Mapping species niche and fitness differences for communities with multiple interaction types

Modern coexistence theory (MCT) holds the potential to study the ability of species to avoid extinction (i.e. to persist) across community types but is rarely applied beyond pairs of competing species. Here, we show that this limitation can be overcome by mapping species according to their niche ((Formula presented.)) and fitness differences ((Formula presented.)). This application provides three main benefits to study processes of multispecies persistence across trophic levels. First, (Formula presented.) mapping introduces a novel categorization of species and communities according to the high-level processes at play: frequency dependence (negative or positive), the occurrence of positive species interactions (facilitation and mutualism) and whether persistence is possible without the presence of other species because of trophic interactions, such as herbivory or predation. Therefore, this mapping can be seen as a toolbox to describe how species persistence depends on species interactions. Second, (Formula presented.) mapping facilitates studying how species persistence responds to environmental changes that shift intrinsic growth rates and the strength and sign of species interactions. Third, (Formula presented.) mapping has the potential to foster synthesis across community types because it can accommodate co-occurrence of positive, negative and neutral interactions between species. We, therefore, argue that (Formula presented.) mapping can promote collaboration across sub-fields, as it provides a common concept to link disparate ecological communities.