Conclusions
In the context of global biodiversity decline where ecosystems are under heavy stress and subjected to rapid changes, it is critical to increase our knowledge of species interactions to support the restoration and conservation of ecosystems effectively, and in a non-invasive manner. Threats to species are often assessed in terms of habitat loss, overharvesting, or over-predation (Kerr & Deguise, 2004). Yet, populations may also decline through successive loss of species interactions (Valiente‐Banuet et al., 2015; Simmons et al., 2020) and studying a single species may limit our full understanding of the changes and threats to an entire ecosystem as species interaction involves multiple species together (Roslin & Majaneva, 2016). In fact, positive and negative interactions synergically work to maintain the stability, health, and function of an ecosystem. This thus demands a fast, reliable and non-invasive approach. Currently, eDNA-based methods exhibit accurate information about species-specificity, community dynamics and ecological networks. Although to date there remains a limited number of investigations using eDNA to critically assess and identify PAI, we propose eDNA methods to herald a revolutionary era for studying complex and cryptic ecological links in nature.