Winter Foraging Ecology of Woodland Caribou in Northeastern Washington

1996 ◽  
Vol 60 (4) ◽  
pp. 719 ◽  
Author(s):  
Eric M. Rominger ◽  
Charles T. Robbins ◽  
Marc A. Evans
Keyword(s):  
Foraging Ecology ◽  
Woodland Caribou ◽  
Winter Foraging

Winter Foraging Ecology of Moose on Glyphosate-Treated Clearcuts in Maine

1996 ◽  
Vol 60 (4) ◽  
pp. 753 ◽  
Author(s):  
Kevin S. Raymond ◽  
Frederick A. Servello ◽  
Brad Griffith ◽  
William E. Eschholz
Keyword(s):  
Foraging Ecology ◽  
Winter Foraging

scholarly journals Winter foraging ecology of Greater Sage-Grouse in a post-fire landscape

2020 ◽  
Vol 178 ◽  
pp. 104154 ◽  
Author(s):  
Marcella R. Fremgen-Tarantino ◽  
Jacqueline J. Peña ◽  
John W. Connelly ◽  
Jennifer Sorensen Forbey
Keyword(s):  
Foraging Ecology ◽  
Sage Grouse ◽  
Winter Foraging

scholarly journals The role of predation in the decline and extirpation of woodland caribou

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
ARE Sinclair ◽  
BN McLellan
Keyword(s):  
Rangifer Tarandus ◽  
Population Decline ◽  
Temporal Distribution ◽  
Pregnancy Rates ◽  
Foraging Habitat ◽  
Woodland Caribou ◽  
Instantaneous Rate ◽  
Population Growth Rates ◽  
Rate Of Increase ◽  
Winter Foraging

To select appropriate recovery strategies for endangered populations, we must understand the dynamics of small populations and distinguish between the possible causes that drive such populations to low numbers. It has been suggested that the pattern of population decline may be inversely density-dependent with population growth rates decreasing as populations become very small; however, empirical evidence of such accelerated declines at low densities is rare. Here we analyzed the pattern of decline of a threatened population of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada. Using information on the instantaneous rate of increase relative to caribou density in suitable winter foraging habitat, as well as on pregnancy rates and on causes and temporal distribution of mortalities from a sample of 349 radiocollared animals from 15 subpopulations, we tested 3 hypothesized causes of decline: (a) food regulation caused by loss of suitable winter foraging habitat, (b) predation-sensitive foraging caused by loss of suitable winter foraging habitat and (c) predation with caribou being secondary prey. Population sizes of caribou subpopulations ranged from <5 to >500 individuals. Our results showed that the rates of increase of these subpopulations varied from -0.1871 to 0.0496 with smaller subpopulations declining faster than larger subpopulations. Rates of increase were positively related to the density of caribou in suitable winter foraging habitat. Pregnancy rates averaged 92.4% ±2.24 and did not differ among subpopulations. In addition, we found predation to be the primary cause of mortality in 11 of 13 subpopulations with known causes of mortality and predation predominantly occurred during summer. These results are consistent with predictions that caribou subpopulations are declining as a consequence of increased predation. Recovery of these woodland caribou will thus require a multispecies perspective and an appreciation for the influence of inverse density dependence on population trajectories. © Springer-Verlag 2005.

scholarly journals Stable isotopes document the winter foraging ecology of king penguins and highlight connectivity between subantarctic and Antarctic ecosystems

2018 ◽  
Vol 8 (5) ◽  
pp. 2752-2765 ◽  
Author(s):  
Yves Cherel ◽  
Charline Parenteau ◽  
Paco Bustamante ◽  
Charles-André Bost
Keyword(s):  
Stable Isotopes ◽  
Foraging Ecology ◽  
Winter Foraging

Winter Foraging Ecology of Bald Eagles in Arizona

The Condor ◽  
1993 ◽  
Vol 95 (1) ◽  
pp. 132-138 ◽  
Author(s):  
Bryan T. Brown
Keyword(s):  
Foraging Ecology ◽  
Bald Eagles ◽  
Winter Foraging

scholarly journals The role of predation in the decline and extirpation of woodland caribou

