from huckleberry leaf samples from the National Park. They then ran a PCR with an rbcL primer pair to target the rubisco gene in plant chloroplasts. The PCR product was sequenced by a private company, Genewiz, and the DNA sequence was analyzed through DNA Subway. Twelve student groups, one or two students per group, isolated DNA from huckleberry leaf samples that was sequenced and analyzed. Twelve samples were determined to be of the genus Vaccinium. One of the twelve samples distinguished between the five species of huckleberry, identified the sample as Vaccinium membranaceum, and was published in GenBank. They showed that DNA barcoding can be used successfully to aid in the identification of this species of huckleberry. There were many student outcomes, including hands-on skills with the tools of DNA technology, contributing to a real-world project, and analyzing data for DNA sequence matches. This is a great lab exercise to use for AP biology classes, two-year community college biology classes, and four-year college biology classes at the 100 to 200 level.

Climate change shifts in habitat suitability and phenology of huckleberry (Vaccinium membranaceum)

Climate change is altering the suitable habitat and phenology of plant species around the world, with cascading effects on people and animals reliant upon those plant species as food sources. Huckleberry (Vaccinium membranaceum) is one of these important food-producing plant species that grows in the Pacific Northwest of North America. Here, we modelled how the range and phenology of huckleberry may change as the climate changes. To address this question, we first utilized citizen scientist observations, long-term plot data, and gridded climate data to identify climate variables that best predicted the current bioclimatic niche and the timing of flowering and fruit ripening of huckleberry. We then used multi-model future climate projections for 2 time periods (2041–2070 and 2071–2100) and 2 greenhouse gas emissions scenarios (RCP 4.5 and RCP 8.5) to predict how the range and the timing of flowering and fruiting would change. The modelled bioclimatic niche for the current time period was a good match for our observations, with the model predicting a high probability of occurrence where the species was observed (AUC = 0.88). Suitable habitat for huckleberry was predicted to shrink by 5–40% across the northwestern USA by the end of the 21st century, and this reduction in predicted probability of occurrence was greatest at lower elevations, across drier portions of the current range of the species, and under the higher emissions scenario. Suitable habitat was predicted to expand at higher altitudes (>3,050 m) and in more northern locations in British Columbia by 5–60% by the end of the 21st century. To predict how future phenological dates might shift, we developed thermal sum models for flowering and fruiting under current climate conditions and then used those models to predict how these events would change based on climate predictions. Our phenology models suggested flowering would advance 23–50 days (mean 35 days) and fruiting would advance 24–52 days (mean 36 days) by the end of the 21st century under the RCP 8.5 scenario; greater advances in phenology were shown over more northerly and higher altitude regions. These large shifts in potential range and phenology could greatly alter trophic relationships and the timing and location of traditional harvests in the future.

Traditional knowledge of fire use by the Confederated Tribes of Warm Springs in the eastside Cascades of Oregon

We examined traditional knowledge of fire use by the Ichishikin (Sahaptin), Kitsht Wasco (Wasco), and Numu (Northern Paiute) peoples (now Confederated Tribes of Warm Springs, CTWS) in the eastside Cascades of Oregon to generate insights for restoring conifer forest landscapes and enhancing culturally-valued resources. We examined qualitative and geospatial data derived from oral history interviews, participatory GIS focus groups, archival records, and historical forest surveys to characterize cultural fire regimes (CFRs) –an element of historical fire regimes– of moist mixed conifer (MMC), dry mixed conifer (DMC), and shrub-grassland (SG) zones. Our ethnohistorical evidence indicated a pronounced cultural fire regime in the MMC zone, but not in the two drier zones. The CFR of the MMC zone was characterized by frequent (few-year recurrence), low-severity burns distributed in a shifting pattern. This regime helped to maintain forest openings created by previous ignitions, resulting from lightning or possibly human-set, that had burned large areas. The CFR was influenced by the CTWS traditional knowledge system, which consisted of four elements: fire use and associated resource tending practices, tribal ecological principles, the seasonal round (the migratory pattern to fulfill resource needs), and culture. Thinleaf huckleberry (Vaccinium membranaceum), a cultural keystone species, occurs primarily in the MMC zone and was a principle focus of traditional fire use of the CTWS peoples. Fire was deployed to maintain shrub productivity and site access for harvesting. Cessation of fire use by ∼1940 has caused a decline in huckleberry productivity throughout much of the historical harvest zone. Our findings about CFR scale show how a nested, multi-level framework (patch- and landscape-levels) may be employed to reintroduce fire and thereby promote forest restoration and enhance culturally-valued resources. Our findings also highlight the utility of engaging the communities that hold traditional knowledge in the forest management and planning process.

