Introduction/Background/Justification : The rainforests of the Neotropics shelter a vast diversity of plant, animal and microscopic species that provide critical ecosystem goods and services for both local and worldwide populations. These environments face a major crisis due to increased deforestation, pollution, and climate change, emphasizing the need for more effective conservation efforts. The adequate monitoring of these ecosystems is a complex and time consuming endeavour. To date, many species remain undiscovered, let alone described, with otherwise limited information regarding known species population distributions and densities. Overcoming these knowledge shortfalls and practical limitations is becoming increasingly possible through techniques based on environmental DNA (eDNA), i.e., DNA that can be obtained from environmental samples (e.g. tissues, soil, sediment, water, etc.). When coupled with high-throughput sequencing, these techniques now enable realistic, cost-effective, and standardisable biodiversity assessments. This opens up enormous opportunities for advancing our understanding of complex and species-rich tropical communities, but also in facilitating large-scale biomonitoring programs in the neotropics.

Objectives: Provide an introduction to eDNA methods and an overview of their current and potential uses in terrestrial ecosystems of neotropical rainforests.

Methods: This presentation will rely on different studies making use of DNA metabarcoding and high-throughput sequencing, applied to soil samples that were collected in various forest ecosystems in French Guyana, and for which a variety of genomic markers are studied, hence allowing covering biodiversity in a multi-trophic perspective, from micro-organisms to plants. Natural, urban, or anthropogenically disturbed forests will be considered in order to address a variety of questions, from community assembly processes to human impacts on biodiversity.

Results and Implications: I will discuss the limits and challenges of eDNA-based methods for our understanding and monitoring of multi-trophic biodiversity in neotropical rainforests, as well as future research and applied perspectives of these techniques for these environments.