Those Po Po Poley Bears

Discussion in 'Environment' started by Weatherman2020, May 25, 2018.

  1. Weatherman2020
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    Weatherman2020 Educating Libs Since 1978

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    The latest survey shows only one of the 13 regions in the world shows a population decline, others are stable or increasing. Inuit consider all regions stable or increasing.

    Status of Canadian polar bears updated map from Environment Canada
     
  2. BlindBoo
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    BlindBoo Gold Member

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    Hummmm, bears follow the ice. Their dinner, seals, also follow the ice. Rocket science it's not.
     
  3. Fort Fun Indiana
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    Fort Fun Indiana Gold Member

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    • Informative Informative x 1
  4. Crick
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    Crick Gold Member

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    From the IUCN, the folks that classify animal species threat levels. This indicates that one of 19 subpopulations has increased and the remaining 18 subpopulations were either stable, decreasing or unknown.

    Ursus maritimus Phipps, 1774

    Assessment Information

    Red List Category & Criteria: Vulnerable A3c ver 3.1
    Year Published: 2015
    Date Assessed: 2015-08-27
    Assessor(s): Wiig, Ø., Amstrup, S., Atwood, T., Laidre, K., Lunn, N., Obbard, M., Regehr, E. & Thiemann, G.
    Reviewer(s): Rondinini, C.
    Contributor(s): Akçakaya, H.R., Holmes, E., Reynolds, J., Stern, H., Schliebe, S. & Derocher, A.E
    Justification:
    Loss of Arctic sea ice due to climate change is the most serious threat to Polar Bears throughout their circumpolar range (Obbard et al. 2010, Stirling and Derocher 2012, USFWS 2015). We performed a data-based sensitivity analysis with respect to this threat by evaluating the potential response of the global Polar Bear population to projected sea-ice conditions. Our analyses included a comprehensive assessment of generation length (GL) for Polar Bears; development of a standardized sea-ice metric representing important habitat characteristics for the species; and population projections, over three Polar Bear generations, using computer simulation and statistical models representing alternative relationships between sea ice and Polar Bear abundance.

    Our analyses highlight the potential for large reductions in the global Polar Bear population if sea-ice loss continues, which is forecast by climate models and other studies (IPCC 2013). Our analyses also highlight the large amount of uncertainty in statistical projections of Polar Bear abundance and the sensitivity of projections to plausible alternative assumptions. Across six scenarios that projected polar bear abundance three generations forward in time using the median and 95th percentile of estimated GL, the median probability of a reduction in the mean global population size greater than 30% was approximately 0.71 (range 0.20-0.95; see Table 4 in the attached Supporting Material). The median probability of a reduction greater than 50% was approximately 0.07 (range 0-0.35), and the probability of a reduction greater than 80% was negligible. The International Union for the Conservation of Nature Red List Guidelines suggests that assessors consider nearly the full range of uncertainty in potential outcomes, and adopt a precautionary but realistic attitude toward risk tolerance (Section 3.2.3, IUCN 2014). In light of the significant probability, across scenarios, of a reduction in mean global population size greater than 30%, and the relatively low probability of a reduction greater than 50%, we conclude that Polar Bears currently warrant listing as Vulnerable under criterion A3c (IUCN 2014).

    For further information about this species, see 22823_Ursus_maritimus.pdf.
    A PDF viewer such as Adobe Reader is required.
    Previously published Red List assessments:
    • 2008 – Vulnerable (VU)
    • 2006 – Vulnerable (VU)
    • 1996 – Lower Risk/conservation dependent (LR/cd)
    • 1994 – Vulnerable (V)
    • 1990 – Vulnerable (V)
    • 1988 – Vulnerable (V)
    • 1986 – Vulnerable (V)
    • 1982 – Vulnerable (V)
    • 1965 – Less rare but believed to be threatened-requires watching
    Population
    Population: At present, 19 subpopulation units of Polar Bears are recognized by the Polar Bear Specialist Group (PBSG) of the International Union for the Conservation of Nature (Obbard et al. 2010). Genetic studies have shown that gene flow occurs among the various subpopulations (Paetkau et al. 1999, Crompton et al. 2008, Peacock et al. 2015) and there is no evidence that any of the units have been evolutionarily separated for significant periods of time. Although demographic exchange may be limited between subpopulations (Mauritzen et al. 2002, Crompton et al. 2008, Peacock et al. 2015), some demographic and genetic exchange occurs. Consequently, the Polar Bear subpopulations cannot be considered as distinct demographic units and the term “management units” may be more accurate. Ongoing reductions in the duration, distribution, and quality of sea ice due to climate change (Sahanatien and Derocher 2012) may result in different levels of genetic and demographic exchange among subpopulations in the future (Derocher et al. 2004, Molnár et al. 2010), which could lead to new metapopulation dynamics or to functionally isolated subpopulations.

    The PBSG summarized the best-available scientific information on the status of the 19 subpopulations of Polar Bears in 2014 (PBSG 2015) including an assessment of current trend (i.e., estimated change in population size over a 12-year period, centred on the time of assessment). The PBSG concluded that one subpopulation (M’Clintock Channel) has increased, six were stable (Davis Strait, Foxe Basin, Gulf of Boothia, Northern Beaufort Sea, Southern Hudson Bay, and Western Hudson Bay), three were considered to have declined (Baffin Bay, Kane Basin, and Southern Beaufort Sea) and, for the remaining nine (Arctic Basin, Barents Sea, Chukchi Sea, East Greenland, Kara Sea, Lancaster Sound, Laptev Sea, Norwegian Bay, and Viscount Melville Sound) there were insufficient data to provide an assessment of current trend. The type, precision, and time span of data used to estimate trends varies among subpopulations (PBSG 2015).

    Estimating Polar Bear abundance is expensive and difficult because the animals often occur at low densities in remote habitats. Although abundance estimates have generally improved in recent decades (Obbard et al. 2010), information remains poor or outdated for some subpopulations. Summing across the most recent estimates for the 19 subpopulations (Table 3 in the Supplementary Material) results in a total of approximately 26,000 Polar Bears ( 95% CI = 22,000-31,000 ). We note that this number differs from what would be obtained by summing abundance estimates in PBSG (2015), because criteria were not the same for including abundance estimates in the two sources (section Population projections). The total number presented here does not include the Arctic Basin subpopulation, for which no information on abundance is available. The 95% confidence intervals presented here were generated using simulation based on estimates of uncertainty in Table 3 and an assumption that the abundance of every subpopulation is independent of the others (see the section Population projections in the Supplementary Material). The mixed quality and even lack of available information on each subpopulation means caution is warranted when establishing and reporting a single estimate of the number of polar bears across the circumpolar Arctic. Therefore we used the abundance data in Table 3 in a relative manner, to scale subpopulation-specific changes to changes in the global population size, rather than in an absolute manner.
     
  5. fncceo
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    fncceo Gold Member

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    Po Po Bears?

    [​IMG]
     
  6. Crick
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    Crick Gold Member

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    Wow. Thanks for that. Very informative. You and Moshe watching cartoons on a Saturday morning?
     

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