Facilitation network in phryganic plant communities: evidence from a Mediterranean island

Plant to plant interactions are key drivers of community structure and assembly. We investigate the effect of facilitation on phryganic plant community structure, focusing on plant crown size, and whether the identified facilitative interactions related to community architecture are common in arid environments. We analysed the spatial patterns of 11 species in an arid area in Cyprus. A matrix was created to illustrate the associations between recruited and canopy species, which were found to be more positive than expected by chance, based on the Chi-square test. The corresponding indices of nestedness and connectance were calculated. The associations between recruited and canopy species were found to be positive, exhibiting a high nested structure (p < 0.001) with a 26% connectance in a non-random nested pattern. The presence of facilitative interactions was confirmed by the almost double number of recruits under the canopies of facilitators versus open ground. Ziziphus lotus, demonstrated the highest facilitation capacity (ca. 1.4 times higher than expected; covering ca. 57% of the area occupied by the nurses). Thymbra capitata and Noaea mucronata followed. The high degree of regularity in the assembly of plants within the community suggests that a facilitator’s network is fundamental for maintaining plant diversity in phryganic communities.