Temporal variation in food habits of the American Black Bear (<em>Ursus americanus</em>) in the boreal forest of northern Ontario

Abstract

We used scat analysis to investigate temporal variation in the food habits of American Black Bears (Ursus americanus) in the boreal forest of northern Ontario. Specifically, we examined whether there was a seasonal shift in foraging over three years (1990–1992) and which foods, if any, varied in occurrence among years. American Black Bears ate foods ranging from green vegetation in the spring to ants in mid-summer and berries and nuts in late summer and fall. Late summer berry forage, especially blueberries (Vaccinium spp.), varied greatly among years. American Black Bears in northern Ontario consumed a variety of foods opportunistically. Understanding how American Black Bears in northern Ontario exploit food resources and how these food items vary among years can provide insights into demographic processes and help wildlife managers better anticipate changes in the structure of the harvest of American Black Bears and in human–bear conflict levels. In northern Ontario, forest management practices that increase the availability of early successional species would be beneficial to American Black Bear populations.

Relationships among food availability, harvest, and human–bear conflict at landscape scales in Ontario, Canada

“…No significant relationships were detected in NWR, where the BFI did not vary synchronously among Districts (BFI data from NWR were sparse compared with other Regions). Significant correlations at the provincial scale were likely a result of the consistent patterns of variation in the BFI and measures of HBC and harvest that prevailed in NER and SR. Our BFI was largely based on annual rankings for soft-mast-producing species, which were previously shown to vary synchronously within and among species over subsets of our study area (Obbard et al 2003, Howe et al 2012, Romain et al 2013. Similar synchrony in soft mast production was also observed over large areas of Minnesota, USA (Garshelis and Noyce 2008), and Yukon, Canada (Krebs et al 2010).…”

“…1; Table 1). We selected these species based on their prevalence in the respective Forest Region, and with reference to studies of black bear feeding habits in Ontario and similar habitat elsewhere (Rowe 1972, Obbard 1987, Rogers and Allen 1987, Noyce and Garshelis 1997, Romain et al 2013; Table 1). All were native to Ontario, except feral domestic apples (Malus pumila) present in eastern and western Great Lakes-St. Lawrence Forests, and European mountain-ash (Sorbus aucuparia), which contributed to scores for mountain-ash (Sorbus spp.)…”

“…However, given the degree to which natural food supply for black bears varies among years (Costello et al 2003, Usui et al 2005, Romain et al 2013, Koenig and Knops 2014, and the importance of bottom-up processes to bear demography (McLellan 2011), it seems likely that bears at a range of population densities will attempt to access anthropogenic food sources and come into conflict with humans when natural foods are scarce. We suggest that reducing the associated risk of HBC through harvest would require high harvest levels that reduce populations to very low densities.…”

“…Although we did not detect significant trends in the number of hunters or total harvest, both were highest during the last 3 years of the study in SR, which would have contributed to the significant correlation. Black bears in the boreal forest of Ontario rely heavily on the fruits of a few plant species ( (Romain et al 2013). Fruit production by these species, and consumption by black bears, varies considerably among years (Usui et al 2005, Romain et al 2013.…”

“…Black bears in the boreal forest of Ontario rely heavily on the fruits of a few plant species ( (Romain et al 2013). Fruit production by these species, and consumption by black bears, varies considerably among years (Usui et al 2005, Romain et al 2013. Furthermore, fruit production by many of these species is adversely affected by late spring frosts and by dry or cool summer weather conditions (Usui et al 2005, Howe et al 2012, Romain et al 2013.…”