Table 1.
Sampling effort each year during helicopter surveys for signs of polar bears, seals, and Arctic foxes on the sea ice of western Hudson Bay.
Fig 1.
Study area (blue bounding box) delimited by minimum convex polygon of all helicopter locations pooled over 2019 to 2024.
The grey dashed line represents the typical boundary of the landfast ice.
Table 2.
Summary of the layers used for hotspot calculation in this study. We provide hotspot names used throughout the text, description, type, brief explanation of the ecological insight it provides, and sample size used for hotspot calculation.
Table 3.
Raw observation counts per category (fox tracks and bear tracks were not recorded in 2019). 8 seal kills from 2022, 4 from 2023 and 8 from 2024 occurred at lairs or breathing holes and were combined with polar bear digs of lairs and breathing holes to calculate the hotspot “structure”.
Fig 2.
Maps of the study area in western Hudson Bay with species hotspots and hotspot of events of seal predation by polar bears estimated with the Getis-Ord Gi* statistics.
Darker levels of red represent increasing levels of statistical significance. Note that we display statistically significant hotspots up to α = 0.1 but only use hotspots statistically significant at α ≤ 0.05 in subsequent spatial analyses.
Table 4.
Hotspot area per species, interspecific area of overlap, and corresponding proportion of mutual or directional overlap. Hotspot area of seal kill and structure overlap are directional (proportion of seal-kill or structure hotspot area overlapping polar bear and seal species hotspot area, and Arctic fox hotspot area overlapping seal-kill or structure hotspot).
Fig 3.
Hotspots, hotspot centroids, and hotspot overlap between species pairs (Arctic fox in blue, polar bear in yellow, ringed seal in grey, bearded seal in pink, seal kill in red, structure in orange) in the study area near Churchill, Manitoba.
Hotspots were calculated using the Getis-Ord Gi* statistic. We extracted the hotspot area statistically significant at α ≤ 0.05 to produce the overlaps.