Scat DNA Applications for Low-Density Carnivore Survey:
Techniques, Efficiency and Future Directions

Background: Large and mesocarnivores often occur at low densities due to both natural factors and human activities. Consequently, the noninvasive collection of carnivore data, such as scats for genetic analyses, provides a robust alternative to capture-based data.

Aims: In this review, we focussed on low-density carnivores to answer the following questions: What are the applications for scat-derived DNA samples? What is the sampling effort required and how efficient is scat DNA for detecting species compared to other methods? What are the methodological advances in scat DNA analyses?

Material & Methods: We systematicaly compiled the results of 338 studies applying scat DNA as a reliable source of genetic material for a myriad of applications. Most studies were conducted in Asia and Europe, encompassing mainly Felidae, Canidae and Mustelidae species.

Results and Discussion: In general, studies recommend allowing enough time for scats to accumulate in the field, but collecting before significant DNA degradation occurs. Storage and extraction can be successfully achieved using various methods, although commercial extraction kits have become more widely used over time. However, scat samples show an inherent high variability in amplification success rate. Considering the collection of scats on transects, the average distance travelled to encounter a molecularly identified scat was 6.9km. Faecal DNA was found to be more and equally efficient in detecting the number of individuals and the species present, respectively, compared to alternative methods.

Conclusion: The information presented here should guide new studies focussing on low-density carnivores, providing a basis for more cost-effective surveys and improving data quality for carnivore conservation.