Monitoring forest biodiversity using DNA metabarcoding: high-throughput species identification of saproxylic beetles
Suivis de biodiversité forestière par métagénomique: identification à haut débit des coléoptères saproxyliques
Résumé
Saproxylic beetles – associated with dead wood or with other insects, fungi and microorganisms that decompose it – play a major role in forest nutrient cycling. They are important ecosystem service providers and are used as key bio-indicators of old-growth forests. In France alone, where the present study took place, there are about 2500 species distributed within 71 families. This high diversity represents a strong challenge for specimen sorting and identification. We have developed a DNA metabarcoding approach to facilitate and enhance the monitoring of saproxylic beetles as indicators in ecological studies. We use Illumina Mi-Seq to recover species diversity from bulk samples collected in interception traps. Sampling was designed to account for a variety of conditions and parameters possibly affecting the experiments. These include species diversity, relative abundance and biomass, sampling medium and preservation methods. DNA-based species identification derived from available records in public databases and from a newly assembled DNA barcode library for European species identified by expert taxonomists currently comprising 580 species (855 records in 47 families). Preliminary results show the potential of DNA metabarcoding to accurately identify saproxylic beetles from bulk samples collected with interception traps. Our approach opens new avenues of research using these insects as forest indicators.