Consequences of shade management on the taxonomic patterns and functional diversity of termites (Blattodea: Termitidae) in cocoa agroforestry systems.

Ambele C Felicitas,Marie J Meupia,Bisseleua D B Hervé,Sunday Ekesi,Olubukola O Babalola,Christian T C L Djuideu,Komivi S Akutse

doi:10.1002/ece3.4607

Abstract

Termites have gained importance as major pests in cocoa agroforests. Proper identification of termite species and knowledge on their functional diversity are the first steps in developing environmentally compatible management strategies. We tested the hypothesis that patterns of termite species richness in different cocoa agroforests is related to responses by termite functional groups to changes in shade management. We compared termite assemblages under five cocoa agroforestry systems in Cameroon to assess the impact of shade on termite taxonomic and functional group diversity. Sampling was done using a modified standardized transect method. Two 30 × 30 m quadrates each divided into three transects were laid in four farms at each site. Termites sampled were identified and grouped according to habitats, functional groups, and feeding habits. Sixty‐nine termite species in 33 genera and five subfamilies under two families were sampled. Termitidae was the most dominant family and Rhinotermitidae the least dominant with few species. Termite species richness decreased significantly from the heavy shaded cocoa agroforests (44 species) to the full sun (11 species). Functional group pattern differed significantly in all the cocoa agroforests and within each agroforestry system and dominated by wood and litter feeder species. Many species belonging to this group were responsible to most damages on cocoa trees. Both the richness of termite pests and marketable yield followed a quadratic curve and were found to be lowest and highest in plots with shade cover above 40%. The simulated optimal shade levels for low termite infestations and marketable yield overlapped between 45% and 65% indicating that cocoa agroforestry systems with around 55% shade cover may be optimal to balance termite infestations and marketable yield. Shade maintenance in cocoa agroforests is valuable in reducing termite pest species and conserving soil feeding termites which provide beneficial ecosystem services.

Highlights

Cocoa (Theobroma cacao L.) is shade‐tolerant and traditionally grown under shade trees in complex agroforestry systems, thereby provid‐ ing a refuge for biodiversity and sustaining other ecosystem services (Bisseleua, Missoup, & Vidal, 2009; Rice & Greenberg, 2000)
We showed that shade management in cocoa agroforestry systems strongly impact termite species richness and composition because even though most of the AF systems were spatially autocorrelated, TA B L E 1 List of the 69 termite species collected from the five cocoa agroforestry systems in Cameroon and classified according to their functional, nesting, and feeding groups
The results of our study conclusively showed that richness and evenness of termite species are driven by cocoa shade systems, with emphasis that (a) the number of termite species in the shaded systems was more diversified than that of the unshaded systems, demonstrating that shade management characteristics dictates termite faunal differences; (b) the shaded systems maintained all the termite species found in the full sun systems and harbored a diversity of non‐pest species, suggesting that the establishment of shade in cocoa agroforestry systems conserves important part of functional biodiversity of termites

Summary

Introduction

Cocoa (Theobroma cacao L.) is shade‐tolerant and traditionally grown under shade trees in complex agroforestry systems, thereby provid‐ ing a refuge for biodiversity and sustaining other ecosystem services (Bisseleua, Missoup, & Vidal, 2009; Rice & Greenberg, 2000). In spite of its ecological benefits, recent decades have seen a transformation of cocoa farming in southern Cameroon to more intensified systems by eliminating shade trees to increase short‐term income. This has resulted in a broad range of cocoa plantation management, ranging from low‐input shaded plantations to high‐input full sun plantations (Bisseleua, Fotio, Yede, & Vidal, 2013). In an agroforestry trial in southern Cameroon, Dibog, Eggleton, Norgrove, Bignell, and Hauser (1999) demonstrated that tree canopy cover was positively correlated with termite abundance This implies that agroforestry systems with more shade trees are habitat for more species, many of which help to increase the yield of cocoa, such as termites, ants, and other pollinators

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