The shape is more important than we ever thought: plant to plant interactions in a high mountain community

1. Plant to plant interactions are probably the most important driver of species coexistence at fine spatial scales, but their detection represents a challenge in Ecology. Spatial point pattern analysis (SPPA) is likely the approach most used to identify them however, it suffers from some limitations related to the over-simplification of individuals to points. 2. Here, we propose a new approach called Overlapping Area Analysis (OAA) to test whether the consideration of the shape and orientation of the individuals reveal signs of interactions between species that would remain undetected with SPPA. We used this approach to analyze a fully-mapped cryophilic grassland in Sierra de Guadarrama National Park (Spain), where the crown of each individual plant (i.e. the canopy) was approximated by a polygon. We then computed and compared the total overlapping area between the canopy of a focal species and that of any other species in the community with the expectations of a null model of random...