An Intro to eDNA and its Potential in Conservation Science.

Source: https://fishbio.com/technology/environmental-dna/

“The question is, are we happy to suppose that our grandchild may never be able to see an elephant except in a picture book?” — David Attenborough

From endangered tigers to fragile coral reefs, the task of conserving flora and fauna has never been more urgent. Conservation is the careful protection and management of nature, aiming to prevent plants, animals, and ecosystems from disappearing. It is not merely about preserving natural resources but represents a commitment to ensuring that future generations inherit a thriving, biodiverse planet. Among the various branches of conservation, species conservation plays a critical role. This pillar is dedicated to preventing extinction and aiding the recovery of threatened or endangered species. Conservationists employ strategies such as developing species-specific management plans, implementing captive breeding and reintroduction programs through translocations, and creating wildlife corridors to restore and sustain populations.

A key component of these efforts is effective species monitoring, which provides critical data to guide conservation actions. This can be achieved through visual observation, the use of trackers like GPS collars, and increasingly through environmental DNA (eDNA). eDNA, by analyzing genetic material shed by organisms into their surroundings, is transforming species monitoring, offering a non-invasive, scalable, and efficient way to assess biodiversity and track population changes across habitats. Its ability to monitor rare and elusive species and evaluate ecosystem health makes it a cornerstone of modern conservation science. Modern conservation efforts require the integration of technologies such as eDNA, AI-driven sensors, remote sensing, and computational modeling to revolutionize how species populations and habitat conditions are tracked. These tools can provide real-time data, offering valuable insights into environmental changes and enabling conservationists to act proactively rather than reactively. Platforms, like EarthRanger, which utilize data inputs from rangers combined with GPS data enable the swift detection of threats such as poaching or habitat degradation, allowing rangers to address issues before they escalate.

While these technologies could assist conservation efforts in unimaginable ways, implementing them on a large scale comes with obstacles. High initial costs, technical expertise requirements, and the need for reliable infrastructure — such as internet connectivity or permanent research bases — are barriers, particularly in remote or resource-limited areas. Overcoming the barriers to adopting these tools requires collaboration among governments, non-profits, and technology developers to create accessible, adaptable solutions suitable for diverse ecological contexts. By addressing these challenges, conservationists can leverage automation and advanced analytics to safeguard natural resources more effectively.

This article explores the emerging potential and challenges for eDNA to revolutionize species conservation. By analyzing genetic material shed by organisms into their environments, eDNA innovates in monitoring and protecting biodiversity. Its applications range from detecting species to assessing ecosystem health and tracking changes in population dynamics over time. eDNA is particularly transformative in aquatic environments, where traditional monitoring is labor-intensive and less precise. It also enables rapid biodiversity assessments in remote or inaccessible areas, supporting habitat restoration efforts and aiding in the early detection of invasive species. These capabilities offer immense opportunities to enhance conservation strategies, ensuring the survival of species and safeguarding the future of biodiversity.

Introduction to eDNA

Environmental DNA (eDNA) is genetic material released by organisms into their surroundings through biological secretions like skin cells, feces, urine, or mucus/saliva. This DNA can persist in various environments, including soil, water, or sediment. Analyzing eDNA allows researchers to detect the presence of organisms without directly observing or capturing them. Two key methods used in eDNA analysis are barcoding and metabarcoding. Barcoding targets a specific genetic marker to identify a single species, while metabarcoding uses universal primers to analyze genetic material from multiple species, providing a broader view of biodiversity.

