PLoS ONE 5, e8878 (2010)

Climate warming could exacerbate species invasions and their often-negative ecological impacts if non-native plants continue to respond better to changing conditions, a study warns.

Using a 150-year record of seasonal plant data started by US poet and naturalist Henry David Thoreau, Charles Davis at Harvard University in Cambridge, Massachusetts, and his colleagues analysed the long-term changes in the flowering times of native and non-native plants in Concord, Massachusetts, near where Thoreau lived.

The average yearly temperature in Concord has increased by 2.4 °C since the 1850s. Invasive species have adapted more quickly to these changes in temperature, shifting their flowering time an average of 11 days earlier than native plants over the past 100 years. For example, the non-native mayweed chamomile now flowers 23 days earlier, whereas some natives are still flowering at the same time of year as in 1900, potentially putting them out of sync with their pollinators.