Have you ever heard of the term environmental DNA (eDNA)? This refers to DNA from animals that is found in the environment as a result of natural shedding. Think: dead skin, feces, fur, etc. When experts collect these eDNA samples, they can better understand the species present within that given ecosystem.

Many professionals use eDNA to study and research different animals and habitats. This helps them protect the animals’ overall well-being. 

Interested in learning more about eDNA and how it’s used in animal conservation? In this article, we speak with Dr. Steven Latta, Director of Conservation and Field Research at The National Aviary. In his own work, he collects eDNA samples from water, leaf litter, feathers, egg shells, and other substrates to identify species presence. Here’s what he shares about the topic.

What is eDNA?

eDNA is an affordable and efficient tool often used for animal conservation. Consisting of shed animal DNA, it helps scientists conduct more effective research and monitor ecosystems.

“eDNA is deoxyribonucleic acid that occurs in the environment (environmental DNA),” Dr. Latta explains. “DNA is the hereditary material that builds a living organism and ensures its functioning as a living being. Because the same four chemical compounds or nucleotide bases structure DNA across all organisms, and because that structure is hereditary, identifiable differences exist between all species in how those chemical compounds are ordered.”

As a result, eDNA allows researchers to detect and identify unique and even invasive species.

Where Does eDNA Originate?

The genetic material that is eDNA comes from skin cells, feces, hair, saliva, mucus, and other sources. These materials are shed by animals and released into the environment, where they become sources of eDNA. 

“Once introduced into the environment, eDNA can be distributed and diluted across aquatic or terrestrial environments,” says Dr. Latta. “For example, river currents or atmospheric conditions may distribute eDNA some distance from its source. However, eDNA will also be degraded as it encounters certain environmental conditions, including UV radiation, high acidity, microbial activity, and especially exposure to heat.”

Dr. Latta says that scientists typically collect eDNA from targeted aquatic environments, soil, or even air.

“Studies that are more specific may target a particular nesting or foraging site, a roost or hibernaculum, or almost any other ecological site where scientists or conservationists have questions about its use,” he adds.

He adds that some scientists have even collected spider webs and blood meals as eDNA samples.

How eDNA Protects the Animal Kingdom

eDNA serves a variety of purposes, according to Dr. Latta. In fact, many scientists and resource management communities use eDNA as a non-invasive tool for biodiversity assessments and species and habitat monitoring.

“The use of eDNA can be less time-consuming and less expensive than traditional field methods,” he explains. “This may be especially true in particular habitats. For example, in aquatic conditions where species are less visible and more difficult to sample, eDNA is an attractive alternative to traditional field methods. In such cases, eDNA may improve species inventories and biodiversity assessments.”

Latta adds that eDNA often helps scientists discover and identify rare microorganisms or other small invertebrates.

“When repeated at regular intervals, eDNA-based species assessments and inventories can help reveal changes in wildlife communities resulting from management efforts, environmental degradation, climate change, or other impacts, both positive and negative,” Dr. Latta continues. “These species assessments can also be used in an adaptive management scenario, to monitor the impacts managers may be having on species through habitat manipulations, habitat improvements, and habitat restoration efforts.”

eDNA has become a powerful animal conservation tool, especially when it comes to detecting rare or invasive species.

“For example, samples of river water have established the presence of extremely rare, native freshwater mussels in the Ohio River watershed of North America,” Latta explains.

“Invasive species have proven to be particularly devastating to native communities and ecosystems, so the detection, identification, and eradication of invasive species is of high importance,” he adds. “Once eradication efforts of invasives have been implemented, eDNA can be used to confirm the success of the eradication measures.”

Challenges of Monitoring Biodiversity

Like anything else, eDNA has some current limitations.

“Despite the likelihood of degradation of eDNA under particular conditions, in other conditions, eDNA may be preserved, so questions of when DNA was shed are common around the detection of rare species,” Dr. Latta says.

Though it might have its challenges and limitations, eDNA is still an invaluable option for scientists and conservationists alike.