Agriculture and Environment: Cocoa
Environmental impacts of production: Forest degradation
Much cocoa cultivation in the world today is undertaken in agroforestry systems in which some part of the natural forest is left in place.
Even so, shade production has considerable impact on the ecosystems where it is established. Biomass and soil fertility declined because of coca production in Nigeria (Ekanade 1987).
Specific impacts documented include losses of overall foliage cover (reduced by 6.9%), reduced height of native trees (a 58.6% reduction), reduction in tree girth (a 66.9% reduction), tree basal area (88.1% reduction), and volume of wood (95% reduction). Only tree density and accumulated litter showed a relative increase (by 78% and 2.6%, respectively) in cocoa plantations relative to natural forests.
Forest mammals, reptiles, and amphibians showed declines both in absolute numbers and species diversity similar to the deterioration of the vegetation matrix. What tends to happen is that some species disappear, and a small subset of species that do well in disturbed areas tend to dominate cocoa production forests.
In Brazil, even in the shade cocoa-planting system where seedlings are planted within native forests, the floral substrata are removed, as are about 90% of the original tree species. The impact on sedentary biodiversity can be devastating.
While clearing the understory and much of the forest canopy to plant shade cocoa has significant environmental impacts, experience and research have both demonstrated that sustainable shade cocoa production provides habitat to important forest and migratory bird and mammal species.
Sustainable shade cocoa production can play a strategic role in the preservation of forests, forest remnants, and forest corridors - those forested areas that connect larger blocks of intact forest (Knight 1998). Similarly, higher diversity within the cropping system has been found to lead to higher diversity in associated biota, as does lower use of pesticides.
Overall, increased biodiversity leads to more effective pest control and pollination. And finally, increased biodiversity leads to more efficient nutrient recycling (Whinney 2001).
