Abstract:

Aims: Environmental DNA (eDNA) technology provides a non-invasive approach for biodiversity monitoring. Recent studies have demonstrated that airborne eDNA collected from the air can be utilized to monitor wildlife in forest ecosystems. Compared with other eDNA survey methods, airborne eDNA offers greater flexibility in sampling site selection, especially in survey areas lacking environmental media such as water bodies. Therefore, airborne eDNA holds significant potential for biodiversity monitoring in forest ecosystems. This study aims to assess the effectiveness of airborne eDNA in monitoring terrestrial vertebrate diversity in tropical rainforests. 

Methods: The research was conducted in a 20-hectare forest dynamics plot in Xishuangbanna, China. Airborne eDNA technology was employed to survey terrestrial vertebrate diversity, and results were compared with those obtained from infrared camera monitoring data. A total of 20 airborne eDNA samplers were deployed, and three 24-hour sampling sessions were conducted over six days in November 2023. Collected samples were amplified using 12SV05 primers targeting the 12S rRNA gene fragment and sequenced on the Illumina NovaSeq 6000 platform. Sequences data were taxonomically annotated, and species detection efficiency was compared between airborne eDNA and infrared cameras. 

Results: Across the three Airborne eDNA sampling sessions, 66 operational taxonomic units (OTUs) were detected, representing birds, mammals, reptiles, and amphibians. In comparison, 20 infrared cameras placed at the same sites recorded 15 mammal species and 15 bird species over 5,682 camera days. Comparative analyses revealed that airborne eDNA was more effective in detecting species diversity. Additionally, evaluation of the alpha diversity accumulation curve indicated that diversity accumulation curve indicated that the diversity plateaued when 10 airborne eDNA samples were collected. Suggesting that within the current experimental conditions, 10 samples collected over three days are sufficient for maximizing species detection. 

Conclusion: This study demonstrates that airborne eDNA serves as an effective tool for monitoring terrestrial vertebrate diversity in tropical rainforests, enabling rapid and comprehensive biodiversity assessments. Compared to infrared cameras, airborne eDNA shows distinct advantages in rapid species detection. Although the technology is still under development and its stability and accuracy under specific environmental conditions require further improvement, ongoing advancements are likely to establish airborne eDNA as a critical tool for cross-trophic and multi-species biodiversity monitoring. It holds strong potential to support large-scale, standardized biodiversity monitoring networks in China.

Key words: environmental DNA, airborne eDNA, DNA metabarcoding, biodiversity, animal diversity, forest dynamics plot