Tree diversity and composition in Mexican traditional smallholder cocoa agroforestry systems

Abstract

The cultivation of cocoa is a commodity of great importance worldwide. In Mexico, cocoa is grown in Tabasco and Chiapas states in agroforestry systems since pre-Hispanic times, where cocoa is grown under the canopy of shade trees. Crops such as sugarcane and extensive livestock production have gradually reduced the area devoted to cocoa cultivation in the region. Yet, farmers keep small portions of the cocoa agroforestry systems to maintain the local floristic diversity. This practice seems to be a successful contribution to plant conservation. To determine the management practices used by farmers in the agroforestry cocoa systems and the diversity of products they harvest, a non-probabilistic sampling was carried out in 38 shade cocoa plots of 20 × 50 m each (19 in Tabasco and 19 in Chiapas). We counted and identified all trees with DBH ≥ 5 cm, recording their height. We estimated canopy cover at 20 points within each plot. Our results show no tree species richness differences between states, but there were differences at the municipality level; Pichucalco (Chiapas) had the highest tree species richness. Considering all tree species, there was a higher tree density in Tabasco than in Chiapas. Regarding only cocoa trees, there was also a higher abundance in Tabasco than in Chiapas. In both cases, farmers obtain a wide variety of products for self-consumption and local market sale from their cocoa agroforestry systems (e.g., timber, fruit, and grains). The wide floristic diversity in these agroecosystems aids native plant species conservation and could favor the increase of agroforestry plantations associated with cocoa cultivation.