Oral Presentation- Symposium 12th International Mammalogical Congress

Conspecific competition and resource depression affect movement and home range establishment of translocated fishers (Pekania pennanti) (#68)

Aaron N Facka 1 , Roger A Powell 2
  1. Oregon State University, Portland, OR, United States
  2. Department of Applied Ecology, North Carolina State University, Raleigh, NC, United States

Experience and information should be advantageous to residents of a home range but put invaders at a disadvantage causing them to establish their home ranges elsewhere. Conspecifics should avoid the home ranges of one another to ensure they are not altering resource availability, but encountering one competitor (e.g., dominant or of a different sex) may cause an individual to discount resource patches differently compared to if they encountered another conspecific. We tested the hypothesis that female and male carnivores responded differently to the presence of sex-specific competitors. We tested our hypothesis by selectively releasing newly moved fishers (Pekania pennanti) in the presence or absence of already established fisher home ranges during a reintroduced into northern California over 3 years from late 2009 to 2011. Using satellite transmitters (Argos) and land-based (VHF) telemetry we made daily observations of fisher locations, movements and area of their minimum convex polygons during their first 200 hundred time steps after release. Females that encountered the home range of any conspecifics moved further, had larger minimum convex polygons and settled further from their release locations than did females that did not encounter a conspecific home range. Males did not avoid, or appeared indifferent, to the home ranges of all conspecifics but males released in the absence of females moved more. Our results suggest that female fishers avoided conspecific competition from both males and females in accordance with our hypothesis. Males appeared motivated by the absence of females and by the type of sex-specific competitor they encountered.