U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version



Piaggio, A.J. 2021. Environmental DNA for conservation. pgs 157-175. In: Wich, S.A., and A.K. Piel. editors. Conservation Technology. Oxford University Press, Oxford, United Kingdom.

doi: 10.1093/oso/9780198850243.003.0008


U.S. government work


Biodiversity must be documented before it can be conserved. However, it may be difficult to document species with few individuals (Thompson, 2013; Goldberg et al., 2016), thus it requires a multitude of tools to detect species that occur in low numbers or are elusive (see the various chapters in this volume). One tool that has become useful for conservation efforts utilizes environmental DNA, which is DNA shed into the environment by organisms (eDNA; Taberlet et al., 2018). Typically this involves taking environmental samples such as soil, water, air, or using biological surrogates for sampling biodiversity (e.g. leeches, sponges, carrion flies, etc.; Schnell et al., 2012; Calvignac-Spencer et al., 2013; Lynggaard et al., 2019; Mariani et al., 2019) and using laboratory approaches to concentrate, isolate, and test for target DNA through polymerase chain reaction (PCR) amplification (Taberlet et al., 2018). The utilization of eDNA for species detection is part of a larger field of non-invasive DNA sampling, which more broadly includes collecting DNA passively from wildlife, through collection of faeces, saliva, feathers, hair, or other methods of sampling shed DNA. Environmental DNA has been used to document presence/absence of a target species (Ficetola et al., 2008a, 2008b; Himter et al., 2017) or to quantify relative abundance for biodiversity from varied environments such as the arctic (e.g. Leduc et al., 2019; Von Duyke et al., 2019), marine (e.g. Port et al., 2016; Jo et al, 2017; Stoeckle et al., 2018), freshwater (e.g. Lacoursi^re-Roussel et al., 2016; Doi et al., 2017), and tropical (e.g. Schnell et al., 2012; Gogarten et al, 2020) ecosystems. The application of this technology includes the detection of invasive species, pathogens (including DNA and RNA), species of conservation concern, and biodiversity (Acevedo-Whitehouse et al., 2010; Rees et al., 2014; Sakai et al, 2019).

In this world -of 'fast-paced technological advances, not all new methods prove useful in an applied context. Although eDNA has not been used regularly in biodiversity conservation for more than a decade, it has proven to be an extremely practical and informative tool. The utility of eDNA is supported by ongoing advancements and development of novel applications. There is no easy way to standardize the application or methods of eDNA as the conservation question, and the target system must drive the selection of a range of options at every step. However, guidelines now exist for the best practices of optimizing a sampling scheme and sample processing for eDNA applications (Goldberg et al., 2016; Jeunen et al., 2019; Klymus et al., 2020; The eDNA Society, 2019; Shu et al, 2020). Further, the ranks of experienced eDNA practitioners have expanded globally; thus, it is fairly easy to find expert consultation. Therefore, it is now practical and prudent to adopt eDNA in the service of biodiversity conservation efforts.