Pressed plant specimens collected centuries ago and stored in herbaria around the world could play a key role in facilitating the tracking of genetic change and extinction risk in plants, a McGill University-led study indicates.
By analyzing more than 51 million digitized herbarium records, researchers found that historical collections could be used to reconstruct over 16,000 plant populations, spanning 41 thousand species and dating back more than 250 years. The findings suggest that herbaria offer scientists an unprecedented opportunity to monitor genetic diversity across much of the planet and establish long‑missing baselines for conservation.
"Humanity's vast trove of historical plant specimens offers an unparalleled view of population‑level genetic change through time," said Isaac Eckert, a PhD candidate in the Department of Biology and lead author of the study. "Extracting and sequencing the genetic data housed in our collections would transform our ability to detect and better understand the causes of genetic change."
Monitoring genetic change is increasingly recognized as essential for conservation, because declines in genetic diversity can reduce a species' ability to adapt and raise extinction risk, according to the researchers. Yet population-level genetic data required to monitor genetic change remain scarce for most plant species, particularly over long time spans.
To assess whether herbaria could fill that gap, the research team developed a method to assemble specimens into historical plant populations using information such as location, collection date and species life history traits. Their results show that existing digitized collections can be used to reassemble hundreds of thousands of these populations, the sequencing of which would enable researchers to estimate a variety of genetic indicators across tens of thousands of species and covering 86 per cent of botanical regions on Earth.
"Incredibly, our paper shows that this is widely possible," Eckert said, noting that the specimens "can be used to quantify genetic metrics across tens of thousands of species."
The study also highlights the potential gains from digitizing additional specimens. The authors estimate that completing the digitization of global herbarium collections could allow researchers to quantify genetic diversity for more than half of all known plant species.
For the researchers, the findings underscore the broader value of herbaria. In Canada alone, more than 80 institutions house nearly 10 million plant specimens and serve as educational, cultural and scientific resources. Many now face funding cuts, staffing shortages and closure.
"For many, herbaria serve as critical bridges, connecting science, policy and the public," Eckert said. He added that the collections are "essentially a time capsule, allowing us to go back tens or hundreds of years into the past to better understand how things have changed and how we can protect species, communities and ecosystems into the future."
The authors said they hope their work will encourage new investment, partnerships and research that secure the future of these collections and unlock their full potential for biodiversity conservation.
About the study
The utility of herbarium collections for genetic monitoring by Isaac Eckert, Lucas Eckert, Olivia Rahn, Cameron So, Simon Joly and Laura J. Pollock was published in BioScience.
This study was made possible thanks to funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) as well as the Fonds de recherche du Québec - Nature et technologies (FRQNT).
