Definition: A possibly ambiguous term used to describe the presence of the taxon in a region. Common definitions include newly arrived; vagrant; in flux. May or may not have been introduced by human activity.
Definition: position of an organism in a food web. May be described verbally with descriptors including primary producer, herbivore or carnivore. If described numerically, 1 indicates a primary producer, 2 a herbivore, and so on up the food web.