The flora and fauna of the nature get always confronted with the ever changing climactic challenges that vary from region to region. There may be many possible reasons like depletion of natural resources, global warming, natural calamities etc. But, together these changes may also lead to species extinction.
There is a need for early intervention programs to control this problematic issue. So, the present description deals with highlighting about one such issue by considering the endangered species Polar Bear.
Polar bears (Ursus maritimus) are considered as major carnivores confined to Arctic regions. They exhibit great variation in their body weight depending on their age and sex. This may appear as an important factor to consider.
Previous workers studied sexual dimorphism in body mass, body length, and head size of polar bears from the live-captured polar bears in Norway. They reported that sexual dimorphism in adults was due to higher growth rate and prolonged growth period in males and that in the case of mature bears sexual dimorphism was greatest in mass, followed by good foreleg guard hair length and body length. It can be inferred that the sexual dimorphism may be an adaptation to the Arctic climate that may determine their survival (Andrew, 2005).
It was projected that the population of polar bears would come down to only two thirds of the current number because of industrial fossil fuel induced global warming. This is because of the rising temperatures that contribute to the melting of ice.
As such, the reported consequences are thinner bears, decreased reproduction rate and reduced juvenile survival. This has resulted in declaring polar bear as an endangered species. The benefits of such action may be that polar bears would have some survival chances of when there would be reduction in the emission of fossil fuels and their total cessation in industries.
Further, there may be also a need of other strategies to adopt in addition to imposing rules on industries. It was revealed that minute temperature differences could tremendously affect the extent and thickness of sea ice, making the polar marine ecosystems sensitive to climate change (Smetacek & Nicol, 2005).
Therefore, there is a need to understand the effects of human exploitation of upper trophic levels from basin-wide, decade-scale climate cycles to identify long-term, global trends. This is reported to help in better predicting the association among the community of polar organisms which in turn might reflect the availability of their planktonic food supply (Smetacek & Nicol, 2005).
This information could also help in saving the polar bear from the threat of extinction.
Earlier researchers evaluated capture procedures with regard to conservation, research, and management of wild bears (Marc Cattet et al., 2008).
It was revealed that persons engaged in wildlife capture should examine their capture procedures and research results carefully which might help them to avoid potentially erroneous interpretations (Marc Cattet et al., 2008).
Here, it may imply that although polar bears are not subject to capture procedures conservation biologists should review various research results concerned with the protection of polar bears for gaining better insights.
Recently, it was described that warming is becoming more prevalent across the Arctic Ocean Basin and along the Antarctic Peninsula, with significant reduction in the extent and seasonal duration of sea ice (Moline et al., 2008).
The consequences of such climate-mediated changes could lead to temporal asynchronies and spatial separations between energy requirements and food availability for many higher trophic levels where polar bear is one of the organisms. This is also reported to result in decreased reproductive success, lower abundances, and changes in distribution (Moline et al., 2008).
Therefore, in view of this cascade of changes following a warming, it may appear that the climatic changes especially the appearance of glaciers and ice sheets may serve as an early predictor of the habitat of polar bear and other marine organisms (Moline et al., 2008).
This was further strengthened by another report that highlighted polar bear demography and conditions with regard to the impacts of climate change. Here, it was described that a decreased sea ice habitat would reduce the availability of ice associated seals, the main prey of polar bears, and a loss and fragmentation of polar bear habitat would ultimately lead to large future reductions in most subpopulations (Wiig, Aars, & Born, 2008).
These climatic changes might have also occurred earlier and definitely prompted biologists to propose a list comprising of endangered species which may require the knowledge of Taxonomy.
Earlier there were certain problems with regard to the species and sub-species concepts as the management agencies were trapped by uncertainties about taxonomic standards during listing or delisting activities. The researchers have suggested taxonomic societies to publish and periodically update peer-reviewed species for efficient taxonomic conservation to take place (Haig et al., 2006).
Recent advancements in science have prompted the utility of genetic information in determining whether species, subspecies, and distinct population segments qualify for protection under the U.S. Endangered Species Act (Fallon, 2007). It was further described that multiple genetic markers would more possibly detect the distinctions, and those organisms were more likely to receive protection than studies that relied on a single genetic marker (Fallon, 2007).
Hence, all the above research descriptions may have proven influential in perfectly making the U.S. Fish and Wildlife Service to list the polar bear as a threatened species under the Endangered Species Act on May 15th 2008. Therefore, it an be concluded that the Polar bear has drawn the attention of biologists with regard to its unique habitat which is under constant threat.
Andrew E. Derocher, Magnus Andersen, Øystein Wiig.2005. “Sexual Dimorphism of Polar Bears.” Journal of Mammalogy 86(2005): pp. 895–901.
Fallon, SM. “Genetic data and the listing of species under the U.S. Endangered Species Act.” 2007.Conserv Biol 21.5 (2007): pp.1186-95.
Haig, SM, Beever, EA, Chambers, SM, Draheim, HM, Dugger, BD, Dunham, S, Elliott-Smith, E, Fontaine, JB, Kesler, DC, Knaus, BJ, Lopes, IF, Loschl, P, Mullins, TD, Sheffield, LM. “Taxonomic considerations in listing subspecies under the U.S. Endangered Species Act.” Conserv Biol 20.6(2006): 1584-94.
Marc Cattet, John Boulanger, Gordon Stenhouse, Roger, A. Powell, Melissa, J. Reynolds-Hogland. “An Evaluation of Long-term Capture Effects in Ursids: Implications for Wildlife Welfare and Research.” Journal of Mammalogy 89.4 (2008): 973–990
Moline, MA, Karnovsky NJ, Brown Z, Divoky GJ, Frazer TK, Jacoby CA, Torres JJ, Fraser WR. “High latitude changes in ice dynamics and their impact on polar marine ecosystems.” Ann N Y Acad Sci 1134 (2008):267-319.
Smetacek, V., & Nicol, S. “Polar ocean ecosystems in a changing world”. Nature 437 (2005): 362-8.
Wiig Ø, Aars, J, & Born, EW. “Effects of climate change on polar bears.” Sci Prog 91(2008):151-73.
Endangered animals – Polar bear.
Polar bear (Ursus maritimus). 2008.