Paper: Local farmers shape ecosystem service provisioning in West African cocoa agroforests
1.
In many tropical areas, forests have almost undergone complete decline. In this context, agroforestry has often been acknowledged as fostering compromises between crop production, local income diversification and the preservation of forest ecosystem services.
2.
Cocoa agroforestry capacity to provide ecosystem services has mainly been studied through a management intensification gradient summed up as a shade rate. This paper proposes an alternative reading grid based on different trees origins that agroforests often combine:
(i) Remnants, left-alive during deforestation,
(ii) Recruits that have colonized the agroforest and
(iii) Planted trees.
This grid has been applied to 137 cocoa fields in the south of Ivory Coast to assess the impact of farmers management on provisioning trees ecosystem services (i.e.: carbon storage, diversity, food, medicine, timber and agronomic services to cocoa trees).
Location of the study regions along a climatic, forest vegetation and historical gradient
3.
(i) Little environmental effect was found to explain ecosystem services provisioning.
(ii) However, with regard to their origins, trees provide different services: remnants stock most above-ground carbon, recruits are the most diverse and provide medicinal resources and planted trees bring food resources.
(iii) According to their origin, trees belong to different species or are at different stages of maturity so that trees from different origins play a complementary role in providing ecosystem services.
Our results suggest that Ivorian cocoa agrosystems are so shaped by human management of associated trees that ecosystem services are weakly linked to environmental variables. Two neighboring fields in similar environmental conditions will provide very different services according to farmers’ management.
The importance of tree cohorts to understand service provisioning in cocoa field. The observed values (dots) of a targeted cohort are regressed (dashed lines) against the summed values of the non-targeted cohorts with 95% confidence intervals reported in shaded areas
4.
Synthesis and applications Preserving remnants while clearing forest is irreplaceable for large-scale climate mitigation while providing farmers with trees seedlings may have only little impact on carbon stocks. To strengthen complementarities between human-brought and human-selected trees, private companies providing trees to farmers should supply them with different valued trees from the ones they already plant or easily find in recruits. At landscape scale, policy should encourage remnants preservation to ensure that those remnants can feed the cohort of recruits with propagules thus allowing the survival of the species throughout several cycles of perennial crops