Transforming Biodiversity Monitoring with eDNA Environmental DNA (eDNA) helps scientists monitor biodiversity in seven simple steps: (1) All living things leave DNA traces in their environment, like soil or water. (2) These traces are collected through sample gathering. (3) In the lab, DNA is extracted from the samples. (4) The DNA is then amplified using PCR. (5) Amplified DNA is sequenced to reveal genetic information. (6) Bioinformatics identifies species and measures diversity. (7) Finally, results are displayed on a platform showing biodiversity trends and metrics, helping track and protect ecosystems. Source: https://www.naturemetrics.com/knowledge-hub/edna

1. Collection: The process of eDNA analysis begins with collecting environmental samples, such as water, soil, or sediment. For water samples, researchers use sterile bottles to gather large volumes, which are then filtered on-site using fine filters to capture DNA fragments. For soil or sediment, samples are collected with sterile tools and carefully stored to prevent DNA degradation. In order to get accurate results, it is important to use proper collection and storage to avoid contamination which can compromise the quality of eDNA.

2. Preservation: Environmental DNA is highly sensitive to factors like UV radiation, temperature, and microbial activity, all of which can degrade genetic material. To preserve DNA integrity, samples are either frozen immediately or treated with special preservation buffers. These measures ensure that the eDNA remains intact long enough for further analysis, especially during transportation from remote locations to laboratories.

3. Extraction: Once the samples are preserved, DNA is extracted through chemical or mechanical methods. This process breaks open cells to release DNA while removing impurities such as proteins, lipids, or other contaminants.

4. Amplification: Because eDNA is often fragmented and present in small quantities, amplification is necessary to detect genetic material. This is achieved through Polymerase Chain Reaction (PCR), a widely used method for replicating DNA. PCR utilizes primers that bind to specific DNA regions, targeting either a single species (as in eDNA barcoding) or broader taxonomic groups (as in eDNA metabarcoding). Please see table for a description of primers. For barcoding, the primers are designed to amplify a known genetic marker unique to the species of interest, making it ideal for targeted studies. In contrast, metabarcoding employs “universal primers” that amplify genetic regions shared across many species, enabling the study of entire communities. Advanced methods like quantitative PCR (qPCR) and digital droplet PCR (ddPCR) can also quantify the DNA present in a sample, providing deeper insights into species abundance.

Table of different Primer types

5. Sequencing: The amplified DNA is then sequenced to identify the DNA. The choice of sequencing method depends on the scope of the study. For eDNA barcoding, where the target species is already known, Sanger sequencing is often sufficient for analyzing specific DNA fragments. However, eDNA metabarcoding relies on Next-Generation Sequencing (NGS) to process millions of DNA fragments simultaneously. This high-throughput approach is essential for creating biodiversity profiles, as it can identify multiple species within a single sample by analyzing amplified genetic markers. By combining amplification with sequencing, researchers can either confirm the presence of a specific species or gain a comprehensive understanding of ecosystem diversity.

6. Bioinformatics: Turning Data into Insights After sequencing the DNA, the next critical step is to analyze the resulting data through bioinformatics to gather additional insights beyond species identification, including for example community composition, population dynamics, habitat health, presence of invasive species or pathogens, and genetic lineage insights like diversity. This process involves comparing the raw DNA sequences obtained from eDNA samples to reference databases like GenBank or the Barcode of Life Data System (BOLD), which contain genetic data for a wide variety of known species. Bioinformatics tools, such as BLAST (Basic Local Alignment Search Tool), are used to align these sequences against the reference database to identify species. BLAST compares the similarity between the sequenced fragments (also known as “reads”) and database entries, with a higher percentage of similarity indicating a more confident match to a particular species. These tools also perform essential quality control by filtering out contaminant sequences and ensuring that closely related species are differentiated based on unique genetic markers. Furthermore, with metabarcoding, a large number of species can be identified simultaneously from a single environmental sample. By grouping DNA sequences into clusters (Operational Taxonomic Units or Amplicon Sequence Variants) based on their similarity, bioinformatic pipelines can identify the diversity of organisms present in the sample and estimate their relative abundance. The insights gained from this data can help researchers understand biodiversity patterns, monitor endangered species, and even track environmental changes. Thus, bioinformatics plays a central role in transforming raw eDNA data into valuable conservation insights, enhancing the ability to monitor ecosystems without direct observation.

