Applications of Environmental DNA (eDNA) in Wildlife Monitoring and Biodiversity Conservation

Environmental DNA (eDNA) has emerged as a transformative molecular tool for biodiversity assessment, wildlife monitoring, and ecosystem conservation. Unlike conventional survey methods that rely on direct observation, trapping, or specimen collection, eDNA enables the detection of organisms through genetic material naturally released into environmental matrices such as water, soil, sediments, snow, and air. This non-invasive approach has significantly improved the efficiency, sensitivity, and cost-effectiveness of monitoring rare, elusive, endangered, and invasive species while minimizing disturbance to natural habitats. Recent advances in high-throughput sequencing, metabarcoding, quantitative polymerase chain reaction (qPCR), digital PCR (dPCR), and bioinformatics have substantially expanded the applications of eDNA in ecological research and conservation biology. Environmental DNA has become an indispensable tool for species inventory, habitat assessment, population monitoring, community structure analysis, invasive species surveillance, pathogen detection, and evaluation of ecosystem health across aquatic, terrestrial, and aerial ecosystems. Moreover, integration of eDNA with geographic information systems (GIS), remote sensing, artificial intelligence (AI), machine learning (ML), and ecological modelling has enhanced the accuracy and predictive capability of biodiversity assessments. Despite its considerable advantages, several technical challenges remain, including DNA degradation, environmental inhibition, contamination risks, incomplete reference databases, and limitations in quantitative interpretation. Standardization of sampling protocols, laboratory procedures, and bioinformatics pipelines is therefore essential for improving reproducibility and reliability. This review provides a comprehensive overview of the principles, methodologies, analytical approaches, and diverse applications of environmental DNA in wildlife monitoring and biodiversity conservation. Furthermore, recent technological developments, current limitations, future research priorities, and policy implications are critically discussed to highlight the expanding role of eDNA in supporting evidence-based conservation strategies and sustainable biodiversity management under changing global environmental conditions.