Mapping a keystone shrub species, huckleberry (Vaccinium membranaceum), using seasonal colour change in the Rocky Mountains

ABSTRACTBlack huckleberries (Vaccinium membranaceum) provide a critical food resource to many wildlife species, including apex omnivores such as the grizzly bear (Ursus arctos), and play an important socioeconomic role for many communities in western North America, especially indigenous peoples. Remote sensing imagery offers the potential for accurate landscape-level mapping of huckleberries because the shrub changes colour seasonally. We developed two methods, for local and regional scales, to map a shrub species using leaf seasonal colour change from remote sensing imagery. We assessed accuracy with ground-based vegetation surveys. The high-resolution supervised random forest classification from one-meter resolution National Agricultural Imagery Program (NAIP) imagery achieved an overall accuracy of 75.31% (kappa = 0.26). The approach using multi-temporal 30-meter Landsat imagery similarly had an overall accuracy of 79.19% (kappa = .31). We found underprediction error was related to higher forest cover and a lack of visible colour change on the ground in some plots. Where forest cover was low, both models performed better. In areas with <10% forest cover, the high-resolution classification achieved an accuracy of 80.73% (kappa = 0.48), while the Landsat model had an accuracy of 82.55% (kappa = 0.47). Based on the fine-scale predictions, we found that 94% of huckleberry shrubs identified in our study area of Glacier National Park, Montana, USA are over 100 meters from human recreation trails. This information could be combined with productivity and phenology information to estimate the timing and availability of food resources for wildlife and to provide managers with a tool to identify and manage huckleberries. The development of the multi-temporal Landsat models sets the stage for assessment of impacts of disturbance at regional scales on this ecologically, culturally, and economically important shrub species. Our approach to map huckleberries is straightforward, efficient and accessible to wildlife and environmental managers and researchers in diverse fields.

Do remnant retention patches and forest edges increase grizzly bear food supply?

Grizzly bears should benefit from forest harvesting strategies that emulate patterns of natural disturbance, such as wildfire, presumably because of increased foraging opportunities associated with open and edge habitats. Several studies have linked early seral habitats associated with natural and anthropogenic disturbances to increased food supply for grizzly bear. However, few have quantitatively evaluated whether food supply is higher along forest edges, particularly edges created by different forest harvesting strategies such as structure retention. Here we tested whether grizzly bear food supply was: 1) more common/abundant along forest harvest (cutblock) edges; 2) similar between undisturbed forest matrix (uncut) undisturbed forest remnants (i.e., retention patches) that were situated within forest harvests; and 3) similar in terms of responses relative to retention and forest harvest edges. To address these questions, we measured the distribution and abundance of plant-based food resources used by grizzly bears along edge distance gradients associated with to three forest treatments (cutblock, uncut forest, and retention patch) in Alberta, Canada. We then used information theory to compare models and evaluate support for factors. We found that blueberry (Vaccinium membranaceum, V. myrtilloides, and V. vitis-idaea.) shrubs, which are known to be sensitive to mechanical damage and soil disturbance from harvest and post-harvest site preparation, were more common/abundant near young ( ≤ 20 years) forest edges. Conversely, raspberry (Rubus idaeus) shrubs, horsetail (Equisetum arvense), and cow parsnip (Heracleum lanatum), which are known to be positively associated with soil disturbance, were generally more common/abundant away from forest edges. Blueberry, fruit production was highest at forest harvest edges and lowest in older cutblocks, as well as retention patches, which we showed contained fewer lodgepole pine (Pinus contorta) trees and more deciduous species. These results support the contention that understory disturbance, environmental conditions (e.g. light availability), and forest tree species composition could explain our research findings. As part of stand-level prescriptions, we recommend that forest managers consider maintaining uncut forest adjacent to cutblocks for up to 20 years post-harvest, and create more and smaller retention patches to increase the amount of forest edge. We also recommend that criteria be developed for selecting the spatial location of forest edges and retention patches such that blueberry shrubs are common/abundant in the undisturbed forest. This research demonstrated that forest harvesting strategies can increase food supply for grizzly bears and thus support recovery efforts of this provincially threatened species.

