Climate change helps invasive plants become more destructive

February 5th, 2010 - 2:41 pm ICT by IANS  

Washington, Feb 5 (IANS) Invasive plants could become even more prevalent and destructive as climate change continues, according to new analysis of data stretching back to more than 150 years.
Harvard University scientists, who conducted the study, say that non-native plants, and especially invasive species, appear to thrive during times of climate change because they are better able to adjust the timing of annual activities like flowering and fruiting.

“These results demonstrate for the first time that climate change likely plays a direct role in promoting non-native species success,” says study author Charles C. Davis, assistant professor in organismic and evolutionary biology at Harvard.

“Secondly, they highlight the importance of flowering time as a trait that may facilitate the success of non-native species. This kind of information could be very useful for predicting the success of future invaders.”

Davis and his colleagues analysed a dataset that began with Henry David Thoreau’s cataloguing of plants around Walden Pond in the 1850s, when the famed naturalist kept meticulous notes documenting natural history, plant species occurrences and flowering times.

Since then, the mean annual temperature around Concord, Massachusetts, has increased by 2.4 degrees Celsius causing some plants to shift their flowering time by as much as three weeks in response to ever-earlier spring thaws.

Davis and colleagues compared a plethora of plant traits — everything from height at maturity to flower diameter to seed weight — against species’ response to more than a century and a half of climate change.

Alone among all these traits, plants that have fared well share a common phenology, a suite of traits related to the timing of seasonal events such as flowering, leaf growth, germination and migration.

Conversely, many plants with a less flexible flowering schedule — and thus prone to flowering at suboptimal times — have declined in population, in many cases to the point of local extinction.

The current work builds upon a 2008 paper by Davis and colleagues which showed that some of the plant families hit hardest by climate change at Walden Pond include beloved species like lilies, orchids, violets, roses and dogwoods, says a Harvard release.

“In the United States alone the estimated annual cost of invasive species exceeds $120 billion,” says Davis.

These findings were published in PLoS ONE.

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