Innovative Uses of Environmental DNA in Conservation Efforts
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Chapter 1: Introduction to Environmental DNA
Biodiversity is increasingly under threat, leading to the extinction of numerous species. This decline is alarming since our well-being is closely tied to the diversity of life around us (further reading: The Importance of Biodiversity for Human Health). To address this issue, we need to adopt more sustainable practices and actively engage in environmental protection. However, effective change can only stem from a deep understanding of the current environmental challenges.
To gain insights into these challenges, various methodologies are employed. For instance, remote sensing utilizes sensors to gather environmental data, assessing plant health (further reading: The Role of Remote Sensing in Environmental Monitoring). Additionally, animal behavior serves as a biomarker for studying pollution levels (further reading: How Animal Behavior Reflects Environmental Health). Another promising approach is studying environmental DNA, or eDNA. This genetic material, present in all living organisms, can reveal the presence or absence of specific species within ecosystems.
Environmental DNA comprises traces left by plants and animals in their surroundings. For example, as humans move through different environments, we naturally shed hair and skin cells, both of which contain DNA. Despite their small size, these remnants can provide sufficient genetic material to monitor biodiversity in an area. Notably, a single human cell can contain up to 2 meters (6.6 feet) of DNA! This genetic material can also be sourced from feces, urine, mucus, blood, and decaying organisms.
Employing eDNA as a tool for assessing environmental health is advantageous for several reasons:
- It is a non-invasive technique, unlike remote sensing, which may require the installation of devices that can disturb local ecosystems.
- eDNA detection does not necessitate the physical presence of organisms, which is a limitation in biomarker approaches.
- This methodology is adaptable to various ecosystems, including aquatic environments and harsh climates like the Arctic.
- Samples can be collected autonomously, even by robots, without needing expert supervision.
- Analysis can be conducted by non-specialists, significantly reducing costs and increasing efficiency.
- eDNA is precise, allowing for the identification of multiple species from a single sample.
Before drawing conclusions that influence conservation efforts, a series of steps must be followed. Below, we outline the process of eDNA analysis and its role in biodiversity conservation:
Section 1.1: Sampling
The initial phase in eDNA analysis involves collecting environmental samples. For example, a small water sample from a lake can yield a substantial amount of genetic material for examination.
Section 1.2: Extraction
The next step is to extract DNA from the collected samples. This can be achieved through various methods:
- Filtration: The most widely used technique, where filters capture DNA.
- Precipitation: Suitable for small water volumes, involving the addition of substances like ethanol to help DNA settle.
- Centrifugation: Also for small samples, this method spins the water, causing DNA to collect at the container's edge.
After extraction, the eDNA can be preserved through freezing or by using specialized solutions.
Chapter 2: Barcoding and Identification
The third stage involves barcoding, which entails reading the DNA fragments from the samples. This process allows for the identification of individual species or multiple species through a method known as eDNA metabarcoding.
For single species identification, the polymerase chain reaction (PCR) is employed to amplify DNA fragments, making them detectable. Real-time PCR, a computerized version of this process, enhances efficiency. This video provides further insights into how PCR and real-time PCR function:
In the case of multiple species identification, PCR is again utilized to copy a large set of gene fragments simultaneously. This approach not only identifies various species but also sheds light on community dynamics, which refers to changes in the composition and structure of biological communities over time. These dynamics can be influenced by natural events like volcanic eruptions or human-induced factors such as climate change.
Section 2.1: DNA Identification
The fourth phase focuses on identifying the DNA source, which is facilitated by comparing sample data against publicly accessible reference databases. These databases continue to expand, improving the accuracy of species identification over time.
For instance, the genetic sequence of a goldfish is stored in the MitoFish database, allowing researchers to pinpoint its identity when its DNA is found in a sample.
Section 2.2: Analysis
The fifth step involves analyzing the identified DNA using various statistical models. These analyses help to elucidate the biodiversity present in the sampled area. Commonly employed models include:
- eDNA concentration models: These assess the relationship between DNA generation and decay to estimate species populations.
- Quantitative biomass estimation models: These evaluate the amount of DNA in a sample to gauge species numbers.
- Spatiotemporal distribution prediction models: These help understand the habitat and seasonal patterns of different species.
Section 2.3: Conservation Strategy
The final step in eDNA analysis is to formulate a biodiversity conservation strategy based on the findings. For instance:
- If an invasive species is detected, a strategy can be developed to mitigate its impact.
- If a species' population is nearing extinction, measures can be implemented to protect it.
- Upon identifying a harmful pathogen, strategies can be created to prevent its spread.
- If a population is found to be declining, potential causes can be investigated and addressed.
Together, these strategies can significantly impact biodiversity conservation efforts.
Conclusion
In summary, environmental DNA research plays a vital role in shaping biodiversity conservation strategies through a systematic process: sampling, extraction, barcoding, identification, analysis, and strategy formulation.
How You Can Contribute
Here are practical steps you can take to assist in biodiversity conservation:
- Properly dispose of waste to prevent environmental contamination.
- Choose organic products whenever possible.
- Reduce your ecological footprint by adopting sustainable travel practices and minimizing waste and water usage.
- Relocate insects instead of exterminating them.
Which of these practices can you incorporate into your daily life? Do you have other suggestions for enhancing biodiversity conservation? Your ideas could inspire others—please share them in the comments!
Credit
This article is based on:
Sahu, A., Kumar, N., Singh, C. P., & Singh, M. (2022). Environmental DNA (eDNA): Powerful Technique for Biodiversity Conservation. Journal for Nature Conservation, 126325.
The second video titled "Alice Valentini: eDNA for Aquatic Biodiversity" explores how eDNA can be utilized to understand aquatic ecosystems and their biodiversity, providing further insights into this vital conservation tool.