Appendix F. Effect of cycle phase on lynx stable isotope ratios.
FIG. F1. Model outputs for 120oW longitude (open symbols) and 70oW longitude (closed symbols) are presented. We determined whether each lynx sample was collected from a population that was increasing (including the low point in the cycle) or decreasing (including the cycle peak) by visually examining published lynx harvest numbers (Elton and Nicholson 1942, Novak et al. 1987, Healy 2001, Statistics Canada 2005). Separate models relating carbon and nitrogen stable isotope ratios to longitude, latitude, season, cycle phase and their interactions were fit to the data. Since only six observations occurred in spring during a decreasing cycle, no interactions between season and cycle phase were included in the model. δ15N values were significantly greater during the decline phase than the increase phase (F1,191 = 25.05, P < 0.001). For δ13C there was a significant latitude by longitude by phase interaction (F1,188 = 4.25, P = 0.041).
Elton, C., and M. Nicholson. 1942. The ten-year cycle in numbers of the lynx in Canada. Journal of Animal Ecology 11:215244.
Healy, C., editor. 2001. Furbearer management report of survey and inventory activities 1 July 1997 30 June 2000. Alaska Department of Fish and Game, Juneau, Alaska, USA.
Novak, M., M. E. Obbard, J. G. Jones, R. Newman, A. Booth, A. J. Satterthwaite, and G. Linscombe. 1987. Furbearer Harvests in North America. Ontario Ministry of Natural Resources, North Bay, Ontario.
Statistics Canada. 2005. http://www.statcan.ca/.