Environmental DNA (eDNA)-metabarcoding-based early monitoring and warning for invasive species in aquatic ecosystems.
Biological invasion is a major threat to multiple ecosystems across the globe, causing severe damages to ecological integrity, loss of biodiversity, economic and social development and even human health. With the rapid development in aquaculture, shipping and aquarium and ornamental trades in the past several decades, China has become one of the countries most influenced by invasive species. Studies have clearly shown that the development and application of robust early monitoring and warning is one of the most effective ways to prevent and possibly control invasive species in aquatic ecosystems. Compared to terrestrial ecosystems, there remain several technical difficulties for developing early monitoring and warning in aquatic habitats. The technical challenges are mainly due to several features of aquatic biological communities such as high biodiversity and complex structure, a large number of microscopic species, extremely low population density and lack of available taxonomic keys for species identification. With the rapid development of high-throughput sequencing techniques, environmental DNA (eDNA)-metabarcoding has become the top priority method for developing the early monitoring and warning programs in aquatic ecosystems. In this review, we aim to synthesize the research progress on eDNA-metabarcoding and its application to early monitoring and warning of invasive species in aquatic ecosystems. In addition, we briefly discuss the technological advantages of eDNA-metabarcoding for the early monitoring and warning programs. Finally, we propose research perspectives for solutions to technical issues for false positive and false negative errors in the eDNA-metabarcoding process.