Climate warming and polar bears in the arctic
Download
1 / 14

Climate Warming and - PowerPoint PPT Presentation


  • 188 Views
  • Updated On :

„Possible Effects of Climate Warming on Selected Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“ Ian Stirling and Claire L. Parkinson Arctic, Vol 59, NO. 3 (September 2006), P.261-275 Climate Warming and Polar Bears in the Arctic

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Climate Warming and' - Roberta


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Climate warming and polar bears in the arctic l.jpg

„Possible Effects of Climate Warming on Selected Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

Ian Stirling and Claire L. Parkinson

Arctic, Vol 59, NO. 3 (September 2006), P.261-275

Climate Warming and Polar Bears in the Arctic

http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/primary/polar-bear-wet.jpg


Hypothesis l.jpg

„In this paper, Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

we evaluate patterns of sea-ice breakup (...)

to test the hypothesis that sightings of more polar bears in these populations are due in part to changes in sea ice, possibly resulting from climate warming, and do not necessarily indicate population increases.“

Hypothesis


Picture from the discussed paper p 263 l.jpg

Picture from the discussed paper, p. 263 Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

Study Area: Eastern Canadian Arctic

http://www.map-of-canada.org/canada-map.gif


The five areas are ice free in summer they are chosen according to polar bear subpopulations l.jpg

The five areas are ice-free in summer Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

They are chosen according to polar bear subpopulations

Study Area: Eastern Canadic Arctic


Methods measurement of sea ice l.jpg

-Satellite data from 1972 to 2004 Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

-Measurement of microwave radiance:

→Easily pass through most clouds

→Ice and water differ

-Used in this study:→ Date on wich the total cover of sea ice declined to 50%

→Ecologically significant (other study)

Methods: Measurement of Sea Ice


Results and discussion l.jpg
Results and Discussion Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“


Western hudson bay results l.jpg

Western Hudson Bay – Results Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

p=0.003


Western hudson bay discussion l.jpg
Western Hudson Bay – Discussion Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

  • polar bearsareforcedtocomeashoreearlierandto fast earlierandlonger

  • relationshipbetweendateofbreakupandconditionofthebears (Stirling et al. 1999)

  • polar bearpopulationdeclinedby 22 % between 1987 and 2004 (Regehr et al. 2005)

    → morelikelythatmore polar bearsareseennearcostalsettlementsbecausetheyarehungryratherthantheirpopulationhasincreased


Davis strait results l.jpg
Davis Strait – Results Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

p=0.35


Davis strait discussion l.jpg
Davis Strait – Discussion Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

  • unknownsizeof polar bearpopulation

  • increasedabundanceofpreybetween 1970s and 1990s, stabilized in theearly 1990s

    → probably polar bearpopulationincreasedbetween 1970s and 1990s, but itislikelythatpopulationis not longerincreasing


Evaluation strengths l.jpg
Evaluation: Strengths Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

  • Long observation period (over 30 years)‏

  • Reliable data source (satellites)‏

  • Large study area

  • Investigation of areas that are ecologically meaningful for the polar bear


Evaluation weakness 1 l.jpg
Evaluation: Weakness 1 Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

  • No division of results and discussion

  • This leads to Piramyding: They interlace own results, results from other studies and the discussion of both

  • Mixture of meta study and original study


Evaluation weakness 2 l.jpg
Evaluation: Weakness 2 Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

  • EHB: Their own data is not significant→They do not discuss why, mention other studies that support their thesisand conclude from the other studies (P. 271)

  • Much additional information that does not directely deal with the main thesis

  • Citation of unpublished results or observations from himself (9 times)‏


Own opinion in short l.jpg
Own Opinion in short Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic“

  • Good data and interpretation

  • The main points could have been summarized within 4 pages


ad