Table of advantages and challenges of eDNA

The use of eDNA and genomics is revolutionising species monitoring and conservation by enabling non-invasive, efficient tracking of biodiversity in various ecosystems. eDNA technologies allow researchers to detect species presence, abundance, and movement patterns through DNA traces left in water, soil, or air, making it possible to monitor elusive or endangered species without direct observation. Genomics complements this by providing insights into genetic diversity, population health, and adaptive traits, which are critical for understanding species’ resilience to environmental changes. Academic institutions like Stanford, UC Santa Cruz, and the University of Copenhagen are advancing eDNA and genomic research, developing new methods for analyzing biodiversity at scale. Meanwhile, companies like NatureMetrics and Illumina are driving innovation by creating accessible sequencing technologies and AI-powered analytics platforms.

Despite its transformative potential, the use of eDNA and genomics in species conservation faces significant challenges. First, field sampling must be rapid, accurate, and conducted to high standards to preserve the integrity of DNA, which degrades quickly in the environment, making timely processing and analysis crucial. Second, reference databases remain limited, requiring broader inclusion of species identifiers and key genes of interest, e.g. those linked to climate resilience traits like temperature or drought resistance. Finally, while computing power, AI, and machine learning hold immense promise for extracting insights and predictive modeling, these tools are still in the early stages of effectively leveraging the vast and complex datasets generated by eDNA and genomics. Addressing these challenges will be critical to unlocking the full potential of these technologies for conservation science.

Spotlight Current Companies

Two current companies focused on these challenges and presenting solutions are Limelight Rainforest and Spygen.

Limelight Rainforest

Limelight Rainforest is an interdisciplinary team recognized for its innovative contributions to biodiversity monitoring using eDNA and advanced technology. Their work gained significant attention after winning the $5 million XPRIZE Rainforest competition, where they showcased tools like drone-deployed canopy rafts equipped with cameras, microphones, and light traps for DNA sampling. Additionally, they utilized machine learning to classify species and robotics for collecting leaf and water samples for eDNA analysis. The team combines expertise from ecologists, Indigenous scientists, and engineers to develop scalable tools aimed at rainforest monitoring and conservation. Their solutions align with global biodiversity goals, emphasizing technological accessibility for ecosystem protection.

Limelight Drone used for sampling a body of water. Source:https://news.njit.edu/njit-professor-advances-finals-10m-xprize-rainforest-competition

Spygen

Spygen is a French company specializing in environmental DNA (eDNA) applications for biodiversity assessment. They provide services to detect and monitor species in aquatic and terrestrial environments using eDNA from water, soil, or air samples. Their approach includes advanced DNA barcoding and metabarcoding techniques, enabling efficient species identification without direct observation. Spygen collaborates with conservation organizations, research institutions, and governments worldwide to support biodiversity preservation and environmental management initiatives. Their work emphasizes accuracy in species detection and offers an invaluable tool for conservationists working to understand and protect ecosystems

Water sampling for eDNA analysis. Source: https://www.tereo-eren.fr/a-decouverte-de-ladn-environnemental-spygen/

Conclusion

The future of environmental DNA (eDNA) holds incredible potential as it converges with cutting-edge technologies like machine learning, predictive modeling, and integrated data analysis. By combining eDNA analysis with machine learning algorithms, researchers can uncover patterns in biodiversity that are not immediately visible, enabling more accurate predictions of species distributions and responses to environmental changes. When paired with other data sources, such as remote sensing, climate models, and historical ecological records, eDNA has the potential to provide a comprehensive view of ecosystems, enhancing our ability to detect early signs of environmental stress. Predictive modeling can use these data layers to simulate scenarios, helping conservationists anticipate challenges like habitat shifts, invasive species spread, and population declines. As technologies continue to advance, eDNA stands as a cornerstone of global conservation efforts.