Potential effects of domestication on non-native plant invasion risk.
Plant domestication can increase propagule pressure and alter functional traits that may contribute to invasion risk, such as high productivity. Domesticated biotypes (i.e., any cultivar, variety, or other infraspecific taxa that have been domesticated) have a unique evolutionary history that often involves enhanced propagule pressure, selection of traits for human use, and cultural practices to increase establishment success. These elements can alter the invasion process from that of non-domesticated non-native species. Understanding which traits are consistently selected for, how strongly those traits are altered by selection, and in which cases they influence invasion risk would facilitate actions that reduce impacts of domesticated biotypes on natural and agricultural systems. We identified commonalities in trait selection and management intensity among groups of domesticated biotypes selected for particular purposes (e.g., food, ornamental, and biomass production) that indicate predictable invasion risk and management approaches for biotypes from each group. Broadly, food crops that rely on high intensity management tend to have relatively low invasion risk, while biotypes developed for ornamental purposes are subject to more variable management intensity and may have greater risk of establishment and spread in natural areas without cultural practices (e.g., weeding, fertilizer). Biomass-producing biotypes are usually bred for high productivity under low management intensity and have a high-risk of becoming invasive. For groups of domesticated plants bred for different purposes, and across all management levels, efforts to reduce risk of producing invasive biotypes include selection of parent taxa with low invasion risk, development of domesticated biotypes focused on specific low-risk traits and dependence on cultural practices, and selection of durable low-risk traits over consecutive generations.