Structural importance and conservation value of associated tree species in cocoa agroforestry systems of Côte d’Ivoire

Abstract

Cocoa agroforestry systems can contribute to maintaining woody plant diversity in human-modified tropical landscapes, but the structural importance of associated tree species does not necessarily reflect their conservation value. We assessed both dimensions for associated tree and palm species in cocoa agroforestry systems using 380 plots distributed among ten cocoa-producing departments of Côte d’Ivoire. A total of 3,885 individuals representing 236 associated species were recorded. Structural importance was quantified using the Importance Value Index (IVI), while conservation value was assessed using a Conservation Value Index (CVI) integrating global extinction risk, biogeographical distribution, ecological affinity, and local occupancy rarity. The CVI was calculated for all species and tested under alternative methodological assumptions. The flora included 24 globally threatened species, and 71.2% of species were primarily associated with secondary or mature forests. Structural importance was concentrated in relatively few species, with 17 species accounting for more than half of total community IVI. IVI and CVI were moderately and negatively associated (Spearman’s ρ = −0.344, 95% bootstrap CI: −0.460 to −0.222, p < 0.001), indicating that structurally dominant species did not generally correspond to those with the highest conservation values. Sensitivity analyses showed high overall rank stability across alternative CVI specifications ( ρ = 0.868–0.994), although some variation occurred among highest-priority species. These findings show that structural importance and conservation value capture complementary dimensions of associated woody flora and can jointly inform biodiversity-oriented species prioritization in cocoa agroforestry systems.