Thoreau demonstrates invasive plants ahead of their time when it comes to responding to climate change
Willis CG, Ruhfel BR, Primack RB, Miller-Rushing AJ, Losos JB, Davis CC (2010). Favorable Climate Change Response Explains Non-Native Species' Success in Thoreau's Woods. PLoS ONE 5(1): e8878. PDF.
Summary
Based on a unique historical dataset from Concord, Massachusetts, this is one of the first papers to demonstrate the role of climate change in shaping patterns of non-native plant species’ naturalization and potential invasion. In the more than 150 years since the original dataset was collected, the mean annual temperature of Concord, MA has increased by 2.4°C. The dataset on 587 different species allowed researchers to look at the response of first flowering date to warming temperatures. Shifting flowering time can have ecological consequences for species interactions including pollination. Willis et al. investigated the role of climate in two ways. First, they used the historical data (1888-1902) to see how well a species' first flowering day tracked with the annual spring temperature. Second, they looked at the change in the average first flowering day for species over two time periods (1851-2006 and 1900-2006). Willis et al. distinguished between invasive species and non-invasive, but non-native species (aka naturalized) in their dataset to investigate what makes a species invasive. Results indicated that non-native species differ dramatically from natives in their ability to respond to climate change. Specifically, invasives track seasonal temperature variation better than natives. Invasives have also significantly shifted their flowering time over the last 100 years to be 11 days earlier than natives and 9 days earlier than non-native non-invasives. In line with these phenological results, non-native and invasive species in particular have significantly increased in abundance since 1900 relative to the native flora. Aside from some invasives having bigger flowers (a potential horticultural trade remnant), there was no significant difference in the other measured traits, providing a strong link between climate change, shifting phenology, and ultimate invasion success. Thanks to historic datasets like this one, we can learn a lot about how northeast species are responding to climate change.
Take home points
Non-native species, and invasive species in particular, have been far better able to respond to recent climate change by shifting their flowering time.
The ability to alter growing seasons in response to climate change (‘phenological plasticity’) may be an important predictor of future invasive plants.
As climate change accelerates, non-native species’ ability to respond favorably will likely exacerbate the ecological and economic problems that result from their success. This is still true 13 years after publication.
Management implications
Additional phenological data is essential for assessing and managing future impacts of invasive species in the face of climate change. Collecting these data are important additions to understanding species’ invasions. Check the National Phenology Network for protocols and community science applications
Information on flowering time tracking may allow us to determine if a non-native species is more likely to become naturalized in its introduced range.
Keywords
Phenology; Shifting Seasons; Invasive Plant