Biology and anthropology of plant invasions

Abstract

Invasive plants have significant effects on humans and cause economic, environmental, aesthetic and biological harm to biodiversity, ecosystem function, and human welfare. The appearance of invasive plants in terrestrial and aquatic landscapes is associated with perturbations caused by human population growth and activity. Herein is posed a conjecture that a successful plant invasion is the consequence of the presence of a species possessing life history traits suitable to exploit opportunities available at a locality. Given these two conditions, a successful invader must disperse into, colonize and occupy that locality for some period of time. The last requirement is that humans must perceive some invasions as a problem. Without all these events occurring, a plant is not considered invasive. Perception of a plant as invasive is a complex, often subjective process. Inspection of public policy and reflection on human value systems provides a more systematic method of understanding how human activity creates selection pressure and opportunities for invaders. The human role in creating these opportunities includes the impact of human population size and growth, dispersal of invasive species propagules in global trade, direct and indirect disturbance by human activity, human values and culture, and the organization of the scientific academy in researching invasion biology. Utilization and exploitation of the highly adapted traits for invasion may provide a benefit to humans, as well as provide impetus to preserve valuable germplasm resources from changes in agroecosystems with the introduction of new biotechnologies.