PARENT SESSION
Contributed Oral Session 88: Mammal Ecology: Habitat and Movement
Wednesday, August 10, 8:00 AM - 11:30 AM, Meeting Room 524 A, Level 5, Palais des congrès de Montréal
Habitat use and competitive asymmetries between adult and juvenile American marten.
Johnson, Cheryl Ann*,1, Fryxell, John M.1, Thompson, Ian 2, Baker, James A.3, 1 University of Guelph, Integrative Biology (Zoology), Guelph, Ontario, Canada2 Canadian Forestry Service, Sault Ste. Marie, Ontario, Canada3 Ontario Ministry of Natural Resources, Guelph, Ontario, Canada
ABSTRACT- An animal′s success at acquiring resources depends on both the intensity of competition and an individual′s competitive ability. Individuals will likely compete more intensely for resources in high quality areas, exacerbating competitive asymmetries. Conversely, competition and competitive asymmetries will likely be lower in areas of poor resource availability. We examined how competitive asymmetries between adult and juvenile American marten, Martes americana, influenced habitat use (i.e. resource needed for survival and reproduction). Marten were live-trapped and fitted with radio-transmitters in two landscapes of the boreal forest of northern Ontario: a unlogged forest 80yrs old and a logged forest 30-60 yrs old, the former being presumably of higher quality than the latter. We used the relationship of mass vs. body length (i.e. body condition) as our measure of competitive ability. Adult and juveniles had similar body condition in the logged landscape, whereas adults were in better condition than juveniles in unlogged landscape. We then tested for differences in habitat use between the two age classes in the two landscapes. We predicted that the asymmetry in body condition in the unlogged would result in greater differences in habitat use between juveniles and adults, with adults monopolizing habitats of high resource availability. Although adults and juveniles used different habitats with older marten preferring stands with more abundant prey, larger course woody debris, and greater canopy cover, the strength of partitioning did not differ between logged and unlogged landscapes. We discuss our findings in terms of adult survival and juvenile recruitment for marten populations in logged versus unlogged landscapes.
Key words: habitat use, competitive asymmetries, logged vs. unlogged landscapes, Martes americana