Fig 3. EICAT+ and EICAT mechanisms and submechanisms.

List of EICAT+ mechanisms and submechanisms (A) and EICAT mechanisms (B). EICAT+ and EICAT mechanisms and submechanisms are also compared to each other (C) based on the outcome of the interaction for native and alien taxa. Colors of rows and connecting lines reflect different rationales behind the formulation of the EICAT+ mechanisms and submechanisms, with the different colors and symbols that indicate [yellow and asterisks “*”] mechanisms present in both EICAT+ and EICAT but in which the functional roles of alien and native taxa are reversed (e.g., in EICAT+, the alien taxon is the prey, whereas in EICAT, the alien is the predator); [green and degree signs “°”] mechanisms that are unique to EICAT+ (e.g., dispersal facilitation through pollination); [pink and daggers “†”] mechanisms present in both EICAT+ and EICAT but in which impact direction is reversed because of overcompensation (e.g., in EICAT+, the alien taxon increases growth of the native taxon through browsing-mediated overcompensation, whereas in EICAT, the alien taxon decreases growth of the native taxon through browsing; [blue and tildes “~”] mechanisms present in both EICAT+ and EICAT but in which impact direction is reversed (e.g., in EICAT, the alien taxon decreases a biodiversity attribute by impacting the chemistry of the ecosystem, and in EICAT+, the alien taxon increases a biodiversity attribute by impacting the chemistry of the ecosystem). The symbols +, −, 0 indicate positive, negative, and neutral outcomes of interactions between a native and an alien taxon. In C, arrows indicate impacts of an alien to a native taxon (orange arrow: positive impact; blue arrow: negative impact). Symbols were courtesy of the Integration and Application Network, University of Maryland Center for Environmental Science (ian.umces.edu/media-library).