Elevated nitrogen allows the weak invasive plant Galinsoga quadriradiata to become more vigorous with respect to inter-specific competition

• Published in: Scientific reports 2018-02, Vol.8 (1), p.3136-8, Article 3136
• Main Authors: Liu, Gang, Yang, Ying-Bo, Zhu, Zhi-Hong
• Format: Article
• Language: English
• Subjects: 631/158/2178; 704/158/2165; 704/158/2178; Galinsoga quadriradiata; Humanities and Social Sciences; Introduced plants; Introduced species; Invasive plants; Invasive species; Mixed culture; Monoculture; multidisciplinary; Nitrogen; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-21546-z

Elevated nitrogen associated with global change is believed to promote the invasion of many vigorous exotic plants. However, it is unclear how a weak exotic plant will respond to elevated nitrogen in the future. In this study, the competitive outcome of a weak invasive plant ( Galinsoga quadriradiata ) and two non-invasive plants was detected. The plants were subjected to 3 types of culture (mixed, monoculture or one-plant), 2 levels of nitrogen (ambient or elevated at a rate of 2 g m −2 yr −1 ) and 2 levels of light (65% shade or full sunlight). The results showed that elevated nitrogen significantly promoted the growth of both the weak invader and the non-invasive plants in one-plant pots; however, growth promotion was not observed for the non-invasive species in the mixed culture pots. The presence of G. quadriradiata significantly inhibited the growth of the non-invasive plants, and a decreased negative species interaction was detected as a result of elevated nitrogen. Our results suggest that competitive interactions between G. quadriradiata and the non-invasive plants were altered by elevated nitrogen. It provides exceptional evidence that an initially weak invasive plant can become an aggressive invader through elevated nitrogen deposition.