scholarly journals Modeling the demography of species providing extended parental care: A capture–recapture multievent model with a case study on polar bears ( Ursus maritimus )

2021 ◽  
Vol 11 (7) ◽  
pp. 3380-3392
Author(s):  
Sarah Cubaynes ◽  
Jon Aars ◽  
Nigel G. Yoccoz ◽  
Roger Pradel ◽  
Øystein Wiig ◽  
...  
Keyword(s):  
Parental Care ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Capture Recapture ◽  
Extended Parental Care

scholarly journals Modeling the demography of species providing extended parental care: A capture-recapture multievent model with a case study on Polar Bears (Ursus maritimus)

2019 ◽  
Author(s):  
Sarah Cubaynes ◽  
Jon Aars ◽  
Nigel G. Yoccoz ◽  
Roger Pradel ◽  
Øystein Wiig ◽  
...  
Keyword(s):  
Parental Care ◽  
Litter Size ◽  
Ursus Maritimus ◽  
Reproductive History ◽  
Demographic Parameters ◽  
Capture Recapture ◽  
Breeding Probability ◽  
Extended Parental Care

AbstractIn species providing extended parental care, one or both parents care for altricial young over a period including more than one breeding season. We expect large parental investment and long-term dependency within family units to cause high variability in life trajectories among individuals with complex consequences at the population level. So far, models for estimating demographic parameters in free-ranging animal populations mostly ignore extended parental care, thereby limiting our understanding of its consequences on parents and offspring life histories.We designed a capture-recapture multi-event model for studying the demography of species providing extended parental care. It handles statistical multiple-year dependency among individual demographic parameters grouped within family units, variable litter size, and uncertainty on the timing at offspring independence. It allows to evaluate trade-offs among demographic parameters, the influence of past reproductive history on the caring parent survival status, breeding probability and litter size probability, while accounting for imperfect detection of family units. We assess the model performances using simulated data, and illustrate its use with a long-term dataset collected on the Svalbard polar bears (Ursus maritimus).Our model performed well in terms of bias and mean square error and in estimating demographic parameters in all simulated scenarios, both when offspring departure probability from the family unit occurred at a constant rate or varied during the field season depending on the date of capture. For the polar bear case study, we provide estimates of adult and dependent offspring survival rates, breeding probability and litter size probability. Results showed that the outcome of the previous reproduction influenced breeding probability.Overall, our results show the importance of accounting for i) the multiple-year statistical dependency within family units, ii) uncertainty on the timing at offspring independence, and iii) past reproductive history of the caring parent. If ignored, estimates obtained for breeding probability, litter size, and survival can be biased. This is of interest in terms of conservation because species providing extended parental care are often long-living mammals vulnerable or threatened with extinction.

Relationships Between Plasma Levels of Organochlorines, Retinol and Thyroid Hormones from Polar Bears (Ursus maritimus) at Svalbard

2001 ◽  
Vol 62 (4) ◽  
pp. 227-241 ◽  
Author(s):  
Janneche Utne Skaare ◽  
Aksel Bernhoft ◽  
Øystein Wiig ◽  
Kaare R. Norum ◽  
Egil Haug ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Plasma Levels ◽  
Ursus Maritimus ◽  
Polar Bears

Mixed methods to assess the use of rare illicit psychoactive substances: a case study

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Eric Janssen ◽  
Mike Vuolo ◽  
Clément Gérome ◽  
Agnès Cadet-Taïrou
Keyword(s):  
Crack Cocaine ◽  
Mixed Method Research ◽  
Psychoactive Substances ◽  
Ethnographic Studies ◽  
Field Evidence ◽  
Capture Recapture ◽  
Hard To Reach Populations ◽  
Quantitative Results ◽  
Cocaine Users

Abstract This article presents original mixed method research to describe the use of rare illicit psychoactive substances, with special emphasis on crack cocaine in France. We first introduce a unique monitoring system committed to the observation of hard-to-reach populations. Qualitative findings rely, among others, on perennial ethnographic studies and field professionals’ knowledge to provide guidance to estimate the number of crack cocaine users. We then rely on a set of multilevel capture-recapture estimators, a statistical procedure to indirectly estimate the size of elusive populations. Since prior field evidence suggests an increasing diversity in crack cocaine users’ profiles, we provide a measure of heterogeneity to assess which estimator better fits the data. The calculated estimates are then critically reviewed and debated in light of the previously gathered information. Our results uncover both individual and institutional heterogeneity and suggest that the spread of crack cocaine in France initiated earlier than originally thought. Our case study underlines the need for field-driven assessments to put quantitative results into perspective, a necessary step to tailor efficient health policy responses.