Leaf-level physiology in four subalpine plants in tephra-impacted forests during drought

Ecological impacts of climate change in the Pacific Northwest may hinge on acclimation to drier summers, highlighting the importance of plant physiological studies in forests. Evaluating dominant forest plant species under old-growth and managed forest conditions is similarly important as timber harvest might change microclimates and alter drought effects on plants. We examined water potential and gas exchange rates of four dominant plant species in understories of subalpine forests of the Pacific Northwest region of the United States during 2015 — a year with drought conditions representative of future climate projections. We examined two conifer species (Abies amabilis Douglas ex J. Forbes and Tsuga heterophylla (Raf.) Sarg.) and two huckleberry species (Vaccinium membranaceum Douglas ex Torr. and Vaccinium ovalifolium Sm.) in old-growth and formerly clear-cut forests at two elevations. Contrary to expectations, we found no evidence of hydraulic stress, and there were no significant differences between old-growth and clear-cut stands, consistent with an edaphic buffering effect in this volcanic landscape. Variation in stem elongation rates among years also indicated the lack of a strong drought response in 2015. Water potential, photosynthesis, and stomatal conductance varied among species and among elevations. In combination, our results help constrain expected physiological activity of understory species in subalpine forests and emphasize the importance of the edaphic context (e.g., tephra deposits) in framing expectations for the responses to drought.

Airborne laser scanning for modelling understory shrub abundance and productivity

Fiber production is no longer the sole objective of forest management, with increasing importance placed on other goods and services, such as maintaining habitat quality and stand successional development. Evaluating habitat quality and understory composition across complex landscapes remains a challenge for forest and wildlife managers, but is essential for ensuring the stability of vulnerable species. In this study we investigate whether forest stand structure, as measured by airborne laser scanning (ALS), can be used to predict the abundance and fruit production (fruit count) for Canada buffaloberry (Shepherdia canadensis), huckleberry (Vaccinium membranaceum), and saskatoon (Amelanchier alnifolia) shrubs in southwest Alberta, Canada. We combine ALS, climate, and terrain data to build random forest models of species abundance and fruit productivity, trained on data from 322 field plots. ALS data was processed into a suite of stand structure variables, under the hypothesis that models incorporating stand structure will be more powerful than models without for describing understory shrub abundance and reproduction (fruit productivity). ALS data improved model fit for saskatoon and huckleberry abundance models, with total explained variance (r2) ranging from 37.6 to 59.4%. Inclusion of ALS data improved explained variance between 0% and 16%, suggesting that saskatoon and huckleberry in particular were associated with overstory vegetation structure. Despite the importance of ALS in further improving explanation of shrub abundance and fruit production, terrain factors were the dominant factor affecting regional and local variation in species abundance and fruit production.

The Effects of Disturbance History on Ground-Layer Plant Community Composition in British Columbia

Plant communities are sensitive to perturbations and may display alternative recovery pathways depending on disturbance history. In sub-boreal lodgepole pine forests of central interior British Columbia, Canada, fire and logging are two widespread landscape disturbances that overlap in many regions. We asked whether cumulative, short-interval disturbance from logging and fire resulted in different ground-layer plant communities than resulted from fire alone. Using field-collected data, we compared the taxonomic composition and functional traits of 3-year old plant communities that were either harvested 6-to-13 years prior, or not harvested prior to being burned in a large stand-replacing fire. The taxonomic composition diverged between the two treatments, driven primarily by differences in a few key indicator species such as Petasites frigidus and Vaccinium membranaceum. Analysis of individual species’ morphological traits indicated that only a few species vary in size in relation to disturbance history. Our data suggest that a history of forest harvest leaves a subtle footprint on post-fire ground-layer plant communities at early stages of succession.

