The presence of threatened and endangered species on military lands can place restrictions on use of lands for readiness training. To avoid conflicts with mission readiness and natural resource management, the Department of Defense actively monitors populations of listed and at-risk species. However, many aquatic species pose unique challenges for monitoring due to the difficulty of thoroughly surveying aquatic environments. Current technologies for detection of aquatic species may have low detection probabilities, require high inputs of field time of taxonomically-trained technicians, and/or disturb aquatic habitats. The detection of DNA in the aquatic environment is a recently developed technique for detecting aquatic vertebrate species that has demonstrated potential for avoiding these problems.
Environmental DNA can be used to detect any animal or plant with a significant aquatic stage, but is best applied to species that are difficult to detect using conventional survey methods. The technology could thus be deployed at any DoD site with sensitive or invasive aquatic species that are rare or elusive.
For hard-to-detect species, including many amphibians, fishes, and invertebrates, lack of reliable monitoring data can lead to an underestimate of the species’ distribution. Accurate information about the locations of aquatic animals and plants is needed to effectively and efficiently manage these populations and their habitat, prevent constraints on military training, and reduce the potential for listing of at-risk species under the Endangered Species Act (ESA). Environmental DNA provides a technique for detecting aquatic species that can improve monitoring programs by lowering costs, reducing impacts to sensitive species, and improving the quality of data produced.
Using eDNA in detection and monitoring programs for aquatic species allows DoD managers to implement endangered species management plans efficiently, reliably, and with minimal impacts to sensitive species. The sensitivity of eDNA methods for detecting aquatic organisms, even at very low densities, also makes them a powerful tool for early detection of invasive species. For species where sampling is destructive to the target organism, managers may want to replace standard surveys with eDNA surveys; for species that are sometimes non-invasively and easily directly observed, eDNA may better serve as a supplementary technique, with samples collected only from sites where the target species is not detected through other means (e.g., visual surveys).