All About Animals

Anthropogenic and natural changes in Arctic environments, as well as recognition of the shortcomings of our knowledge of Polar Bear ecology, are increasing the challenges for Polar Bear conservation and management. Higher ambient temperatures and erratic weather fluctuations, symptoms of anthropogenic climate change, are increasing across the range of polar bears. Polar Bears are dependent upon Arctic sea ice for access to their prey. Their dependence on an ephemeral habitat that exists as a function of sea surface and atmospheric temperatures means that climate warming poses the single most important threat to the long-term persistence of Polar Bears. Changes in sea-ice are known to alter Polar Bear abundance, productivity, body condition, and distribution, continued climate warming will increase future uncertainty and pose severe risks to the welfare of Polar Bear subpopulations. Although Polar Bears living in historically colder regions, the Arctic might derive transient benefit from a climate-driven transition away from multi-year ice, the annual sea ice must persist long enough for Polar Bears to derive benefit from associated changes in seal availability and biological productivity. An annual ice-free period of ≥5 months is likely to lead to extended fasting, which is predicted to lead to increased reproductive failure and starvation. Nevertheless, uncertainty and regional variability in the near-term effects of climate change must be included in Polar Bear management and conservation plans.
Declining sea ice availability can impair the ability of pregnant females to reach traditional denning areas and increases of rain events will be detrimental for denning Polar Bears.
 

The occurrence of diseases and parasites in Polar Bears is rare compared with occurrences in other bears. However, with warming Arctic temperatures, altered climate could influence infectious disease epidemiology through mechanisms such as novel pathogen introduction due to range expansion of carrier animals and arthropod vectors; modification of host susceptibility; changes in pathogen evolution, transmission, and number of generations per year; host immunosuppression; shifts in main food sources; altered behaviour; and co-infections with multiple agents. As a result, the potential for exposure to pathogens and resulting disease outbreaks may become more significant threats as Polar Bears experience the cumulative effects of multiple stressors. Parasitic agents that have developmental stages outside the bodies of warm-blooded hosts will likely benefit from the warmer and wetter weather projected for the Arctic. Improved conditions for such parasites have already adversely affected the health of some Arctic mammals. Bacterial parasites also are likely to benefit from a warmer and wetter Arctic. As the effects of climate change become more prevalent, there is concern about the emergence of new pathogens within polar bear range, new threats from existing pathogens that may be able to infect immuno-compromised/stressed bears, and the potential for new and existing pathogens to cross human–animal boundaries. Because of the previous limited exposure of Polar Bears to diseases and parasites, researchers have as yet been unable to determine whether they will be more susceptible to new pathogens. However, concern is exacerbated by the fact that Polar Bears appear to have a naïve immune system, which may make them particularly vulnerable to infection. Many different pathogens have been found in seal species that are Polar Bear prey; the potential therefore exists for transmission of these diseases to Polar Bears. If Polar Bears become nutritionally stressed, altered foraging behaviours such as increased feeding on the internal organs of their primary prey and use of alternative foods may increase the potential for exposure to pathogens. Ensuring the long-term persistence of Polar Bears will necessitate understanding how a rapidly changing physical environment modulates exposure to disease risk factors and, ultimately, population health.

Oil development in the Arctic poses a wide of range of threats to Polar Bears ranging from oil spills to increased human-bear interactions. It is probable that an oil spill in sea ice habitat would result in oil being concentrated in leads and between ice floes resulting in both Plar Bears and their main prey (Ringed Seal and Bearded Seal) being directly exposed to oil. Polar Bears are often attracted by the smells and sound associated with human activity. Polar Bears are known to ingest plastic, styrofoam, lead acid batteries, tin cans, oil, and other hazardous materials with lethal consequences in some cases. Another concern is that seals covered in oil may be a major source of oil to polar bears. Although the biological threats and impacts of oil and gas activities on Polar Bears are reasonably well understood, mitigation and response plans are currently lacking. Moreover, how Polar Bears will be affected by other types of human activity are less well known.

Human caused habitat change and increasing human-bear interactions also must be incorporated into polar bear population projections and polar bear harvest management in the future. Due to increased access to pre­viously isolated areas, Polar Bears will face increased risks from a variety of human–bear interactions. New settlements are possible with industrial development, and expansion of tourist visitations is assured. Although the fact of human–bear interactions can be reasonably measured, we have a long way to go to understand the effect of such interactions. The added stresses, resulting from a “more crowded” Arctic, may play an important role in the future welfare of Polar Bears.