title: Wolves adapt territory size, not pack size to local habitat quality.
abstract: 1. Although local variation in territorial predator density is often correlated with habitat quality, the causal mechanism underlying this frequently observed association is poorly understood and could stem from facultative adjustment in either group size or territory size. 2. To test between these alternative hypotheses, we used a novel statistical framework to construct a winter population-level utilization distribution for wolves (Canis lupus) in northern Ontario, which we then linked to a suite of environmental variables to determine factors influencing wolf space use. Next, we compared habitat quality metrics emerging from this analysis as well as an independent measure of prey abundance, with pack size and territory size to investigate which hypothesis was most supported by the data. 3. We show that wolf space use patterns were concentrated near deciduous, mixed deciduous/coniferous and disturbed forest stands favoured by moose (Alces alces), the predominant prey species in the diet of wolves in northern Ontario, and in proximity to linear corridors, including shorelines and road networks remaining from commercial forestry activities. 4. We then demonstrate that landscape metrics of wolf habitat quality - projected wolf use, probability of moose occupancy and proportion of preferred land cover classes - were inversely related to territory size but unrelated to pack size. 5. These results suggest that wolves in boreal ecosystems alter territory size, but not pack size, in response to local variation in habitat quality. This could be an adaptive strategy to balance trade-offs between territorial defence costs and energetic gains due to resource acquisition. That pack size was not responsive to habitat quality suggests that variation in group size is influenced by other factors such as intraspecific competition between wolf packs.
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Andrew M
authors.identifier: http://orcid.org/0000-0002-7334-4766
authors.initials: AM
authors.lastname: Kittle
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Morgan
authors.initials: M
authors.lastname: Anderson
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Tal
authors.initials: T
authors.lastname: Avgar
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: James A
authors.initials: JA
authors.lastname: Baker
authors.affiliation: Ontario Ministry of Natural Resources, 1235 Queen Street East, Sault Ste. Marie, Ontario, P6A 2E5, Canada.
authors.forename: Glen S
authors.initials: GS
authors.lastname: Brown
authors.affiliation: Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Jevon
authors.initials: J
authors.lastname: Hagens
authors.affiliation: Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Ed
authors.initials: E
authors.lastname: Iwachewski
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: Moffatt
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Anna
authors.initials: A
authors.lastname: Mosser
authors.affiliation: Wildlife Research and Development Section, Ontario Ministry of Natural Resources, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario, K9J 7B8, Canada.
authors.forename: Brent R
authors.initials: BR
authors.lastname: Patterson
authors.affiliation: Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Douglas E B
authors.initials: DE
authors.lastname: Reid
authors.affiliation: Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Rodgers
authors.affiliation: Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Thunder Bay, Ontario, P7B 5E1, Canada.
authors.forename: Jen
authors.initials: J
authors.lastname: Shuter
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Garrett M
authors.initials: GM
authors.lastname: Street
authors.affiliation: Canadian Forest Service, 1219 Queen Street East, Sault Ste. Marie, Ontario, P6A 2E5, Canada.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Thompson
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: Lucas M
authors.initials: LM
authors.lastname: Vander Vennen
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada.
authors.forename: John M
authors.initials: JM
authors.lastname: Fryxell
mesh_terms: D000818:Animals; D017753:Ecosystem; D040362:Geographic Information Systems; D009864:Ontario; D012621:Seasons; D012919:Social Behavior; D013731:Territoriality; D019596:Wolves / Q000502:physiology*
keywords: Brownian bridge; anthropogenic disturbance; boreal forest; generalized least squares; optimal group size; predator density; repeated measures; rubber disc hypothesis; spatial autocorrelation; territoriality