Aim: Plant invasions pose a serious risk to biodiversity, and living collections in botanic gardens are recognized as a potentially important source of alien plant introductions. However, it is not yet known how the risks from botanic gardens compare with other socio-economic and environmental factors in influencing the regional distribution of alien plant introductions.

Location: China

Time period: 1840 – 2018

Major taxa studied: All vascular plants

Methods: We compiled a dataset of the locations of first records and introduction pathways for 454 plant species naturalized in China and used boosted regression trees to evaluate the roles of the number, size, and age of botanic gardens, local climate, native species richness and trade on the total number of first records of alien plants at both the city and province level.

Results: The botanic gardens with large living collections played the most important role in influencing the total number of first records of alien plant species at both the city and province scale. However, the importance of botanic gardens depended on the introduction pathway of naturalized species. The first records of alien species introduced for horticulture were more influenced by the attributes of botanic gardens. On the other hand, the first records of alien species introduced for agriculture were associated with climate variables, and first records of alien species introduced accidentally were strongly shaped by trade.

Main conclusions: Our results highlight the importance of botanic gardens in facilitating alien plant introductions across a continent. Given the rapid rise in the number of botanic gardens in Asia since 1950, our results point to these as potential hotspots for future plant invasions. In China, monitoring should be implemented to target botanic gardens, particularly those with large living collections. Extending this approach to other regions would be a sensible first step in monitoring invasions.

The cities and provinces with no first records were not shown in the dataset. We only included provinces and cities in the  mainland of China.