Fruit species composition and diversity patterns in eight age classes of cocoa agroforests, Ghana

Abstract

Fruits species incorporation in cocoa farms is characteristic of tropical cocoa agroforestry systems. This study assessed fruit species composition and diversity in eight age classes (C) of cocoa agroforests (CAFs). Fruit species were inventoried on 72 (100 × 100 m) plots among eight CAF age classes—C1 (1–5 years), C2 (6–10), C3 (11–15), C4 (16–20), C5 (21–25), C6 (26–30), C7 (31–35), C8 (36–40 years)—within three communities. Fruit species abundance, richness and diversity were estimated using Broken Stick model, Chao-1 model and Hill numbers respectively. A total of 445 individuals, 11 species and 8 families were recorded over a 72 ha area. Species abundances differed significantly ((F = 9.84, df = 26.5, p = 5.273E-06; Welch’s F test) among the age classes. Majority of species (78.4%) were introduced as new plants into the CAFs and were dominantly P. americana (n = 117), Citrus spp. (n = 82), C. nucifera (n = 74) and Musa spp. (n = 71) while A. occidentale (n = 2) was the least. Diversity was highest for C2 and least for C1. Chao-1 estimate showed that C5 was richest in fruit species, while C8 was the poorest. The presence of rare indigenous species (Synsepalum dulcificum and Chrysophyllum albidum) shows that fruit species management in CAFs alter vegetation composition but still contribute to biodiversity conservation goals in agricultural landscapes. Further research that relates fruit species diversity or abundances to cocoa productivity, soil properties and carbon sequestration is recommended.