Despite the urgent nature of solving the “woody invaders problem”, its definition and management remain controversial. In Portugal, there is still a worrying growth in the area occupied by these species.
Biological invasions are a major threat to biodiversity conservation objectives. The awareness of the impacts of exotic species on natural and semi-natural ecosystems motivated the debate around their definitions and methods of controlling and managing their densities.
In the bibliography on biological invasions, concepts such as weed, invasive, adventitious arise, whose definition is sometimes ambiguous and subjective. In general, these terms refer to undesirable and harmful plants, as they grow aggressively, dispersing easily and displacing other plants in the ecosystem.
The various definitions fall within the context of the damage associated with the presence of exotic species or take into account the invasion process itself. In this way, the nature of the damage conditions two different perspectives: the herbological (or anthropic) perspective, which highlights the impacts of these on human activities, which includes the term weed; and the ecological (or conservationist) perspective, established based on the preservation of communities and inhabitants, which includes the term adventitia.