Arthur and Mitchel (1989) described three types of populational interactions including neutralism in which neither species is affected by presence of the other,
amensalism in which individuals of one species adversely affect those of the other but are unaffected themselves, and competition in which both species are affected negatively.
Based on Odum (1985), we have implemented interaction models of neutralism (0, 0),
amensalism (0, -), comensalism (0, +), predation (+, -), symbiosis (+, +), and competition (-, -) (Salles et al.