How to Invade an Ecological Network

Invasion science is in a state of paradox, having low predictability despite strong, identifiable covariates of invasion performance. We propose shifting the foundation metaphor of biological invasions from a linear filtering scheme to one that invokes complex adaptive networks. We link invasion performance and invasibility directly to the loss of network stability and indirectly to network topology through constraints from the emergence of the stability criterion in complex systems. We propose the wind vane of an invaded network – the major axis of its adjacency matrix – which reveals how species respond dynamically to invasions. We suggest that invasion ecology should steer away from comparative macroecological studies, to rather explore the ecological network centred on the focal species. Invasion performance can be tentatively explained by the traits of alien species relative to those of natives, recipient site characteristics, and introduction pathways. The rush to identify invasive traits from comparative studies has not yet led to predictability at a satisfactory level. Synergies among invasion science, network ecology, and community ecology warrant increasing attention. Winners and losers in recipient ecosystems are the results of the multiplayer game between natives and aliens, as well as human factors. Statistical tools that can handle multispecies interactions are on the horizon.