Species interaction: Revisiting its terminology and concept

Terminology can profoundly influence scientific research. Here, I discuss the term “species interaction,” which constitutes the core of ecology. The term has the merits of underlying many fundamental ecological ideas (e.g., competitive exclusion, trophic cascade and keystone predation) and making ecological research more interdisciplinary (e.g., biodiversity conservation and ecosystem management). Meanwhile, it has the demerits of causing problems of synonymy and polysemy, masking the fact that interactions occur at the individual level, and reinforcing the counterfactual view that an ecological community is a network of interactions between homogeneous species. This means that the facile use of the term may impede our understanding of community dynamics, which is a great concern considering recent evidence that individual heterogeneity is ubiquitous (e.g., due to ontogeny, sex and genotype) and crucial for community dynamics. To further extend the debate, I present some prospective scenarios in which future research trends may affect the importance of the terminological debate. For example, the term may obtain other definitions due to the establishment of new analytical techniques (e.g., DNA metabarcoding and causation analysis), or the debate may become obsolete if a consensus is reached that interactions occur between individuals (i.e., a paradigm shift). These arguments indicate that how we can use the term depends on how we view interactions between organisms. I suggest that multifaceted approaches that consider not only the terminology but also its associated concept and relevant research methodology are needed to overcome the issues of such ambiguous terminology and guide the future development of ecology.