Spatial and temporal interactions between female American black bears in mixed forests of eastern Canada

Few studies have examined in detail the spacing patterns of American black bears (Ursus americanus), especially populations protected from hunting. We radio-tracked bears between 1990 and 1992 in La Mauricie National Park in southern Quebec to study their social interactions. We measured the zone of overlap between home-range core areas and evaluated the spatial and temporal use of the overlap zones for 12 adult females radio-tracked during 1992. The proportion of overlap between the core areas used by 22 pairs of females was variable but low (14.2 ± 17.6% (mean ± SD)). This proportion did not differ (p > 0.05) from that obtained from a random distribution of home ranges (17.1 ± 17.1%). For 12 (55%) of 22 pairs with overlapping core areas, at least one of the females was significantly attracted by the overlap zone, whereas one of the females of another pair significantly avoided it. Significant simultaneous use of the overlap zone was observed for 7 pairs and significant temporal avoidance of the overlap zone was noted for 1 pair. The overlap zone contained a significantly higher proportion of food-producing cover types (maplebeech and early-successional stands) than the overall study area. Our results indicate that although most females did not share a large proportion of their core area with their neighbours, the overlap zone was used intensively for foraging by more than one bear, often simultaneously. Some aggressive behaviours were noted when bears were seen foraging simultaneously in the same area. We discuss the influence of spatial and temporal interactions on the regulation of this unhunted population.

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A distance-based analysis of habitat selection by American black bears (Ursus americanus) on the Bruce Peninsula, Ontario, Canada

Canadian Journal of Zoology ◽

10.1139/z10-072 ◽

2010 ◽

Vol 88 (11) ◽

pp. 1063-1076 ◽

Cited By ~ 11

Author(s):

Martyn E. Obbard ◽

Melissa B. Coady ◽

Bruce A. Pond ◽

James A. Schaefer ◽

Frank G. Burrows

Keyword(s):

Habitat Selection ◽

Ursus Americanus ◽

Deciduous Forest ◽

Mixed Forest ◽

Late Summer ◽

Black Bears ◽

Home Ranges ◽

Isolated Population ◽

American Black ◽

American Black Bears

Because of their wide-ranging habits, conserving large carnivores such as American black bears ( Ursus americanus Pallas, 1780) often depends on understanding habitat needs beyond the boundary of protected areas. We studied habitat selection by black bears in the vicinity of Bruce Peninsula National Park, Ontario — a small, isolated population whose persistence appears dependent on habitat on lands outside the Park. We used an approach based on Euclidean distances to document seasonal habitat selection at two spatial scales and to identify candidate habitat types for protection. Adult females selected dense mixed forests to establish home ranges within the population range, whereas subadults and yearlings selected dense deciduous forests. Within home ranges, adults selected dense mixed forest in spring–summer and dense deciduous forest in late summer – fall. Subadults selected dense deciduous forest, marsh, dense mixed forest, and water during the spring–summer and avoided developed lands and roads. Yearlings selected dense mixed forest, dense deciduous forest, and sparse forests in spring–summer and dense deciduous forest and dense mixed forest in late summer – fall. The selection of dense deciduous and dense mixed forest stands, especially at the broader scale, suggests that strategies to ensure persistence of this isolated population should focus on protecting the integrity of these stands.

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