Molecular analysis of invasive aquatic macrophytes: an approach to biodiversity conservation.

Abstract

Invasive alien species represent one of the greatest threats to biodiversity, being the second leading cause of loss of biological diversity. In Brazil, the intentional introduction of exotic plants is a significant factor. In Brazilian freshwater ecosystems, 12 species of invasive aquatic macrophytes have been identified, including Urochloa arrecta, U. mutica, Hedychium coronarium and Hydrilla verticillata, some of which are also exotic to South America. Representatives of the Hydrocharitaceae family are also global invaders, with impacts on various ecosystems. Despite their ecological importance, aquatic macrophytes have characteristics that facilitate their rapid dispersal and reproduction, making some species invasive, with negative impacts on aquatic biodiversity. Accurate identification of these species is crucial, and molecular markers offer a powerful tool for aiding and understanding biological and ecological characteristics, such as reproductive strategies, means of dispersal and metapopulation dynamics. Chloroplastidial DNA (cpDNA) and nuclear ribosomal DNA (nrDNA) markers are widely used, and emerging techniques such as environmental DNA (eDNA) have shown great promise in studies with these organisms. For the development of this research, populations of H. coronarium introduced into Brazil were genetically characterized, contributing to the understanding of the phylogeographic processes involved in the invasion and providing the first genetic data of the species in South America. In addition, the invasive species Elodea canadensis was identified in eDNA samples collected from a lake in Berlin, using target DNA amplification with a species-specific primer, as well as evaluating the use of metabarcoding data to identify invasive species of aquatic macrophytes. The results obtained from the use of molecular techniques in the study of invasive aquatic macrophytes demonstrate an approach to biodiversity conservation.