Sandy Paradise or Rocky Hell? Investigating Soil Influence on Thrinax radiata Palm Groves from a Caribbean Island

Palm groves are abundant in southeastern Mexico and have significant economic and socio-cultural relevance. Studies on the production and management of palm groves are abundant in the area. However, an ecological approach is scarce but necessary for conserving these overexploited species. Palm groves are abundant on the island of Cozumel and develop on contrasting substrates: rocky and sandy ones. Thus, we aimed to explore how soil types affected community structure and composition. We sampled a total of 2900 m² (29 plots of 10 × 10 m) of palm grove, 13 growing in sandy soil and 16 in rocky soil. We registered the species present in each plot, plant density, cover, height, and DBH. A hierarchical cluster analysis re-grouped the sampled plots based on their floristic affinities, and thus, we had 17 plots for the sandy substrate and 12 from the rocky substrate, which were used for later analyses. The dominant species in both palm groves was Thrinax radiata, and species richness was the same in both soil types (33 species). Contrasting substrates resulted in different community composition and structure. The palm groves from the sandy substrate had more vines but fewer shrubs and higher plant density, height, and DBH. The above suggests that the low availability of soil in the rocky substrate does not allow the same state of vegetation development that occurs in the sandy substrate.