Comprehensive review about alien plants in Korea

Species invasions have rapidly increased due to the substantial growth of global trade in the recent past. As the awareness of the negative effects on natural ecosystems derived from alien species has grown, many countries and lawmakers have enacted rules and policies on the conservation of indigenous plants. Unfortunately, in Korea, research on species invasion is seriously lacking despite the growing number of alien species. In the current study, we report alien plants that have intentionally and/or unintentionally been introduced in Korea and also presented a checklist of invasive plants found both in the literature and in field surveys. We reviewed all documented records of alien plants, i.e., scientific papers, illustrated books, and annual reports. We also categorized alien plants by origin, time of introduction, naturalization, and the rate of their spread. The results revealed that there are 619 alien plant taxa (96 families, 353 genera, 595 species, 6 subspecies, 11 varieties, 1 forma, and 6 hybrids) occurring in Korea. Among these, 30 taxa are archaeophytes (Arc.), 214 are potentially invasive plants (PIPs), and 375 are invasive alien plants (IAPs). In addition, IAP taxa consist of grades 5 (widespread, WS) to 1 (potential spread, PS) of alien plants according to the rate of spread in Korea. Our results suggested that the number of alien plants is likely to keep growing; thus, the distribution should be regularly monitored and the list of alien plants must be updated.