Comparison of point counts and automated acoustic monitoring: detecting birds in a rainforest biodiversity survey

To monitor assemblages of animals, ecologists need effective methods for detecting and recording the distributions of species within target areas in restricted periods of time. In this study, we compared the effectiveness of a traditional avian biodiversity assessment technique (point counts) with a relatively new method (automated acoustic recordings) along an elevational gradient in rainforest in central Queensland, Australia. On average, point counts detected more species than acoustic recordings of an equivalent length of time (n = 40, P = <0.001). We suggest these results are driven by the visual detection of additional species during point counts. Despite the fact that point counts detected more species than acoustic recordings, datasets generated by both methods showed similar patterns in the community response to change in elevation. There was significant overlap in the species detected using both methods, but each detected several unique species. Consequently, we recommend the use of both techniques in tandem for future biodiversity assessments, as their respective strengths and weaknesses are complementary.