Interactions between facilitator species and Lophophora williamsii (Lem. ex Salm-Dyck) J.M.Coult. (Cactaceae) in a rosetophyllus desert scrub in México

Abstract

Lophophora williamsii (peyote) is a spineless cactus that stands out for its psychoactive alkaloid content and considered vulnerable due to the destruction of its habitat and illegal extraction. The objective of this study is to describe the spatial distribution and interactions between facilitator species and L. williamsii that are important for this species conservation and reintroduction programs. The spatial distribution pattern was determined by Ripley's K-function. To know whether L. williamsii requires facilitator species, 10 plots of 100 m2 each were considered to perform dasometric measurements of the perennial species. Frequency of peyotes under the canopy of perennial species and open spaces was determined. The cardinal directions in which peyote individuals were found under the facilitator species were recorded, as well as soil surface temperature and solar radiation at soil level under the foliage and open spaces. L. williamsii showed an aggregated spatial distribution; 97.7% of peyotes were found under the foliage of facilitator species, where temperature and solar radiation were significantly lower than in the open spaces. Among the facilitator species, those that stand out are Flourensia cernua, Agave lechuguilla, Larrea tridentata, and Prosopis glandulosa. Significantly greater frequencies of peyotes were observed positioned on the northern quadrant of the facilitator crown. The results obtained show that L. williamsii needs the protection of perennial species for its establishment. Thus, the disappearance of these species could put at risk the persistence of peyote in these communities. These findings point out that the conservation and restoration of wild peyote populations require maintenance from the facilitator species.