Can Environmental DNA (eDNA) help us improve biodiversity?

At this point, hearing statements like the one above is startlingly commonplace. So, it should be no shock that the United Nations calls the loss of our biodiversity a pressing global emergency.

The alarming statistics pertaining to these matters are almost ceaseless. For instance, 1 million out of 8 million animal and plant species face extinction. Wild vertebrates have dropped by nearly 70% on average in the past 50 years. Also, wild insect species abundance has halved.

Furthermore, an unprecedented degradation rate plagues our ecosystems, impacting plant and animal species’ ability to support their own well-being.

These issues are all expected to exacerbate and accelerate as time passes.

However, it doesn’t have to be too late.

Focusing on solutions and innovations can change the course we’re on. One such innovation is Environmental DNA (eDNA). Read on as we further discuss the importance of biodiversity and how eDNA can make a significant big-picture impact.

The broader importance of robust biodiversity

Almost all aspects of our lives are touched and affected by biodiversity. From utilitarian to intrinsic, humans have many reasons to value this omnipresent component of mother nature. We appreciate what it does for us while cherishing what it does, is, and has independent of us.

Biodiversity’s utilitarian–or practical/useful–values to humans include food, shelter, fuel, and medicine. They also include seed dispersal, climate regulation, pollination, nutrient cycling, water purification, and agricultural pest control.

An unprecedented degradation rate plagues our ecosystems, impacting plant and animal species’ ability to support their own well-being.

Cultural components of the human experience also benefit from biodiversity, such as our spiritual or religious inclinations.

The inherent or intrinsic worth of biodiversity is more philosophical. It more or less refers to the unassailable right it has to exist.

Another essential reason to value biodiversity is its inherent connection to our identity. It can impact our social norms and relationships with others. This line of thinking extends to our responsibility for the environment and its well-being.

Primarily, humans discuss the varying ways we appreciate biodiversity because it can help shift the conversation and improve upon the path we’re currently on.

Productive discussions about biodiversity can help yield solutions–or, at least, provide a heady impetus to make a difference. On that note, part of the biodiversity discussion has begun to revolve around Environmental DNA.

What is Environmental DNA?

Deoxyribonucleic acid (DNA) is an organism's hereditary material. It possesses the biological instructions necessary to build and maintain the organisms. DNA’s chemical structure is mirrored in all organisms, but variances exist in the DNA building blocks’ sequencing.

Building blocks of DNA are known as “base pairs”. Unique sequences of these pairs (namely, recurring patterns) help identify populations, species, and individuals.

Environmental DNA is released into the environment from an organism. It’s nuclear or mitochondrial in makeup. Secreted faeces, gametes, hair, shed skin, and carcasses are all eDNA sources.

Extracellular (dissolved DNA) and cellular eDNA forms can be detected. eDNA–in aquatic settings–is distributed by currents and other hydrological processes after being diluted. Depending on environmental conditions, it only lasts between 7 and 21 days.

UVB radiation exposure and exposure to heat, acidity, and endo/exonucleases may degrade eDNA.

A poignant snapshot of an ecosystem’s health (and its species’ health) can be ascertained by studying eDNA.

How Is eDNA being used to help biodiversity?

There’s plenty of information to be gleaned about our ecosystems when you analyse the water. After all, water is rich with animal DNA via hair, faeces, saliva and skin.

A poignant snapshot of an ecosystem’s health (and its species’ health) can be ascertained by studying eDNA.

Here’s how environmental DNA has been taking significant leaps in wildlife monitoring:

Extracting valuable information straight from the source

Wild animals traverse their habitats and leave genetic markers behind. These traces are washed into rivers, streams, lakes, and other bodies of water. Scientists collect and filter water samples, capturing organic materials rich in eDNA. These are delivered to a lab, where they’re processed.

Scientists can leverage eDNA to detect pathogens that harm landscapes. It can also help discover endangered species while tracking climate change’s impacts.

Discovering what’s within

All individual eDNA samples possess dozens–if not hundreds–of genetic codes for animals. This information presents crucial evidence about the overall health of the terrestrial and aquatic ecosystems.

Scientists can leverage eDNA to detect pathogens that harm landscapes. It can also help discover endangered species while tracking climate change’s impacts.

Making sense of it all

Amplifying and sequencing DNA in the lab enables researchers to detect the exact species found in a given sample. This process can get precise enough that individual animals can be detected. Every single living being really does matter when it comes to biodiversity and preservation.

The meat of the matter

An animal’s age or the population size of a species can’t yet be determined by eDNA. However, combining eDNA with other tools can bolster scientists’ proficiency in assessing wildlife populations and habitat statuses. Thus, experts and specialists in the space can approach conversation strategies about biodiversity in a more timely and impactful fashion.

Other talking points about eDNA

Scientists from the World Wildlife Fund (WWF) will soon conduct a survey in Bhutan’s Royal Manas National Park, combining eDNA with camera traps to study tigers and their prey.

The hope is that both methods generate similar results, meaning eDNA sampling could work part-and-parcel with camera traps in pending national tiger surveys. This will vastly decrease costs.

Such work is especially relevant due to the endangered status of tigers and the role such a large predator plays in robust, thriving, and biodiverse ecosystems.

On a similar note, eDNA sampling–in certain instances–outperforms other monitoring methods in speed and comprehensiveness. One WWF study in British Columbia found that–compared to camera trapping–eDNA stream water sampling detected 25% more terrestrial mammals. This superior performance stemmed from some species (e.g., several bat species) not being big enough to trigger camera activity.

Innovation and forward thinking will be keys to improving biodiversity

Biodiversity is a crucial element of our existence and is under constant threat. Genetic diversity is what saves a species from dramatic perturbations in the environment such as climate change. As an example of innovation in the conservation field, the Frozen Ark Projectcharity cryopreserves the gametes, DNA and stem cells of animals on the ‘endangered (Red) list’. The gametes can be used to increase genetic diversity in small endangered breeding populations / programmes and the DNA supplies the blueprint of species on the edge of extinction. With tools like eDNA, systematic cryopreservation of gametes and a continued focus on similar innovations and problem-solving, we’re more likely to correct the course of environmental destruction and help contribute to robust, sustainable, diverse ecosystems.