Rapid Environmental Change Drives Increased Land Use by an Arctic Marine Predator

Area of Science:

• Arctic ecology
• Climate change impacts
• Wildlife behavior

Background:

• Sea ice in the southern Beaufort Sea has a significantly longer melt season since the late 1990s.
• Polar bears historically relied on sea ice, but are increasingly using terrestrial habitats.

Purpose of the Study:

• To investigate the spatial behavior of polar bears on land during summer and fall.
• To understand the link between environmental changes and increased use of terrestrial habitats by polar bears.

Main Methods:

• Tracking radiocollared adult female polar bears in the southern Beaufort Sea subpopulation.
• Analyzing trends in arrival on shore, duration of stay, and departure back to sea ice.
• Correlating polar bear movements with sea ice availability and phenology.

Main Results:

• The proportion of radiocollared adult females coming ashore has tripled over 15 years.
• Polar bears are arriving on shore earlier, staying longer, and departing later.
• Increased duration on shore (31 days) correlates with a longer open-water season (36 days).
• Onshore distribution is influenced by scavenged whale remains.

Conclusions:

• Declining sea ice and increased availability of human-provided resources drive greater land use by polar bears.
• Extended periods on land raise concerns about increased exposure to human-related risks.