image: Locations of 59 lakes sampled for sedimentary DNA analysis, overlaid on a vegetation map of the Tibetan Plateau. Ⅰ, needleleaf forest; Ⅱ, needleleaf and broadleaf mixed forest; Ⅲ, broadleaf forest; Ⅳ, scrub; Ⅴ, desert; Ⅵ, steppe; Ⅶ, grass-forb community; Ⅷ, meadow; Ⅸ, marsh; Ⅹ, alpine vegetation; Ⅺ, cultivated vegetation; Ⅻ, land without vegetation.
Credit: ©Science China Press
A recent study led by Dr. Li from Zhejiang Normal University, in collaboration with international researchers, reveals the potential of plant DNA metabarcoding for monitoring plant compositions on the Tibetan Plateau (TP). The study, published in Science China Earth Sciences, highlights the advantages of sedimentary DNA (sedDNA) extracted from lake sediments over traditional pollen analysis, providing a more detailed and localized perspective on vegetation monitoring and reconstruction.
The study involved the surface sediments from 59 small lakes and ponds located in the southwestern Tibetan Plateau. Using plant DNA metabarcoding, the researchers identified 186 terrestrial plant taxa, with 30.1% of them identified to the species level. In comparison, traditional pollen analysis identified only 75 plant taxa, with just 5.3% identified at the species level. The results indicate that plant DNA metabarcoding captured a significantly higher number of taxa and achieved a greater taxonomic resolution than pollen analysis, especially for herbaceous taxa such as Asteraceae, Poaceae, and Cyperaceae.
“Our findings underscore the utility of plant DNA metabarcoding in accurately reflecting the vegetation composition in the immediate vicinity of lakes, offering a more precise method for vegetation monitoring,” said Dr. Li, lead author of the study. “This method not only improves our understanding of current biodiversity but also provides valuable insights into ecosystem dynamics in regions where conventional fieldwork is difficult.”
The team also found that while pollen analysis captures many regional signals, sedDNA primarily reflects very local plants at the community level. This distinction emphasizes the complementary nature of the two methods, with sedDNA offering superior resolution for local vegetation studies and pollen analysis remaining valuable for regional vegetation reconstructions.
Despite its advantages, the researchers acknowledged limitations in the sedDNA approach, such as the challenges of amplifying DNA from closely related species and the incompleteness of modern reference database. To address these issues, the authors suggest the use of multiple primers and the development of region-specific DNA reference database to enhance the accuracy and applicability of plant DNA metabarcoding.
The study’s findings have significant implications for biodiversity conservation, climate change research, and ecosystem monitoring. As climate change continues to alter environmental conditions on the Tibetan Plateau, understanding shifts in vegetation composition will be essential for assessing ecosystem resilience and biodiversity. Additionally, plant DNA metabarcoding could play a key role in long-term ecological studies, enabling researchers to track changes in vegetation over time and providing a more comprehensive approach to palaeo-ecological research.
See the article:
Wu K, Li K, Jia W, Stoof-Leichsenring K R, Herzschuh U, Ni J, Liao M, Tian F. 2024. Application of plant DNA metabarcoding of lake sediments for monitoring vegetation compositions on the Tibetan Plateau. Science China Earth Sciences, 67(11): 3594–3609, https://doi.org/10.1007/s11430-023-1358-0
Journal
Science China Earth Sciences