Evaluating relative abundance indices for terrestrial herbivores from large-scale camera trap surveys

Palmer and colleagues used the extensive Snapshot Serengeti dataset to test how well camera-trap relative-abundance indices reflect true herbivore abundance, exploiting independent population information for validation. They examined how indices based on detection rates relate to actual densities across species and conditions, and how factors like body size, group size, and behavior distort the relationship. The results offered empirical support for cautious use of relative-abundance indices while documenting their biases and limitations. Because such indices are widely used when full density estimation is impractical, the study's evidence-based appraisal is valuable for interpreting them responsibly. It is a frequently cited reference in debates over the reliability of camera-trap detection rates as proxies for abundance.