Community-scale effects and strain: Facilitation beyond conspicuous patterns

The large majority of 'facilitation studies' focus on benefactor-beneficiary interactions. However, this may skew our view of the role of facilitation toward systems where it is most conspicuous, and perhaps toward harsh environments where discrete vegetation cover and pattern suggestive of facilitation are more common. Here we argue that a particular benefactor species is not required for facilitation to occur. Where vegetation cover is continuous, the community as a whole can ameliorate the abiotic conditions (community-scale facilitative effect) and any species from the assembly experiencing stress (strain) could be facilitated. As a consequence, community-scale facilitative effect might be generally common but often inconspicuous. Whether this community-scale facilitative effect is influenced by particular characteristics of the vegetation cover is still largely unknown (e.g. biomass, species richness, functional composition and diversity). Expanding our research on facilitation beyond benefactor-beneficiary interactions and considering together the concept of community-scale effect and strain might be key to progress our understanding of the general role of facilitation for species coexistence, ecosystem function, species distribution or climate change impact.

Automated summary

Facilitation studies do not necessarily require specific benefactor species to occur; when vegetation cover is continuous, the entire community can ameliorate abiotic conditions and facilitate any species experiencing stress. The community-scale facilitative effect may be generally common but often inconspicuous.