Flower Power

Thoreau’s records help reveal plants’ responses to climate change

St. John's wortObservations taken more than 150 years ago by famed naturalist Henry David Thoreau have helped scientists figure out why non-native plants may thrive under global warming.

Thoreau, one of America’s best-known nature lovers and the author of Walden, monitored the flowering of hundreds of plant species in Concord, Massachusetts during the 1850s. His work was continued by an amateur botanist, a landscape designer, and most recently, researchers at Boston University. Now, a team has used this long-running dataset to see whether Concord’s native and non-native plants have dealt differently with climate change.

Non-native species were more successful than native species at altering their flowering times in response to temperature shifts, the researchers found. Between 1900 and 2006, invasive plants changed their growth schedules to flower an average of 11 days before native plants. Species that carried out these adjustments have also greatly increased in abundance, says co-author Charles Davis of Harvard University.

Climate change might encourage more non-native plants to take root in the future, according to the PLoS ONE study. But watching for changes in flowering times could help scientists predict which species are most likely to become invasive. – Roberta Kwok

Source: Willis, C., Ruhfel, B., Primack, R., Miller-Rushing, A., Losos, J., & Davis, C. (2010). Favorable Climate Change Response Explains Non-Native Species’ Success in Thoreau’s Woods PLoS ONE, 5 (1) DOI: 10.1371/journal.pone.0008878

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