TORONTO, ON - University of Toronto research has found that purple loosestrife an invasive species that competes with native plants for light and nutrients and can degrade habitats for wildlife has evolved extremely rapidly, flowering about three weeks earlier as it has spread to northern Ontario. This has allowed populations of the species to thrive in the colder climate with a more than 30-fold increase in seed production.
"The ability of invasive species to rapidly adapt to local climate has not generally been considered to be an important factor affecting spread," said Dr. Rob Colautti, who conducted the research as a Ph.D. student in U of T's Department of Ecology & Evolutionary Biology under the supervision of Professor Spencer Barrett.
"Instead, factors such as escape from natural enemies including herbivores, predators, pathogens or parasites were thought to explain how species become invasive. We found that the evolution of local adaptation to climate in purple loosestrife increased reproduction as much as or more than escaping natural enemies. Understanding that species can evolve rapidly to local climates is important for predicting how invasive species spread and how native and non-native species alike will respond to climate change."
To determine whether populations have evolved local adaptation, the scientists collected seeds from three different climatic regions (north, south and intermediate latitudes in eastern N. America) and then grew them at three sites spanning the distribution of the species to see if there were differences in survival and reproduction, i.e. fitness. They found that 'home' plants collected from latitudes most similar to each common garden location always had higher fitness than the 'away' plants. For example, plants collected from northern latitudes had the highest fitness when grown at the northern site in Timmins, Ontario but the lowest fitness when grown at a southern site in northern
|Contact: Kim Luke|
University of Toronto