Wildlife habitat enhancements for grizzly bears: Survival rates of planted fruiting shrubs in forest harvests

Productive grizzly bear foraging habitats are lost as the prevalence of natural forest openings declines. We assessed the effectiveness of using wildlife habitat enhancements to increase food supply for grizzly bears in recent forest harvests by conducting planting trials of containerized shrub seedlings for three important late-season grizzly bear foods (fruiting shrubs): Shepherdia canadensis (Canada buffaloberry), Vaccinium membranaceum (mountain huckleberry), and Amelanchier alnifolia (saskatoon). We monitored seedling survival over two growing seasons and considered the effects of soil nutrient amendments, exclosures, initial seedling condition, and environmental factors (elevation and terrain). A. alnifolia had the highest survival rate, although it may not be as effective in the long term due to being preferred ungulate winter browse. Soil nutrient amendments reduced survival rates of all three species, perhaps due to competition with grasses, whereas exclosures increased survival rates. Survival rates across an elevation gradient for S. canadensis and A. alnifolia were inversely related to local occupancy rates, demonstrating that knowledge of their realized niche space is not consistent with early establishment rates of seedlings. As the amount of natural forest openings declines, wildlife habitat enhancements in disturbed sites with open canopies, including forest harvests, have the potential to locally increase late-season food supply for grizzly bears.

Some mechanisms underlying variation in vital rates of grizzly bears on a multiple use landscape

Understanding factors that govern the abundance of organisms is fundamental to the science of ecology and important for conservation and management of species. I used temporal and spatial comparisons to test the influence of human industrial activity, huckleberry (Vaccinium membranaceum) productivity, and population density on grizzly bear (Ursus arctos) vital rates and population trends over a 32-year period. Survival rates of adult and subadult males were 0.84 and 0.78, respectively, and lower than those of adult (0.93) or subadult females (0.96). Of the 31 bears that died while radio-collared, 26 (84%) were killed by people. Of those killed by people, 11 (35%) were legally killed by hunters and 84% were deaths that occurred <120 m from a road. In the first decade of study (1979–1988) when salvage logging and gas exploration was intensive, bear density was relatively low, and huckleberry production was generally good, the population increased (λ = 1.074) with high survival rates of cubs (0.84) and yearlings (0.86) plus a high reproductive rate of 0.374. During the second decade (1989–1998) when there was little industrial activity and huckleberry production remained good, the population continued to grow (λ ≈ 1.06–1.08) because survival of all age classes remained high, but the reproductive rate declined to 0.257. Bear density reached its maximum (55.6 bears/1,000 km2 excluding independent males) at the start of the third decade. During the third decade (1999–2010), there was little industrial activity, but huckleberry production declined dramatically and often completely failed. During the third decade the population declined (λ ≈ 0.955–0.980) as the reproductive rate dropped to 0.192 because of small litters (1.82), extended interbirth intervals (2.93, 3.44, and 4.22 years in decades 1, 2, and 3, respectively) and increased age of primiparity (6.60, 7.09, and 10.46 years in decades 1, 2, and 3, respectively). Adult female survival also declined likely because more females were without offspring and thus vulnerable to hunting. The best model predicting if a parous female would have a small (0 or 1 cub) or large (2 or 3 cub) litter when not encumbered with offspring the previous mating season included both huckleberry abundance the previous year and female bear density. Population inventories during the third decade had approximately twice as many bears detected per DNA hair trap set in the portion of the valley where there had been rapid industrial development, grizzly bear hunting, and large huckleberry fields than in an adjacent portion of the valley that was protected from industry and hunting but with no major huckleberry fields. The abundance of huckleberries growing in mountains above most human activity permitted this population to expand in spite of the industrial development. The population was primarily regulated by the interaction of bear density and the density-independent production of huckleberries, their major summer-fall energy food. © 2015 The Wildlife Society.

