Invasion ecology of black henbane (Hyoscyamus niger L.) in sagebrush, northern mixed grass, and shortgrass steppe ecosystems

Invasive plants are rapidly becoming a major concern in rangeland ecosystem management and restoration. Understanding and considering the ecology of the invaded community and the invader can be an important component of invasive plant management; however, research is needed to fully implement an ecological approach. Black henbane range expansion appears to be increasing with escalating disturbance in the Intermountain West; however, conditions necessary for black henbane establishment and performance in rangeland ecosystems are largely unknown. We designed a set of field and greenhouse experiments to better understand black henbane biology and invasion ecology in shortgrass steppe, northern mixed grass prairie and sagebrush ecosystems. We conclude that black henbane is an opportunistic species requiring an open niche and soil resources such as moisture and available nitrogen for establishment. It does not compete well with mature, established grass species commonly utilized in restoration and was unable to invade intact native plant communities in the three studied rangeland ecosystems. If black henbane develops a rosette and overwinters, seed set is highly likely the following year. Black henbane is a prolific seed producer capable of producing thousands of seed per plant and seeds are highly viable. An ecological approach for invasive plant management regarding black henbane would include: (1) control of existing plants prior to seed set, (2) seeding of competitive grasses to sequester soil resources in areas prone to invasion, and (3) maintaining healthy plant communities in these rangeland ecosystems.