Monitoring of grizzly bear population trends and demography using DNA mark–recapture methods in the Owikeno Lake area of British Columbia

2004 ◽  
Vol 82 (8) ◽  
pp. 1267-1277 ◽  
Author(s):  
J Boulanger ◽  
S Himmer ◽  
C Swan
Keyword(s):  
British Columbia ◽  
Spatial Variation ◽  
Joint Modeling ◽  
Population Trend ◽  
Population Trends ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Lake Area ◽  
Population Demography ◽  
Mark Recapture

We used DNA sampling and mark–recapture modeling to estimate population trend(s), population size, and the demographic response of a coastal British Columbia grizzly bear population (Ursus arctos L., 1758) to low salmon escapement levels from 1998 to 2002. We contrasted the demography of three sampling areas in response to temporal and spatial variation in salmon availability. Population trend (λ) estimates suggested that salmon availability was too low in the first 2 years of the study to sustain grizzly bear populations. One of the sampling areas exhibited higher levels of salmon availability in later years of the study, leading to increased rates of addition. Apparent survival rates increased in all areas potentially as a result of increased salmon availability. Joint interpretation of λ and superpopulation estimates allowed for the assessment of whether salmon availability levels were high enough to sustain current population sizes of grizzly bears on salmon streams. This study illustrates how joint modeling of separate sampling areas can be used to assess spatial variation in population demography and population trends, as well as increase precision of estimates for individual sampling areas. It also illustrates how DNA mark–recapture can be used as a methodology to explore the effects of changes in environmental conditions on population demography and population trend of grizzly bears or of other wildlife species.

scholarly journals Estimating unrecorded human-caused mortalities of grizzly bears in the Flathead Valley, British Columbia, Canada

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5781
Author(s):  
Bruce N. McLellan ◽  
Garth Mowat ◽  
Clayton T. Lamb
Keyword(s):  
British Columbia ◽  
Ursus Arctos ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Considerable Uncertainty ◽  
The Government ◽  
Reporting Rates ◽  
Gravel Road

Managing the number of grizzly bear (Ursus arctos) mortalities to a sustainable level is fundamental to bear conservation. All known grizzly bear deaths are recorded by management agencies but the number of human-caused grizzly bear deaths that are not recorded is generally unknown, causing considerable uncertainty in the total number of mortalities. Here, we compare the number of bears killed legally by hunters to the number killed by people for all other reasons, for bears wearing functioning radiocollars and for uncollared bears recorded in the British Columbia (BC) government mortality database for the Flathead Valley in southeast BC. Between 1980 and 2016, permitted hunters killed 10 collared bears and 12 (9 known, 3 suspected) were killed by people for other reasons. This ratio differed (p < 0.0001) from the uncollared bears in the government database where 71 were killed by hunters while only 10 were killed for other reasons. We estimate that 88% (95% CI; 67–96%) of the human-caused mortalities that were not by permitted hunters were unreported. The study area may have low reporting rates because it is >40 km on a gravel road from a Conservation Officer office, so reporting is difficult and there are no human residences so there is little concern of a neighbor contacting an officer. Our results are likely indicative of other places that are road-accessed but far from settlements. We discuss the implications of sampling individuals for collaring and the possible implications of wearing a collar on the animal’s fate.

Major components of grizzly bear diet across North America

2006 ◽  
Vol 84 (3) ◽  
pp. 473-489 ◽  
Author(s):  
Garth Mowat ◽  
Douglas C Heard
Keyword(s):  
British Columbia ◽  
North America ◽  
Rangifer Tarandus ◽  
Ursus Arctos ◽  
Nitrogen Isotope ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Carbon And Nitrogen ◽  
Skull Size ◽  
Meat Diet

