How can environmental DNA methods be useful for understanding “who lives where, and when”?

Author: Molly Czachur

There’s a whole world of biodiversity out there, and there are global efforts to measure species distributions so that we can make informed management decisions. This could be for environmental reporting, impact assessments or otherwise. You could be a local environmental group who want to measure biodiversity regularly or track the impact of human activity. Whatever your reason for wanting to know what’s out there, we are often limited by using methods where we need to see or even catch the target organisms in order to describe them.

What if we didn’t even need to see the animals that we are looking for?

All living things leave a trace of DNA in the environment. Slimy fish leave a nice trail of DNA in the water as they swim, and this DNA comes from their mucus, scales and even faeces. Mammals shed DNA into the environment too, maybe from pieces of hair, cells, skin and also faeces. Birds do the same, and humans, insects, amphibians, reptiles and all other living things. The environment is one big soup of environmental DNA or eDNA.

For biodiversity monitoring, you could take advantage of the eDNA that exists in your study site. You can collect a cup of water, a spoonful or soil or even a net full of pollen from the air, and discover the biodiversity of that area for that moment in time.

Your eDNA samples will contain complex biological information, including many species from many different taxonomic groups. We can generate large datasets that give you an overview of the biodiversity in your sample. This total community-level assessment is usually impossible in many real-world applications, so these traces of eDNA are opening up a whole new world of monitoring in nature.

How easy is it to do? For aquatic monitoring, it’s as simple as collecting water and filtering it through the NatureMetrics filtering kit. It’s designed to be as universal as possible- the kit is a simple filter and syringe, so anybody can collect and filter their chosen waterbody. The genetic material is trapped in the filter, so you send the filter back to our lab and we’ll extract the DNA and tell you what you’ve found.

With traditional methods, you can spend lots of money and not necessarily get a complete picture of what’s living at your site. Take advantage of eDNA methods and gain larger and more complete biodiversity datasets. The tools offer higher detection at far higher throughput rates, with results that are consistent and accurate. This makes the results easy to standardise, share between groups, and repeat throughout the year. Contemporary eDNA data will allow you to catch exciting biodiversity trends in your site. Are you seeing declines in key indicator species, can you see a loss of species diversity after a large impact on your site? Spend less time sampling and more time interpreting your up-to-date and representative results.

We’ve worked on a huge range of taxonomic groups in lots of different ecosystems. An example of one of our fish projects comes from the River Frome in England, where we measured the fish communities at different areas along the river. We sampled the river mouth, the saline transition zone and also in upstream and purely freshwater areas. This is a typical example of using our eDNA methods in a range of salinities to achieve a biodiversity assessment. Some fish were found in all sites, and others were found only in certain areas. We could use this to inform our collaborative project with Natural England.

We’ve also got strong citizen science opportunities, and we believe that anybody can sample eDNA and find out what’s living in their chosen area. We took part in Chris Packham’s BioBlitz in Wicken Fen, and the volunteers did a great job. They collected water samples, filtered them, then we took them back to the labs for processing. They detected 12 fish species in their samples (and a toad!). The Environmental Agency has been monitoring this area since 1984, and they have found the same species, but they have never found them all in a single survey. Our non-experts demonstrated just how sensitive and powerful the eDNA methods can be.

The future of eDNA technology is bright, especially for environmental reporting and assessments. We can set baselines quickly and affordably, which means you can measure species across space and time. We can also monitor habitat restorations, unravel ecosystem interactions on a regular basis, and we can use this as a powerful monitoring tool to hold people accountable for the impact that they are having on the natural world. This tool is also perfect for people to show that they’re doing good for the environment, so it works both ways.

NatureMetrics is bridging the gap between the commercial sector and the exciting academic advancements that are already happening with eDNA research. If you have a niche that you want to explore with eDNA, get in touch to see how we can assist you.

This blogpost was based on our experiences of eDNA projects, some of which you can access on our case studies page. It was also inspired by a recent podcast where Scott Poynton interviewed NatureMetrics CEO, Dr. Kat Bruce. You can listen to the full podcast below.