Alien plants often successfully invade non-native environments by their
adaptability and pregenetic differentiation. In order to rapidly spread and
expand their living distribution, invasive plants often undergo adaptive
evolution of traits following their introduction. However, few studies have
focused on the changes of genetic structure after the establishment of
invasive populations. Cardamine hirsuta, a widespread invasive plant in
Japan since the 1970s, was used in this study to assess changes in
population structure over time. We conducted two samplings from 31 sites
in eastern Japan in 2014 and 2021, and compared the changes in their
population structure. Our results show that there are four linages and four
populations in 2014, while there are six lineages and seven populations in
2021. In 2021, one population was mainly located in northern of eastern
Japan; two populations were mainly distributed in southern of eastern
Japan; the other three populations were widely distributed. Additionally,
one population was identified as a mixture. Our results suggest that the
population structure of invasive plants changed after the invasion
happened at high speed. Therefore, it is necessary to strengthen the
exploration of population structure to control the spread of invasive plants