Performance of helicopter-based biopsy darting of polar bears (Ursus maritimus) on the spring sea ice

2021 ◽  
Vol 67 (6) ◽  
Author(s):  
Thomas S. Jung ◽  
Michael J. Suitor ◽  
Steve Baryluk
Keyword(s):  
Sea Ice ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Spring Sea Ice

New insights into dietary management of polar bears ( Ursus maritimus ) and brown bears ( U. arctos )

Zoo Biology ◽  
2021 ◽  
Author(s):  
Charles T. Robbins ◽  
Troy N. Tollefson ◽  
Karyn D. Rode ◽  
Joy A. Erlenbach ◽  
Amanda J. Ardente
Keyword(s):  
Ursus Maritimus ◽  
Dietary Management ◽  
Polar Bears ◽  
Brown Bears

scholarly journals Polar bears (Ursus maritimus) mating during late June on the pack ice of northern Svalbard, Norway

2015 ◽  
Vol 34 (1) ◽  
pp. 25786 ◽  
Author(s):  
Thomas G. Smith ◽  
Jon Aars
Keyword(s):  
Ursus Maritimus ◽  
Polar Bears ◽  
Pack Ice

scholarly journals Three decades (1983–2010) of contaminant trends in East Greenland polar bears (Ursus maritimus). Part 2: Brominated flame retardants

2013 ◽  
Vol 59 ◽  
pp. 494-500 ◽  
Author(s):  
Rune Dietz ◽  
Frank F. Rigét ◽  
Christian Sonne ◽  
Erik W. Born ◽  
Thea Bechshøft ◽  
...  
Keyword(s):  
Flame Retardants ◽  
Brominated Flame Retardants ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
East Greenland

The breeding habitat of the ringed seal (Phoca hispida). The birth lair and associated structures

1975 ◽  
Vol 53 (9) ◽  
pp. 1297-1305 ◽  
Author(s):  
Thomas G. Smith ◽  
Ian Stirling
Keyword(s):  
Ursus Maritimus ◽  
Ringed Seal ◽  
Breeding Habitat ◽  
Polar Bears ◽  
Alopex Lagopus ◽  
Phoca Hispida ◽  
Arctic Foxes ◽  
Different Types ◽  
Amundsen Gulf

The subnivean lairs of the ringed seal (Phoca hispida) were studied in the Amundsen Gulf and Prince Albert Sound areas from 1971 through 1974. The structure of several different types of lairs are described. The existence of a birth-lair complex consisting of several closely adjacent lairs appears likely. The spacial distribution of lairs and lair types found on refrozen leads and in pressure ridges is described. Lairs were more abundant in inshore ice than in offshore ice. The function of subnivean lairs appears to be to provide thermal shelter, especially for neonate seals, and protection from predation by arctic foxes (Alopex lagopus) and polar bears (Ursus maritimus).

Preliminary results of fasting on the kinetics of organochlorines in polar bears (Ursus maritimus)

1995 ◽  
Vol 160-161 ◽  
pp. 465-472 ◽  
Author(s):  
S.C. Polischuk ◽  
R.J. Letcher ◽  
R.J. Norstrom ◽  
M.A. Ramsay
Keyword(s):  
Ursus Maritimus ◽  
Polar Bears ◽  
Preliminary Results ◽  
Kinetics Of

Persistent organic pollutants and penile bone mineral density in East Greenland and Canadian polar bears (Ursus maritimus) during 1996–2015

2018 ◽  
Vol 114 ◽  
pp. 212-218 ◽  
Author(s):  
Tobias Daugaard-Petersen ◽  
Rikke Langebæk ◽  
Frank F. Rigét ◽  
Markus Dyck ◽  
Robert J. Letcher ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Organic Pollutants ◽  
Bone Mineral ◽  
Persistent Organic Pollutants ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Mineral Density ◽  
East Greenland
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