We measured stable carbon and nitrogen isotope ratios in guard hair of 81 populations of grizzly bears (Ursus arctos L., 1758) across North America and used mixing models to assign diet fractions of salmon, meat derived from terrestrial sources, kokanee (Oncorhynchus nerka (Walbaum in Artedi, 1792)), and plants. In addition, we examined the relationship between skull size and diet of bears killed by people in British Columbia. The majority of carbon and nitrogen assimilated by most coastal grizzly bear populations was derived from salmon, while interior populations usually derived a much smaller fraction of their nutrients from salmon, even in areas with relatively large salmon runs. Terrestrial prey was a large part of the diet where ungulates were abundant, with the highest fractions observed in the central Arctic, where caribou (Rangifer tarandus (L., 1758)) were very abundant. Bears in some boreal areas, where moose (Alces alces (L., 1758)) were abundant, also ate a lot of meat. Bears in dryer areas with low snowfall tended to have relatively high meat diet fractions, presumably because ungulates are more abundant in such environments. Kokanee were an important food in central British Columbia. In areas where meat was more than about a third of the diet, males and females had similar meat diet fractions, but where meat was a smaller portion of the diet, males usually had higher meat diet fractions than females. Females reached 95% of their average adult skull length by 5 years of age, while males took 8 years. Skull width of male grizzly bears increased throughout life, while this trend was slight in females. Skull size increased with the amount of salmon in the diet, but the influence of terrestrial meat on size was inconclusive. We suggest that the amount of salmon in the diet is functionally related to fitness in grizzly bears.

scholarly journals Divergent population trends following the cessation of legal grizzly bear hunting in southwestern British Columbia, Canada

2019 ◽  
Vol 233 ◽  
pp. 247-254
Author(s):  
Michelle L. McLellan ◽  
Bruce N. McLellan ◽  
Rahel Sollmann ◽  
Clayton T. Lamb ◽  
Clayton D. Apps ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Trends ◽  
Grizzly Bear

Use of naturally occurring mercury to determine the importance of cutthroat trout to Yellowstone grizzly bears

2004 ◽  
Vol 82 (3) ◽  
pp. 493-501 ◽  
Author(s):  
Laura A Felicetti ◽  
Charles C Schwartz ◽  
Robert O Rye ◽  
Kerry A Gunther ◽  
James G Crock ◽  
...  
Keyword(s):  
Ursus Arctos ◽  
Food Resource ◽  
Cutthroat Trout ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Lake Area ◽  
Yellowstone Lake ◽  
Virtual Absence ◽  
Hair Mercury ◽  
Naturally Occurring

Spawning cutthroat trout (Oncorhynchus clarki (Richardson, 1836)) are a potentially important food resource for grizzly bears (Ursus arctos horribilis Ord, 1815) in the Greater Yellowstone Ecosystem. We developed a method to estimate the amount of cutthroat trout ingested by grizzly bears living in the Yellowstone Lake area. The method utilized (i) the relatively high, naturally occurring concentration of mercury in Yellowstone Lake cutthroat trout (508 ± 93 ppb) and its virtual absence in all other bear foods ([Formula: see text]6 ppb), (ii) hair snares to remotely collect hair from bears visiting spawning cutthroat trout streams between 1997 and 2000, (iii) DNA analyses to identify the individual and sex of grizzly bears leaving a hair sample, (iv) feeding trials with captive bears to develop relationships between fish and mercury intake and hair mercury concentrations, and (v) mercury analyses of hair collected from wild bears to estimate the amount of trout consumed by each bear. Male grizzly bears consumed an average of 5 times more trout/kg bear than did female grizzly bears. Estimated cutthroat trout intake per year by the grizzly bear population was only a small fraction of that estimated by previous investigators, and males consumed 92% of all trout ingested by grizzly bears.

scholarly journals Grizzly bear toe amputation due to seasonal overlap with furbearer trapping in southeast British Columbia

2021 ◽  
Author(s):  
Clayton Lamb ◽  
Laura Smit ◽  
Luke Vander Vennen ◽  
Garth Mowat ◽  
Michael Proctor ◽  
...  
Keyword(s):  
British Columbia ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Active Season ◽  
The North ◽  
New Information ◽  
American Model ◽  
Innovative Solutions ◽  
Wildlife Populations ◽  
Management Approaches

Science and adaptive management form crucial components of the North American model of wildlife management. Under this model, wildlife managers are encouraged to update management approaches when new information arises whose implementation could improve the stewardship and viability of wildlife populations and the welfare of animals. Here we detail a troubling observation of multiple grizzly bear toe amputations in southeast British Columbia and assemble evidence to inform immediate action to remedy the issue. During the capture of 59 grizzly bears in southeast British Columbia, we noticed that four individuals (~7%) were missing some or all their toes on one of their front feet. The wounds were all well healed and linear in nature. Further opportunistic record collection revealed that this pattern of missing toes occurred beyond our study area, and that furbearer traps were responsible for toe loss. We documented a problematic seasonal overlap between the active season for grizzly bears and the fall trapping seasons for small furbearers with body grip traps and for wolves with leghold traps. Instead of opening these trapping seasons on or prior to November 1, when more than 50% of bears are still active, we recommend delaying the start of these seasons until December 1, when most bears have denned. Innovative solutions, such as narrowing trap entrances to exclude bear feet while still allowing entrance of target furbearers, have the potential to minimize accidental capture of bears but the effectiveness of these approaches is unknown. Solutions that do not involve season changes will require monitoring of efficacy and compliance to ensure success.

