Estimating larger carnivore numbers from track counts and measurements

Knowing the abundance of larger carnivores is critical for their conservation management. However, direct assessment of carnivore numbers is often difficult, expensive and time-consuming, leaving indirect sampling as a valid and feasible alternative. Indirect census techniques have proved to be cost-effective, repeatable and objective. We therefore estimated the numbers of six larger carnivore species in a relatively small area in northern South Africa, comparing three indirect sampling methods based on track counts and measurements: (i) a qualitative approach, whereby individuals were subjectively identified by comparing differences in track measurements; (ii) a quantitative approach using the strong linear correlation of track density with carnivore density found in other studies; and (iii) a quantitative approach applying repeated measures analysis of variance and post-tests to the track measurement data, in order to test statistically for differences in track sets. All three methods provided similar results that appear to be reasonable and which might be an indication of the real number of larger carnivores that occur in the study area. These results support the reliability of indirect estimates of larger carnivore numbers based on tracking data, which is promising for future research and conservation efforts involving these animals.