In dust-protected cabinets across the world's herbaria, pressed flowers and leaves from centuries past are quietly rewriting the story of how plants have changed. A groundbreaking McGill University study reveals that these fragile specimens—often overlooked relics gathering dust in institutional corners—hold the genetic secrets to understanding which plants are most vulnerable, most resilient, and most at risk of vanishing forever.
Researchers analyzed more than 51 million digitized herbarium records and found they could reconstruct over 16,000 plant populations spanning 41 thousand species and reaching back more than 250 years into history. That's a window into genetic change unprecedented in its scale and depth. For scientists studying conservation, this matters profoundly: when plants lose genetic diversity, they lose the flexibility to adapt to climate shifts, new pests, and changing conditions. Without knowing how genetic diversity has changed over time, conservation efforts operate partly blind.
"Humanity's vast trove of historical plant specimens offers an unparalleled view of population-level genetic change through time," said Isaac Eckert, a Ph.D. candidate at McGill's Department of Biology and lead author of the study, published in the journal BioScience. Currently, population-level genetic data for most plants—the kind of information that lets scientists track whether a species is gaining or losing the variation it needs to survive—remain scarce, especially over long time scales. Herbaria fill that gap.
The research team developed a method to organize specimens into historical populations using location data, collection dates, and what biologists know about each species' natural history. The results are striking: existing digitized collections could reassemble hundreds of thousands of these populations. If researchers sequenced the genetic material in those specimens, they could estimate crucial genetic indicators across tens of thousands of species, covering 86% of botanical regions on Earth. The potential extends further still. The authors estimate that completing digitization of global herbarium collections could enable genetic diversity measurement for more than half of all known plant species—a transformation in our capacity to monitor the living world.
Yet these collections face a quiet crisis. In Canada alone, more than 80 institutions house nearly 10 million specimens but many now face funding cuts, staffing shortages, and possible closure. Eckert frames the deeper stakes: "For many, herbaria serve as critical bridges, connecting science, policy and the public. 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."
This research carries a hopeful message wrapped in urgency. The specimens are already there, already preserved, already waiting. No new expeditions are required—just the sequencing and analysis of what humanity has already collected. By investing in digitization, sequencing, and the herbaria that steward these collections, researchers can unlock a genetic archive that reshapes our understanding of plant vulnerability and resilience. The study's authors hope their findings will spur investment and partnerships to secure these collections and unlock their full potential for biodiversity conservation in an age when plants need every advantage they can get.