A research group led by Noriko Maruyama (then a graduate student at the University of Tokyo Graduate School), in collaboration with the Society for the Continuation of the University of Tokyo Farm and Experimental Forest, and the Chiba University Graduate School, was able to determine the flowering schedules of hundreds of weeds that grow around us. They discovered that the weed's ``region of origin'' has a major influence.
An alien community in a region is a collection of organisms that have originally adapted to the environment of their native region.However, with regard to alien species, it is believed that those species that adapt to the environment during the invasion process survive, and there has been little verification of the idea of linking traits to the region of origin.
The research group has developed an illustrated database covering 537 species of foreign weeds in Japan, conducted a total of 1 field surveys (9 records) at 234 locations per year, and has been working with citizen volunteers (Association for the Continuation of the University of Tokyo Farm/Exercise Forest) for 3,112 years. Flowering time data was collected and analyzed using three methods: monthly plant surveys (25 records).
As a result, most of the exotic weeds that grow in Japan are native to Europe when they bloom in the spring (March to May), and are native to North America when they bloom in the fall (September to November).This trend showed that even within the same family, the flowering time was clearly different depending on the region of origin.For example, even within the Asteraceae family, spring-blooming dandelions and pigweeds are native to Europe, while fall-blooming ragweed and coreweed are native to North America.
Furthermore, when researching literature on the flowering times of native weeds in agricultural land and urban areas in Europe and North America, we found that in Europe, many native weeds bloom in the spring, and in North America, many native weeds bloom in the fall.In other words, the weed's flowering time is different in Europe and North America, and even after it invaded Japan, it can be said that it maintained its flowering characteristics depending on its region of origin.
The research group says the results demonstrate the importance of information on the area of origin of alien species when it comes to invasiveness and management.
Paper information:【Biological Invasions】Effects of biogeographical origin on the flowering phenology of exotic plant communities
