Integrated Population Modeling Provides the First Empirical Estimates of Vital Rates and Abundance for Polar Bears in the Chukchi Sea.
Sci Rep
; 8(1): 16780, 2018 11 14.
Article
em En
| MEDLINE
| ID: mdl-30429493
ABSTRACT
Large carnivores are imperiled globally, and characteristics making them vulnerable to extinction (e.g., low densities and expansive ranges) also make it difficult to estimate demographic parameters needed for management. Here we develop an integrated population model to analyze capture-recapture, radiotelemetry, and count data for the Chukchi Sea subpopulation of polar bears (Ursus maritimus), 2008-2016. Our model addressed several challenges in capture-recapture studies for polar bears by including a multievent structure reflecting location and life history states, while accommodating state uncertainty. Female breeding probability was 0.83 (95% credible interval [CRI] = 0.71-0.90), with litter sizes of 2.18 (95% CRI = 1.71-2.82) for age-zero and 1.61 (95% CRI = 1.46-1.80) for age-one cubs. Total adult survival was 0.90 (95% CRI = 0.86-0.92) for females and 0.89 (95% CRI = 0.83-0.93) for males. Spring on-ice densities west of Alaska were 0.0030 bears/km2 (95% CRI = 0.0016-0.0060), similar to 1980s-era density estimates although methodological differences complicate comparison. Abundance of the Chukchi Sea subpopulation, derived by extrapolating density from the study area using a spatially-explicit habitat metric, was 2,937 bears (95% CRI = 1,552-5,944). Our findings are consistent with other lines of evidence suggesting the Chukchi Sea subpopulation has been productive in recent years, although it is uncertain how long this will continue given sea-ice loss due to climate change.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Reprodução
/
Ursidae
/
Taxa de Sobrevida
Tipo de estudo:
Prognostic_studies
Limite:
Animals
País/Região como assunto:
America do norte
Idioma:
En
Revista:
Sci Rep
Ano de publicação:
2018
Tipo de documento:
Article