A Bayesian Network Modeling Approach to Forecasting the 21st Century Worldwide Status of Polar Bears - Arctic Sea Ice Decline: Observations, Projections, Mechanisms, and Implications - page 236

Table A1. (continued)

Node
Name

Node Title Node Description States

becomes too expensive for people to venture to such remote areas or in the polar basin
divergent unit, when it is essentially devoid of ice, it may not attract many tourists and
such activity may surge and then decline in that region. The arctic areas with more
interesting coastlines etc., however, will probably see nothing but increases in tourism.
Contamination that may accompany such activities, and biological effects from intro-
duced organisms that may compete with residents of the food web or cause disease are
covered under the nodes for contamination and parasites and disease.

B1 Bear-human
interactions

This includes nonlethal takes which may increase as a result of increased human-bear
interactions because of food-stressed bears more frequently entering Arctic communi-
ties. Such takes can displace bears from their preferred locations and reduce habitat
quality.
This is separate from the similar interactions that may occur around oil and gas or
other industrial sites which also can displace bears and lower habitat quality.
These interactions also, however, can result in deaths as when problem bears are shot
in defense of life and property. So, this node includes a component of both habitat
quality and direct mortality.
I believe that bear-human interactions will increase until such time as areas are devoid
of bears or climate cools again and ice returns.

increased
same_as_now
decreased

R1 Oil and Gas

Activity

This refers to the spatial effects of oil and gas activity. It refers to activities and infra-
structure which may physically displace bears from habitat that was formally available
to them. It also can result in direct killings of bears which become a persistent safety
problem around industrial facilities.
Oil companies etc. have great resources to prevent these events from leading to
mortalities, but such mortalities cannot be totally avoided and are likely to increase as
habitat base shrinks.
I think oil and gas activity will increase in the polar basin region through mid century
and then decline because resources will have been tapped. We may see some increase
in exploration and development in the archipelago, however, as it becomes increas-
ingly accessible.

increase
no_change
decrease

J Shipping As sea ice extent declines spatially and temporally it is predicted that shipping in

Arctic regions will increase. Increased shipping could lead to direct disturbances of
polar bears as well as to increased levels of contamination. here, we address only the
physical presence of more vessel traffic. Contamination (bilge oil, etc.), and biological
effects from introduced organisms that may compete with residents of the food web or
cause disease are covered under the nodes for contamination and parasites and disease.
We allow only two states here: increased and same as now, because we can think of
no reason why shipping will decrease in the foreseeable future. Even if international
shipping does not increase, local shipping will, because barges and vessels are more
efficient ways to move fuel and freight into remote Arctic locations than aircraft.

increased
same_as_now

F Alternate

Regions
Available

Are there geographic ecoregions to which bears from the subject region may effec-
tively be able to relocate.
This ability is contingent on other ecoregions with suitable habitats being contiguous
with regions where habitat quantity or quality have degraded to the point they will not
support polar bears on a seasonal or annual basis. For example, if the sea ice is deterio-
rating throughout the polar basin including the Beaufort Sea and the last vestiges of ice
are along the Alaskan Coast, there may be no where else to go if the ice deteriorates
to an unsatisfactory state. If, however, the ice retreats to the northeast as its extent
reduces, bears remaining on the ice may have access to suitable habitats in the archi-
pelago or in NE Greenland.
I believe that bears in the seasonal ice region and in the polar basin will be able to col-
lapse into the archipelago. Ice patterns suggest that the remaining ice in the Arctic is

yes
no