Xincong Chen, Wenwen Liu, Yuan-Ye Zhang, Yihui Zhang

This is a plain language summary of a Functional Ecology research article which can be found here.

Human activities can sometimes cause species to be moved beyond their natural ranges to other parts of the world. Some invasive species may have negative impacts on the economy and environment of their new home. Exotic species that are introduced to new places often lack natural enemies, allowing them to have more resources for growth and production of offspring—a phenomenon known as the “big houses, big cars” effect.

Cordgrass (Spartina alterniflora) is a plant native to the United States that has been introduced to several other countries, including but not limited to France, Brazil, South Africa, New Zealand, and China. Cordgrass was introduced to China about four decades ago and has now spread along much of the country’s coast, making China home to the world’s largest cordgrass invasion. To determine if cordgrass showed the “big houses, big cars” effect in China, we cultivated seven and nine populations of cordgrass from both its native and invasive ranges at the southernmost and northernmost sites of their invasive range. We recorded the flowering time, growth conditions, and offspring of each population and compared the trait covariances between cordgrass from the United States and China.

Our results showed that cordgrass from the United States had earlier flowering times and larger plant sizes, while cordgrass from China had earlier flowering times and more offspring. This suggests that cordgrass changes its trait covariances when it is introduced to new areas. Despite facing different environments in these two locations, both populations of cordgrass showed some degree of the “big houses, big cars” effect.