Biodiversity is affected by changes in management intensity of cocoa-based agroforests

Abstract

In the humid tropics, the rapid rate of deforestation has resulted in a race to protect remaining forest patches that are increasingly isolated within a rapidly expanding agricultural matrix. In these landscapes, a significant area consists of complex agro-forestry systems with high structural and functional plant diversity, providing critical resources for biodiversity conservation, such as food and habitat. Although not a substitute for natural forests, these anthropogenic habitats are gaining increasing conservation value as deforestation progresses. Shaded tree crops, such as cocoa, provide habitats for numerous forest dependent species of high conservation value and play a largely undocumented role in providing other ecological services. Following previous work on the botanical composition and structural complexity of cocoa agroforests in Talamanca (Costa Rica), we assessed if differences in the vegetation composition and structure of 36 cocoa agroforests could affect the wild diversity of small mammals, amphibians, reptiles, soil and litter macro-invertebrates and epiphytes found on cocoa trees and associated plants. Results show that Alpha-diversity is not affected by changes in vegetation structure and composition, except for amphibians and epiphytes found on cocoa trees. However, five taxa among eight showed distinct species composition patterns when compared among cocoa-based agroforestry clusters and with forest control. We showed that beta-diversity assessment enhances our understanding of the effect of management intensification on species composition and on habitat quality. The proper design of the shade component in these AFS will certainly play a key role in segregating wild species hosted in these systems and will open a new field of research for the intensification of both cocoa and associated productions in these highly diverse systems. (Résumé d'auteur

Trade-offs between crop intensification and ecosystem services: the role of agroforestry in cocoa cultivation

“…There is much scope for promoting tree diversity through use of a range of species according to their suitability to match ecological niches, livelihood requirements of farmers and provide a range of ecosystem services such as crop productivity, production diversification, climate adaptation, pest and disease suppression, pollination, soil fertility, water yield and carbon sequestration; and, thereby, sustain cocoa yield. As reported in this present issue by Smith Dumont et al (2014), Cerda et al (2014) and Deheuvels et al (2014), farmers in West Africa and Latin America overwhelmingly want to have more trees on their farms to sustain their cocoa production, diversify their revenues, improve their livelihood and adapt to climate change. Many farmers are particularly aware of the buffering effects of shade trees against drought and heat stress experienced by cocoa in the dry season.…”

“…The multifunctional role of shade trees for farmers' livelihoods and the conservation of natural resources (particularly biodiversity) has been established, highlighting how shade trees in cocoa agroforestry systems enhance functional biodiversity, carbon sequestration, soil fertility, drought resistance and, weed and biological pest control (Clough et al 2009;Tscharntke et al 2011;Vandermeer 2011;Somarriba et al 2012;Deheuvels et al 2014). This suggests a need for more comprehensive assessment of the long-term effects of shade removal on cocoa yield over a wide range of contexts, in terms of both socio-economic and ecological conditions (Coe et al 2014).…”

“…Three further articles illustrate how risk-averse farmers use shade trees as a long term strategy to avoid vulnerability of their cocoa systems against insect and disease outbreaks and climate change, particularly water and heat stresses (Gyau et al 2014;Jagoret et al 2014;Smith Dumont et al 2014). The relationships between management intensity of cocoa and the conservation of biodiversity are explored by Tadu et al (2014) and Deheuvels et al (2014). The provision of ecosystem services by cocoa agroforestry is documented by Vebrova et al (2014) and the role of organic certification in promoting carbon sequestration and tree diversity in cocoa systems is explored by Jacobi et al (2014).…”

The role of cocoa agroforestry systems in conserving forest tree diversity in the Central region of Cameroon

“…The socio-economic and ecological importance of CAFS is acknowledged worldwide. In Costa Rica, Deheuvels et al (2014) showed that shade tree crops such as cocoa provide habitats for numerous forest dependent species of high conservation value. In Indonesia, Clough et al (2009) revealed that CAFS provide habitats for wildlife, while in Cameroon, they serve as reservoirs for seeds from the forest (Leakey and Tchoundjeu 2001;Sonwa et al 2001) outside protected areas.…”

Increased pollinator habitat enhances cacao fruit set and predator conservation

“…Cacao (Theobroma cacao L., Malvaceae) is a cauliflorous, neotropical, understory tree native to the northern parts of South America (Motamayor et al 2002) that produces cocoa, which is among the world's most economically important fruit tree commodities (Edwin and Masters 2005). The sustained increase in global cocoa consumption (Rice andGreenberg 2000, Lass 2004) has led to a worldwide push for the intensification of cacao cultivation (Bisseleua et al 2009, Deheuvels et al 2014. The transition of cacao cultivation from traditionally diverse agro-ecosystems to modern, simplified, and chemically dependent agricultural models (Moguel andToledo 1999, Vaast and, may inhibit natural biodiversity-driven ecosystem services such as pollination and pest control that often benefit productivity (Schroth and Harvey 2007, Clough et al 2009, Gockowski and Sonwa 2011, Wielgoss et al 2014.…”