The role of horticulture in facilitating plant invasions

Domestic gardens play a dominant role in selecting alien species with adaptive strategies that facilitate naturalization

Ornithogalum umbellatum
Common Star-of-Bethlehem (Ornithogalum umbellatum) observed in Atlanta, USA by mrsdyne. Photo via iNaturalist (CC BY-NC 4.0)

More than 13,000 naturalized alien species of vascular plants have been recorded worldwide, and horticulture is believed to be a main pathway of plant invasions. Botanic gardens play a vital role in conserving plant diversity and preventing extinction but they also cultivate many species with invasion potential.

Examining the role of horticulture in plant invasions, this study rigorously examines the direct and indirect relationships between species traits, horticultural use, native range size and naturalization success. Using a dataset of nearly 4,000 species with defined adaptive strategies, the authors reveal that species grown in botanic or domestic gardens are significantly more likely to become naturalized than those not cultivated.

They also find that naturalization incidence and extent is directly related to adaptive strategy, but more importantly—a cultivation bias as species with the same adaptive strategy is more likely to be cultivated. In other words—horticulture isn't just a major pathway for invasions, it also tends to select alien species with highest invasive potential.

Original article

Guo W, van Kleunen M, Pierce S, Dawson W, Essl F, Kreft H, Maurel N, Pergl J, Seebens H, Weigelt P and Pyšek P (2019) Domestic gardens play a dominant role in selecting alien species with adaptive strategies that facilitate naturalization. Global Ecology and Biogeography. Wiley 28(5): 628–639. Available at: https://doi.org/10.1111/geb.12882.