Study Led by N.C. Botanist Shows Plant Extinction is More Common Than Previously Realized

Franklinia
Raleigh

A new study reveals that 65 plant species have gone extinct in the continental United States and Canada since European settlement, more extinctions than any previous scientific study has ever documented. 

Led by Wesley Knapp of the North Carolina Natural Heritage Program, a group of 16 experts from across the United States collaborated to document the extinct plants of the continental United States and Canada for the first time in history. Their groundbreaking report has been published by the international journal “Conservation Biology” (https://conbio.onlinelibrary.wiley.com/doi/abs/10.1111/cobi.13621).  

The team found that most plant extinctions occurred in the western United States, where the vegetation was minimally explored before widespread European settlement. Because many extinctions likely occurred before scientists explored an area, it is extremely likely the 65 documented extinctions vastly underestimate the actual number of plant species that have been lost. Previous studies documented far fewer plant extinctions on the North American continent.

“Preventing extinction is the lowest bar for conservation success we can set, yet we are not always successful,” Knapp said. “This study started as an academic question but later developed into an opportunity to learn from what we have lost. By studying the trends and patterns of plants that have already gone extinct, hopefully we can learn how to prevent plant extinction going forward.” 

Of the 65 documented extinctions in the report, 64% were known only from a single location. While conservation often focuses on protecting entire landscapes, this finding points to the importance of small-scale site protection in order to prevent extinctions. 

This work also highlights the need for collaborative science in addressing large-scale conservation issues. The team of 16 botanists from across the United States includes experts with state and federal government agencies, numerous botanical gardens, not-for-profit organizations, regional conservation groups, and academic institutions. To answer the overarching question of what exists and where, the team of experts cross-checked thousands of records to ensure accuracy, discovering that botanical gardens occasionally harbored the last of an extremely rare species and may not have been aware they were doing so.   

Because plants serve as the foundation for most terrestrial ecosystems, the urgency for documenting plant extinctions is especially great if extinction rates rise as predicted over the next century. Anne Frances, lead botanist at NatureServe, states, “In most cases, we can stop plants from going extinct, we just need the resources and commitment to do so.”

Photo cutline: Franklin Tree, (Franklinia alatamaha), NatureServe Global Conservation Status: Possibly Extinct (GX) in the Wild. Photo Courtesy of the John Bartram Association/Bartram's Garden—a cultivated example of this species as no known wild individuals exist.

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