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
ARE Sinclair ◽  
BN McLellan
Keyword(s):  
Rangifer Tarandus ◽  
Population Decline ◽  
Temporal Distribution ◽  
Pregnancy Rates ◽  
Foraging Habitat ◽  
Woodland Caribou ◽  
Instantaneous Rate ◽  
Population Growth Rates ◽  
Rate Of Increase ◽  
Winter Foraging

To select appropriate recovery strategies for endangered populations, we must understand the dynamics of small populations and distinguish between the possible causes that drive such populations to low numbers. It has been suggested that the pattern of population decline may be inversely density-dependent with population growth rates decreasing as populations become very small; however, empirical evidence of such accelerated declines at low densities is rare. Here we analyzed the pattern of decline of a threatened population of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada. Using information on the instantaneous rate of increase relative to caribou density in suitable winter foraging habitat, as well as on pregnancy rates and on causes and temporal distribution of mortalities from a sample of 349 radiocollared animals from 15 subpopulations, we tested 3 hypothesized causes of decline: (a) food regulation caused by loss of suitable winter foraging habitat, (b) predation-sensitive foraging caused by loss of suitable winter foraging habitat and (c) predation with caribou being secondary prey. Population sizes of caribou subpopulations ranged from <5 to >500 individuals. Our results showed that the rates of increase of these subpopulations varied from -0.1871 to 0.0496 with smaller subpopulations declining faster than larger subpopulations. Rates of increase were positively related to the density of caribou in suitable winter foraging habitat. Pregnancy rates averaged 92.4% ±2.24 and did not differ among subpopulations. In addition, we found predation to be the primary cause of mortality in 11 of 13 subpopulations with known causes of mortality and predation predominantly occurred during summer. These results are consistent with predictions that caribou subpopulations are declining as a consequence of increased predation. Recovery of these woodland caribou will thus require a multispecies perspective and an appreciation for the influence of inverse density dependence on population trajectories. © Springer-Verlag 2005.

Range shift and winter foraging ecology of a population of Arctic tundra caribou

2001 ◽  
Vol 79 (5) ◽  
pp. 746-758 ◽  
Author(s):  
Michael AD Ferguson ◽  
Line Gauthier ◽  
François Messier
Keyword(s):  
Rangifer Tarandus ◽  
Foraging Ecology ◽  
Food Selection ◽  
Arctic Tundra ◽  
High Arctic ◽  
Range Shift ◽  
Winter Range ◽  
Cassiope Tetragona ◽  
Winter Foraging

Some researchers have suggested that over periods of several decades, Arctic tundra caribou (Rangifer tarandus) may be regulated by density-dependent forage depletion. Winter range shifts could potentially delay such regulation when a population is at or near long-term maximum abundance. In the 1980s, Inuit correctly predicted the mass emigration of caribou from a traditional winter range on Foxe Peninsula (FP) on southern Baffin Island, Nunavut, Canada. Most FP caribou subsequently emigrated to a new winter range on Meta Incognita Peninsula (MIP). To determine if MIP provided emigrating caribou with better foraging habitats, we compared winter forage resources and snow cover at caribou foraging sites, and food selection by caribou on FP and MIP in April 1992. Caribou that remained on FP dug feeding craters in shallower, softer snow than those on MIP did. Biomass of most fruticose lichens was greater within foraging sites on MIP than on FP. Biomass of shrubs, other than Cassiope tetragona and Dryas integrifolia, was also greater on MIP than on FP. Dryas integrifolia was the only plant class that had higher biomass on FP than on MIP. Cladina spp. / Cladonia spp., Sphaerophorus fragilis, and Cetraria nivalis occurred less frequently in the rumens of FP caribou. Proportions of fruticose lichens in rumens of caribou on both peninsulas were similar to those on other overgrazed and High Arctic tundra winter ranges. Caribou on FP showed a higher preference for the shrub C. tetragona. Biomasses of plants sensitive to long-term feeding or trampling by caribou (i.e., the five most common fruticose lichens, other shrubs, and plant debris) were consistently lower on FP, which is congruous with Inuit reports that long-term cumulative overgrazing had reduced the supply of important forage plants on FP sites that were accessible to caribou in winter. FP caribou that emigrated to MIP gained access to more abundant, higher quality forage resources than those that remained on FP. Because most FP caribou had emigrated, this South Baffin subpopulation escaped, at least temporarily, the regulating effects of historical cumulative overgrazing.

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