Validation of a rigorous track classification technique: identifyingindividual mountain lions

摘要

Despite track survey efforts, the inability to identify individuals from survey data impedes accurate density estimates and density indices for large carnivore species. We present a track classification method for mountain lions Puma concolor using discriminant function analysis that improves and validates the method presented in Smallwood and Fitzhugh (1993) (Smallwood, K.S., Fitzhugh, E.L., 1993. A rigorous technique for identifying individual mountain lions Felis concolor by their tracks. Biological Conservation 65, 51-59) and Further discussed in Grigione, Burman, Bleich and Pierce, 1999 (Grigione, M.M., Burman, P., Bleich, V.C., Pierce, B.M., 1999. Identifying individual mountain lions Felis concolor by their tracks: refinement of an innovative technique. Biolkogical Conservation 88, 25-32). Artificial tracks, made from molded casts of the feet of 13 lions, were used to simulate variability from field conditions in a controlled laboratory setting. We tested the effects of multiple track recorders and two soil depths on linear and angular measurements of the entire paw and shape measurements of the heel-pad. We identified six track measurements that correctly matched 96% of track tracings to known individual mountain lions, even with variability from multiple track recorders and soil depths. Model validation, performed on lab and novel field data in which the number of individual mountain lions was unknown, illustrates the efficacy of the method. Following the field-based study by Smallwood and Fitzhugh (1993), this study provides support for the utility of the discriminant analysis method for track data and outlines future application of this method to held data.