China-US grain trade shapes the spatial genetic pattern of common ragweed in East China cities

Abstract

Common ragweed is an invasive alien species causing severe allergies in urban residents. Understanding its urban invasion pathways is crucial for effective control. However, knowledge is limited, with most studies focusing on agricultural and natural areas, and occurrence record-based studies exhibiting uncertainties. We address this gap through a study in East China cities, combining population genetics and occurrence records. Leaf samples from 37 urban common ragweed populations across 15 cities are collected. Genomic and chloroplast DNA extraction facilitate analysis of spatial genetic patterns and gene flows. Additionally, international grain trade data is examined to trace invasion sources. Results indicate spatial genetic patterns impacted by multiple introductions over time. We infer the modern grain trade between the United States and China as the primary invasion pathway. Also, cities act as transportation hubs and ports of grain importation might disperse common ragweed to urban areas. Invasive species control should account for cities as potential landing and spread hubs of common ragweed.

Do Traits Travel? Multiple-Herbicide-Resistant A. tuberculatus, an Alien Weed Species in Israel

“…In contrast, the populations from the Coastal Plain were either ALS-susceptible or ALS-intermediate, indicating that the latter population might be in transition. Furthermore, the Haifa Port (Figure 1), which is close to the Jezreel Valley, and the Ashdod Port, which is close to the Coastal Plain region, both serve for unloading and delivery of imported grains to adjacent feed-production centers, dairy farms, and fishponds, possibly linking the detected A. tuberculatus populations with entry ports, as was reported for common ragweed in China [17]. These findings support our hypothesis that there were several independent introductions of this A. tuberculatus.…”

“…The unique distribution of A. tuberculatus in Israel indicates at least three different invasion events, presumably via imported grain shipments, with further dispersal powered by anthropogenic activities, as recently described for other invasive species in China [11,17]. The first invasion event was recorded in the Hula Nature Reserve, a habitat for water birds in the Hula Valley that currently serves as a crane (Grus grus) feeding site and is heavily infested with A. tuberculatus.…”