Effect of land-use history on tree taxonomic and functional diversity in cocoa agroforestry plantations

The impact of land-use history on shade tree diversity in cocoa agroforestry plantations needs exploration to facilitate effective biodiversity conservation. Thus, we evaluated the effect of land-use history on the taxonomic and functional diversity of the tree shade community in cocoa agroforestry plantations in the Soconusco region of Chiapas, Southeastern Mexico. We selected seven cocoa agroforestry plantations: three with high-intensity management (initially open fields, sown shadow trees, agrochemical use) and four with low-intensity management (under the forest canopy, shadow trees from natural regeneration, no agrochemical use). We measured the diameter at breast height (dbh), height, taxonomic identity, human use, and functional traits (growth rate, successional/ecological status, dispersal syndrome and leaf phenology) of all shade trees with dbh >= 10 cm within five 200 m2 circular plots per plantation. Additionally, we gathered the plantation's land-use history from interviews with local farmers. We calculated taxonomic and functional diversity indices for each management scheme and assessed the impact of land-use history on structure, taxonomic, and functional diversity. We observed lower taxonomic and functional diversity and higher species dominance in high-intensity agroforestry plantations as compared to low-intensity ones. High-intensity plantations consisted of dense tree communities with low taxonomic and functional diversity, dominated by fast-growing, economically valuable species such as cedar (Cedrela odorata). Tree richness and abundance were strongly influenced by land-use history, including canopy openness, pest control, and fertilizer type. Although cocoa agroforestry plantations in open sites maintain a low diversity of shade trees, they contribute to biodiversity recovery. Landowners' decisions to improve land productivity significantly impact the shade tree diversity of cocoa agroforestry plantations. To enhance the conservation value of these plantations and their ecosystem services, including soil enrichment, pollination, and pest control, promoting a high-diversity shade tree layer is crucial, ultimately benefiting agroforestry production.