Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana
We estimated grizzly bear (Ursus arctos) population vital rates and trend for the Northern Continental Divide Ecosystem (NCDE), Montana, between 2004 and 2009 by following radio-collared females and observing their fate and reproductive performance. Our estimates of dependent cub and yearling surviv...
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DigitalCommons@University of Nebraska - Lincoln
2012
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ftunivnebraskali:oai:digitalcommons.unl.edu:usgsstaffpub-1562 2023-11-12T04:27:44+01:00 Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana Mace, Richard D. Carney, Daniel W. Chilton-Radandt, Tonya Courville, Stacy A. Haroldson, Mark A. Harris, Richard B. Jonkel, James Mclellan, Bruce Madel, Michael Manley, Timothy Schwartz, Charles Servheen, Christopher Stenhouse, Gordon Waller, John S. Wenum, Erik 2012-01-01T08:00:00Z application/pdf https://digitalcommons.unl.edu/usgsstaffpub/553 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1562/viewcontent/Mace_JWM_2012_Grizzly_Bear_Population_Vital_Rates.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/usgsstaffpub/553 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1562/viewcontent/Mace_JWM_2012_Grizzly_Bear_Population_Vital_Rates.pdf USGS Staff -- Published Research grizzly bear lambda Montana mortality population trend reproduction survival Ursus arctos text 2012 ftunivnebraskali 2023-10-30T11:00:00Z We estimated grizzly bear (Ursus arctos) population vital rates and trend for the Northern Continental Divide Ecosystem (NCDE), Montana, between 2004 and 2009 by following radio-collared females and observing their fate and reproductive performance. Our estimates of dependent cub and yearling survival were 0.612 (95% CI = 0.300–0.818) and 0.682 (95% CI = 0.258–0.898). Our estimates of subadult and adult female survival were 0.852 (95% CI = 0.628–0.951) and 0.952 (95% CI = 0.892– 0.980). From visual observations, we estimated a mean litter size of 2.00 cubs/litter. Accounting for cub mortality prior to the first observations of litters in spring, our adjusted mean litter size was 2.27 cubs/litter. We estimated the probabilities of females transitioning from one reproductive state to another between years. Using the stable state probability of 0.322 (95% CI = 0.262–0.382) for females with cub litters, our adjusted fecundity estimate (mx) was 0.367 (95% CI = 0.273–0.461). Using our derived rates, we estimated that the population grew at a mean annual rate of approximately 3% (λ = 1.0306, 95% CI = 0.928–1.102), and 71.5% of 10,000 Monte Carlo simulations produced estimates of λ > 1.0. Our results indicate an increasing population trend of grizzly bears in the NCDE. Coupled with concurrent studies of population size, we estimate that over 1,000 grizzly bears reside in and adjacent to this recovery area. We suggest that monitoring of population trend and other vital rates using radioed females be continued. Text Ursus arctos University of Nebraska-Lincoln: DigitalCommons@UNL Lambda ENVELOPE(-62.983,-62.983,-64.300,-64.300) |
institution |
Open Polar |
collection |
University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
grizzly bear lambda Montana mortality population trend reproduction survival Ursus arctos |
spellingShingle |
grizzly bear lambda Montana mortality population trend reproduction survival Ursus arctos Mace, Richard D. Carney, Daniel W. Chilton-Radandt, Tonya Courville, Stacy A. Haroldson, Mark A. Harris, Richard B. Jonkel, James Mclellan, Bruce Madel, Michael Manley, Timothy Schwartz, Charles Servheen, Christopher Stenhouse, Gordon Waller, John S. Wenum, Erik Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana |
topic_facet |
grizzly bear lambda Montana mortality population trend reproduction survival Ursus arctos |
description |
We estimated grizzly bear (Ursus arctos) population vital rates and trend for the Northern Continental Divide Ecosystem (NCDE), Montana, between 2004 and 2009 by following radio-collared females and observing their fate and reproductive performance. Our estimates of dependent cub and yearling survival were 0.612 (95% CI = 0.300–0.818) and 0.682 (95% CI = 0.258–0.898). Our estimates of subadult and adult female survival were 0.852 (95% CI = 0.628–0.951) and 0.952 (95% CI = 0.892– 0.980). From visual observations, we estimated a mean litter size of 2.00 cubs/litter. Accounting for cub mortality prior to the first observations of litters in spring, our adjusted mean litter size was 2.27 cubs/litter. We estimated the probabilities of females transitioning from one reproductive state to another between years. Using the stable state probability of 0.322 (95% CI = 0.262–0.382) for females with cub litters, our adjusted fecundity estimate (mx) was 0.367 (95% CI = 0.273–0.461). Using our derived rates, we estimated that the population grew at a mean annual rate of approximately 3% (λ = 1.0306, 95% CI = 0.928–1.102), and 71.5% of 10,000 Monte Carlo simulations produced estimates of λ > 1.0. Our results indicate an increasing population trend of grizzly bears in the NCDE. Coupled with concurrent studies of population size, we estimate that over 1,000 grizzly bears reside in and adjacent to this recovery area. We suggest that monitoring of population trend and other vital rates using radioed females be continued. |
format |
Text |
author |
Mace, Richard D. Carney, Daniel W. Chilton-Radandt, Tonya Courville, Stacy A. Haroldson, Mark A. Harris, Richard B. Jonkel, James Mclellan, Bruce Madel, Michael Manley, Timothy Schwartz, Charles Servheen, Christopher Stenhouse, Gordon Waller, John S. Wenum, Erik |
author_facet |
Mace, Richard D. Carney, Daniel W. Chilton-Radandt, Tonya Courville, Stacy A. Haroldson, Mark A. Harris, Richard B. Jonkel, James Mclellan, Bruce Madel, Michael Manley, Timothy Schwartz, Charles Servheen, Christopher Stenhouse, Gordon Waller, John S. Wenum, Erik |
author_sort |
Mace, Richard D. |
title |
Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana |
title_short |
Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana |
title_full |
Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana |
title_fullStr |
Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana |
title_full_unstemmed |
Grizzly Bear Population Vital Rates and Trend in the Northern Continental Divide Ecosystem, Montana |
title_sort |
grizzly bear population vital rates and trend in the northern continental divide ecosystem, montana |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2012 |
url |
https://digitalcommons.unl.edu/usgsstaffpub/553 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1562/viewcontent/Mace_JWM_2012_Grizzly_Bear_Population_Vital_Rates.pdf |
long_lat |
ENVELOPE(-62.983,-62.983,-64.300,-64.300) |
geographic |
Lambda |
geographic_facet |
Lambda |
genre |
Ursus arctos |
genre_facet |
Ursus arctos |
op_source |
USGS Staff -- Published Research |
op_relation |
https://digitalcommons.unl.edu/usgsstaffpub/553 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1562/viewcontent/Mace_JWM_2012_Grizzly_Bear_Population_Vital_Rates.pdf |
_version_ |
1782341241764052992 |