eDNA Insights
In today's world, where habitat quality and biodiversity are under threat from climate change, intensive land use, and urbanisation, it's crucial to monitor the effectiveness of our efforts to restore ecosystems, such as the local gullies and stream catchments. At our recent Predator Free Tamahere community meeting, we were very fortunate to have Dr. Ang McGaughran from the University of Waikato share her expertise on monitoring habitat quality and biodiversity.
Community Hall Discussion with Dr. McGaughran, Photo Credit: Amanda Banks
Dr McGaughran explained that traditional methods of tracking biodiversity, like studying specific indicator species, have their drawbacks—they're time-consuming, costly, and often fail to provide a complete picture of ecosystems. But a new technology called environmental DNA (eDNA) offers a lot of potential.
eDNA allows us to study genetic material in the environment, giving us a better understanding of ecosystem health. By examining the genetic fingerprints left behind by organisms, we can track how the environment is faring over time. For instance, areas stressed by pollution or human activity may only be able support certain plants and animals or invasive species, while healthier areas boast greater biodiversity. By studying this, we can learn a lot about the environment's health and the challenges it faces.
In a recent study in New Zealand, researchers used eDNA to assess the health of rivers and streams nationwide. They developed a tool called a taxonomy-independent community index (TICI), which measures a river's ecosystem health based on eDNA samples from various locations. The results aligned well with other methods of measuring river health, demonstrating eDNA's potential as a valuable tool for conservation efforts. The study also emphasised the importance of considering upstream activities, such as urban development and land uses, which can impact river or stream health and eDNA results.
Image: local eDNA Testing Sites Map, photo credit: Dr McGaughran
Dr. McGaughran also discussed the 2015 and 2023 TICI results from our local streams, highlighting that despite ongoing restoration and predator control efforts, the streams' 2023 TICI ratings remained poor, indicating more work is needed.. However, there is something to be hopeful about: compared to 2015, the more recent ratings from 2023 are tantalisingly close to reaching 90, an "average" rating, suggesting that our continued efforts may soon yield positive outcomes.
TICI Results from local eDNA Samples, photo credit: Dr McGaughran
However, eDNA does have limitations, including false positives and false negatives. For example, in Tamahere, no long-tailed bat DNA was detected in the stream samples, despite their known presence in the gullies. Research is ongoing into methods that capture DNA from air, insects, or even spider-webs to provide a more comprehensive picture and improve detection of species that might not show up in a stream water sample.
Looking ahead, eDNA technology can provide vital information to help monitor and restore ecosystems effectively. This enables us to work smarter in protecting our environment for future generations.
A heartfelt thank you to Dr. McGaughran for sharing her valuable insights with our community!
