Substrate and species constraints on the use of track incidences to estimate African large carnivore abundance

Population size and trends of large carnivores are difficult to determine, but are often needed to inform conservation actions. Direct counts maintained over long time periods are extremely difficult to achieve. Indices of population sizes can be used to estimate large carnivore abundances, but are often case-, species- and site-specific. Here, we test the general applicability of track-based indices to estimate large carnivore abundance. We surveyed 15 306.4 km of roads associated with 339 transects across a wide geographical scale, large range of densities and variable substrates for tracks of African large carnivores. A combined model for all carnivore species on sandy soils serves as a robust approach to predict large carnivore densities. Thus, indices based on track counts can provide useful estimates of carnivore abundance. We found consistent relationships between track densities and the actual carnivore densities, having taken account of substrate.