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In 2023, zoologists of the Plant Science and Biodeversity Centre SAS published a Pan-European study in which they described in detail the current state of species diversity and distribution of two important groups of aquatic insects (beetles - Coleoptera, bugs - Heteroptera) and then precisely defined the level of DNA barcoding data used for effective determination of species in international reference databases. In total, the study analyzed faunal and barcoding data on more than 1,500 species.

A reliable assessment of biodiversity and the ecological state of ecosystems requires high-quality and up-to-date data, which is why interest in determination methods based on DNA and massive parallel sequencing has been growing intensively recently.  The basis of routine molecular identification of species (DNA metabarcoding) is high-quality databases of reference DNA barcodes, but the coverage of species with barcodes is still relatively low. The progress in this area requires information about where the gaps are, how big they are, and why they persist. The aim of this study was to describe and understand the current state of knowledge regarding the number and distribution of species and the availability of DNA barcodes through the example of two model groups of aquatic insects and to offer solutions for improvement. Since the databases are gradually developing, the analyzes were carried out in the past three years (2020 to 2022). The results of the study confirmed that despite several barcoding campaigns, DNA barcodes are only available for approximately 50% of the species from the European fauna of both studied groups. The worst situation is in the Mediterranean, the Balkans and Southeast Europe. Each year, the analyzes showed very little increase in species coverage (less than 1% for European aquatic beetles) despite an approximately 25% increase in the number of barcodes published. In addition to geographic characteristics, the analyzes also identified differences between countries and the main factors influencing progress in building reference DNA barcode libraries.

The team of authors recommended specific changes in the approach to supplementing reference DNA data with an emphasis on quality over quantity, greater involvement of taxonomy experts, and targeted studies on underexplored but biodiversity-rich areas. These recommendations aim to optimize the process of species identification through DNA, which is of key importance for further research in the field of ecology of freshwater communities, biomonitoring, agroecology or nature conservation. The publication provides a detailed analysis and recommendations that will enable more efficient identification of species at the European level, representing an important step towards a comprehensive understanding of the state of nature and effective protection of biodiversity.

Source and photo: Institute of Botany SAS