Steps forward in biomonitoring 2.0: eDNA Metabarcoding and community-level modelling allow the assessment of complex drivers of Neotropical fish diversity.

Abstract

The way we inventory and monitor biodiversity globally has been revolutionized by new molecular and ecological methods (Pawlowski et al 2021). Nonetheless, the Neotropical realm still represents a great challenge to our understanding of species distribution patterns and the role played by different drivers of biodiversity. The paper by Coutant et al. (2022) is a great advance towards a holistic approach to quantifying the contribution of environmental and anthropogenic factors that drive community assembly in the Amazon, and how we can apply such knowledge to guide future monitoring programmes. Disentangling the relative roles played by multiple drivers of biodiversity allowed them to also highlight hotspot areas hosting unique freshwater fish diversity and to pinpoint conservation priorities. Toward this end, the authors applied an innovative framework that included the use of environmental DNA (eDNA) to conduct fish inventories combined with community-level modelling. Their multifaceted approach accounting for taxonomic and functional measures of biodiversity allowed a thorough evaluation of ecological patterns. They reported a mismatch between functional and taxonomic biodiversity in their responses to geographical, environmental, and anthropogenic factors. Functional diversity was influenced by environmental and anthropogenic factors, while fish taxonomic diversity was determined by dispersal restrictions at both intra and inter-basin scales in the Guiana Shield. The role played by dispersal limitation and human activities in shaping fish diversity in large rivers is very relevant considering that Amazonian freshwater ecosystems are facing large-scale degradation due to human activities greatly impairing river connectivity (Castello & Macedo, 2016).