Propagation of Vaccinium membranaceum and V. myrtilloides: Seeds, Hardwood Stem, and Rhizome Cutting Methods

Propagation trials were completed using seeds, hardwood stem cuttings, and rhizome cuttings from black huckleberry ( Vaccinium membranaceum Douglas ex Torr. [Ericaceae]) and velvetleaf blueberry ( V. myrtilloides Michx. [Ericaceae]) growing in central British Columbia, Canada. Seed germination success rates for V. membranaceum were 26.0% in 2006, 4.7% in 2007, and 66.0% in 2008, compared with 14.7% in 2006, 13.0% in 2007, and 28.5% in 2008 for V. myrtilloides . Germination rates for seeds sown directly after extraction from fresh berries were similar to those that had been air-dried for 48 h, and those stored for 1 y. Germination rates did vary significantly between Vaccinium species and among different years. Hardwood stem cuttings of both V. membranaceum and V. myrtilloides , taken in February, had low rooting rates (2.5%). Rooting hormone formulation, rooting substrate, and bottom heat failed to influence rooting success. Rhizome cuttings of V. myrtilloides had an 85% success rate, compared to 70% for V. membranaceum . Bottom heat significantly reduced the success rate of rhizome cuttings, whereas rooting substrate had no significant influence. Mass production of either V. membranaceum or V. myrtilloides plants was easiest by using seedlings grown from seeds; however, if clonal plants are desired (or a short production time required), rhizome cuttings might be the best option, rather than hardwood stem cuttings.

Sensitivity of berry productivity to climatic variation in the Cabinet–Yaak grizzly bear recovery zone, Northwest United States, 1989–2010

AbstractBerry‐producing shrubs are culturally, economically, and ecologically important for both people and animals in the Pacific Northwest of the United States. We examined huckleberry (Vaccinium membranaceum) and serviceberry (Amelanchier alnifolia) productivity across the Cabinet–Yaak grizzly bear recovery zone in Northern Idaho and Western Montana. An index of annual berry productivity was measured at field plots from 1989 to 2010. Temperature, precipitation, and snow indices were derived from nearby Snowpack Telemetry (SNOTEL) stations. Huckleberry production was highest during cool springs with high July diurnal temperature ranges. April–June growing‐degree days and July temperature range explain 70% of the inter‐annual variability in huckleberry productivity. Serviceberry production was correlated with maximum snow‐water equivalent and April–June growing‐degree days, which explained 86% of the variance in annual serviceberry production. These models show potential to forecast annual berry production and to anticipate potential bear–human interactions. Further development of models is essential to better predict the potential changes in important wildlife resources in the context of climate change. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

The Effect of Consumers and Mutualists of Vaccinium membranaceum at Mount St. Helens: Dependence on Successional Context

In contrast to secondary succession, studies of terrestrial primary succession largely ignore the role of biotic interactions, other than plant facilitation and competition, despite the expectation that simplified interaction webs and propagule-dependent demographics may amplify the effects of consumers and mutualists. We investigated whether successional context determined the impact of consumers and mutualists by quantifying their effects on reproduction by the shrub Vaccinium membranaceum in primary and secondary successional sites at Mount St. Helens (Washington, USA), and used simulations to explore the effects of these interactions on colonization. Species interactions differed substantially between sites, and the combined effect of consumers and mutualists was much more strongly negative for primary successional plants. Because greater local control of propagule pressure is expected to increase successional rates, we evaluated the role of dispersal in the context of these interactions. Our simulations showed that even a small local seed source greatly increases population growth rates, thereby balancing strong consumer pressure. The prevalence of strong negative interactions in the primary successional site is a reminder that successional communities will not exhibit the distribution of interaction strengths characteristic of stable communities, and suggests the potential utility of modeling succession as the consequence of interaction strengths.

Community structure of ericoid mycorrhizas and root-associated fungi of Vaccinium membranaceum across an elevation gradient in the Canadian Rocky Mountains

Abstract The ecological plasticity of Vaccinium membranaceum (Ericaceae) to grow from valley bottoms to alpine habitats allowed us to test if fungal community structure varies along an elevation gradient in east-central British Columbia. Using the shrub as an independent variable, and plant and soil features along the gradient to model a changing climate, communities of root-associated fungi were investigated. The colonized roots from 40 individuals were examined using culture-dependent sequencing and ARISA (automated ribosomal intergenic spacer analysis). Our results demonstrated that high elevation fungal communities, characterised by Rhizoscyphus ericae , differ from lower elevation communities, where Phialocephala fortinii was the most frequently isolated fungus. Co-occurrence analysis indicated that, overall, fungi tended to occur together more often than would be expected by chance. At the scale of the individual host plant, facilitation may play a more important role than competition in shaping fungal communities in these ecosystems.