Landscape permeability for grizzly bear movements in Washington and southwestern British Columbia

Ursus ◽  
2004 ◽  
Vol 15 (1) ◽  
pp. 90-103 ◽  
Author(s):  
Peter H. Singleton ◽  
William L. Gaines ◽  
John F. Lehmkuhl
Keyword(s):  
British Columbia ◽  
Grizzly Bear ◽  
Landscape Permeability

A grizzly bear from the Middle Wisconsin of Woodbridge, Ontario

1976 ◽  
Vol 13 (2) ◽  
pp. 341-347 ◽  
Author(s):  
Charles S. Churcher ◽  
Alan V. Morgan
Keyword(s):  
Ursus Arctos ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Bone Fragment ◽  
Mammuthus Primigenius ◽  
Ursus Arctos Horribilis ◽  
Before And After ◽  
Lake Simcoe ◽  
Left Humerus ◽  
Woolly Mammoth

The distal end of the left humerus of a grizzly bear, Ursus arctos, has been recovered from above the Early Wisconsin Sunnybrook Till at Woodbridge, Ontario, from the same horizon that previously has yielded remains of the woolly mammoth, Mammuthus primigenius. The age of these specimens is estimated at 40 000–50 000 years BP, within the mid-Wisconsin, Port Talbot Interstadial. The only other recognized Canadian record of a grizzly bear east of Manitoba is from a gravel sequence at Barrie, near Lake Simcoe, Ontario, dated from a bone fragment to 11 700 ± 250 years BP. A specimen recovered in Toronto in 1913 from an Early Wisconsin horizon is also considered to represent the grizzly. Bears of the grizzly type, Ursus arctos-horribilis were present in Ontario before and after the Early and Late Wisconsin ice advances.

Mark-recapture models

1984 ◽  
Vol 16 (1) ◽  
pp. 24-24
Author(s):  
P. D. M. Macdonald
Keyword(s):  
British Columbia ◽  
Biological System ◽  
Probabilistic Model ◽  
General Model ◽  
Mark Recapture ◽  
Salmon Smolt

The interpretation of mark-recapture data depends on a probabilistic model for the biological system. The assumptions of the general model must be verified against what is known about the particular system. This talk considers the application of markrecapture methods to the estimation of salmon smolt migrations from Babine Lake, British Columbia.

Rare earth element concentrations in Quaternary volcanic rocks of southwestern British Columbia

1984 ◽  
Vol 21 (6) ◽  
pp. 731-736 ◽  
Author(s):  
Nathan L. Green ◽  
Paul Henderson
Keyword(s):  
British Columbia ◽  
Earth Element ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Lake Area ◽  
Calc Alkaline ◽  
Lower Light ◽  
The Individual ◽  
High Level ◽  
Ree Patterns

A suite of hy-normative hawaiites, ne-normative mugearite, and calc-alkaline andesitic rocks from the Garibaldi Lake area exhibits fractionated, slightly concave-upward REE patterns (CeN/YbN = 4.5–15), heavy REE contents about 5–10 times the chondritic abundances, and no Eu anomalies. It is unlikely that the REE patterns provide information concerning partial melting conditions beneath southwestern British Columbia because they have probably been modified substantially by upper crustal processes including crustal contamination and (or) crystal fractionation. The REE contents of the Garibaldi Lake lavas are not incompatible with previous interpretations that (1) the hawaiites have undergone considerable fractionation of olivine, plagioclase, and clinopyroxene; and (2) the individual andesitic suites were derived from separate batches of chemically distinct magma that evolved along different high-level crystallization trends. In general, however, the andesites are characterized by lower light REE contents than the basaltic andesites. These differences in LREE abundances may reflect different amounts of LREE-rich accessory phases, such as apatite, sphene, or allanite, assimilated from the underlying quartz diorites.

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