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

Larsen, Terrence A.; Nielsen, Scott E.; Cranston, Jerome; Stenhouse, Gordon B.

doi:10.1016/j.foreco.2018.11.031

Cited by 16 publications

(9 citation statements)

References 81 publications

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“…Grizzly bear food resources tend to be on edges, which are typically areas with low canopy cover (Roever et al 2008). Furthermore, young (≤20 yr) forest edges have been found to facilitate an increase in grizzly bear food supply (Nielsen et al 2004c, Larsen et al 2019. Females have Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Food resource availability included variables that characterize forest conditions and represent the limitation, distribution, abundance, and quality of foods, as well as the availability and distributions of foods related to disturbance features. Many bear foods are more abundant where the forest canopy is open or near forest edges (Nielsen et al 2004c, Larsen et al 2019), and bears using regenerating forests with a variety of age classes have shown improved body condition compared to those using older, conifer‐dominated forests (Boulanger et al 2013). Therefore, we used raster data on crown closure, percent conifer, and land cover—originally derived from Landsat 5 and 7 ETM imagery and a digital elevation model (DEM)—to represent food resource availability (McDermid 2005).…”

Section: Methodsmentioning

confidence: 99%

“…Grizzly bear habitat in Alberta has become highly fragmented due to resource extraction activities (i.e., forestry, oil and gas exploration, mining, and agriculture), widespread road networks, and human recreational activities (Berland et al 2008, Proctor et al 2012). Anthropogenic disturbed areas can cause an increase in seasonal food availability (Nielsen et al 2016, Kearney et al 2019, Larsen et al 2019), such as increases in the abundance and occurrence of berries and fruits associated with more clearings and forest opening, which grizzly bears have been found to select and can result in an increase in human contact and reduced bear survival rates (McLellan and Hovey 2001, Nielsen et al 2004a, 2004b, 2004c, Berland et al 2008). Furthermore, this multi‐use landscape has facilitated genetically fragmented sub‐populations (Proctor et al 2005, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…It has also been shown that HCC values in female grizzly bears, and to a lower degree in males, were reduced in areas highly impacted by human disturbance (Bourbonnais et al 2013). The authors suggest that decreased HCC values may be related to seasonal increases in food availability and distribution in areas with anthropogenic disturbance (Nielsen et al 2016, Kearney et al 2019, Larsen et al 2019).…”

Section: Introductionmentioning

confidence: 99%

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Population‐level monitoring of stress in grizzly bears between 2004 and 2014

et al. 2020

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Grizzly bears (Ursus arctos) in west‐central Alberta occupy an increasingly human‐dominated landscape. Natural resource extraction activities are hypothesized to increase stress in animals that reside in such changing landscapes by influencing habitat and resource availability. Our study aimed to determine whether stress, represented by hair cortisol concentration (HCC), was associated with variables related to landscape conditions in a population that increased by 7% annually from 2004 to 2014. Hair samples (n = 157) were collected using barbwire hair snags placed throughout the Yellowhead bear management area in Alberta, Canada. Candidate models were developed a priori representing hypotheses related to biologically and ecologically plausible relationships between HCC and landscape variables. Generalized linear model analysis with landscape attributes representing anthropogenic disturbance, food resource availability, and terrain conditions was used to determine potential drivers of HCC. We found support (ΔAICc ≤ 2.00) for three models that included variables from each hypothesis. Anthropogenic variables had the greatest impact on HCC; increasing oil and gas well‐site density resulted in reduced HCC, while increasing distance to coal mines resulted in elevated HCC. Hair cortisol concentration also increased as forest crown closure became more variable, while HCC decreased as the soil wetness (represented by compound topographic index) increased. Some forms of anthropogenic disturbance have been linked to increased food availability for this species. Therefore, we suggest that changes in landscape conditions from 2004 to 2014 may have indirectly increased food abundance and ultimately resulted in a reduction in HCC at a population level during this time period. Measuring HCC provides a non‐invasive and important monitoring strategy to assess the impact of environmental change on residing species and should be considered in landscape management decisions.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Population‐level monitoring of stress in grizzly bears between 2004 and 2014

et al. 2020

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“…Elevation, solar insolation, topographic wetness, and landcover influence vegetation productivity and food availability and have been linked to grizzly bear habitat selection [23–25]. Bears also select for both natural and anthropogenic edges [26–27], related to an abundance of important habitat resources. Previous work has shown negative and positive selection for roads, due to both high food productivity and high risk [28–32].…”

Section: Introductionmentioning

confidence: 99%

Grizzly bear response to fine spatial and temporal scale spring snow cover in Western Alberta

et al. 2019

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Snow dynamics influence seasonal behaviors of wildlife, such as denning patterns and habitat selection related to the availability of food resources. Under a changing climate, characteristics of the temporal and spatial patterns of snow are predicted to change, and as a result, there is a need to better understand how species interact with snow dynamics. This study examines grizzly bear ( Ursus arctos ) spring habitat selection and use across western Alberta, Canada. Made possible by newly available fine-scale snow cover data, this research tests a hypothesis that grizzly bears select for locations with less snow cover and areas where snow melts sooner during spring (den emergence to May 31 st ). Using Integrated Step Selection Analysis, a series of models were built to examine whether snow cover information such as fractional snow covered area and date of snow melt improved models constructed based on previous knowledge of grizzly bear selection during the spring. Comparing four different models fit to 62 individual bear-years, we found that the inclusion of fractional snow covered area improved model fit 60% of the time based on Akaike Information Criterion tallies. Probability of use was then used to evaluate grizzly bear habitat use in response to snow and environmental attributes, including fractional snow covered area, date since snow melt, elevation, and distance to road. Results indicate grizzly bears select for lower elevation, snow-free locations during spring, which has important implications for management of threatened grizzly bear populations in consideration of changing climatic conditions. This study is an example of how fine spatial and temporal scale remote sensing data can be used to improve our understanding of wildlife habitat selection and use in relation to key environmental attributes.

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