In their latest research, Jarrett and colleagues report the first in‐depth investigation into avian diversity and community composition in African cocoa farms, by assembling a dataset of 9,566 individual birds caught across 83 sites over 30 years in Southern Cameroon.
Cocoa, the primary ingredient in all our beloved chocolate products, is grown across the tropics using a range of agricultural practices.
Originating in the understory of Central and South American forests, cocoa trees can thrive in shady conditions. In West Africa, the region responsible for producing about 70% of the World’s cocoa, cocoa is often cultivated in low-intensity plantations called agroforests. Agroforestry is the practice of planting crop trees in amongst “shade trees”; these additional trees provide cover from the harsh tropical sun and other services such as fruit and timber production.
Recent efforts to increase cocoa yields have resulted in a push towards intensification of cocoa plantations into monocultures in many cocoa-producing areas.
Agroforestry: a win-win solution
Given the current climate of rainforest destruction and increasing agricultural demands, scientists and policymakers have turned to agroforestry in the hope that it can provide a win-win solution for both biodiversity conservation and agricultural production.
There are promising results showing that yields from agroforests are not compromised by biodiversity, possibly because of the services (e.g., pollination) provided by wildlife. With regards to biodiversity conservation, several studies from the Neotropics and tropical Asia have shown that agroforests can sustain high levels of biodiversity, including birds, ants and amphibians.
This biodiversity declines when farms are intensified into monocultures. However, though Africa is a major producer of cocoa worldwide, very little is known about biodiversity (especially of vertebrates) in African cocoa farms.
Birds in African cocoa farms
Fortunately, several research groups (both African and international) have been surveying birds in African cocoa farms and forest areas for over three decades. Combing the data collected by these groups resulted in records of more than 8,000 bird captures across a 30 year period.
With this valuable source of information we aimed to address the following questions a) What are the differences between bird communities in the forest and in cocoa farms? b) What is the effect of shade management (measured as % canopy cover) on bird communities in cocoa farms? And c) Does the composition of the landscape surrounding farms affect the bird communities inside them?
Overall, we found that African cocoa farms contained very diverse bird communities, about as diverse to those found in forest plots. However, whilst bird communities in forest plots were relatively consistent (similar species found in each plot), in cocoa farms, there was a lot of variation.
This variation between cocoa farms reflects, in part, the different ways in which farms are managed; our study sites ranged from low-intensity farms with nearly 100% canopy cover to intensively managed farms with ~20% canopy cover. Birds in these farms were affected by their management practices.
Our results indicate that sensitive forest species and species with specialised diets (e.g., ant-following birds that specialize on tracking driver ant swarms) were much less common in sunny farms compared with shady ones. In contrast, frugivorous species were more common in sunny farms, possibly due to the common practice of planting fruit trees amongst cocoa trees in intensively managed farms.
Additionally, we found that cocoa farms in landscapes with a lot of forest cover (e.g., cocoa farms in villages near rainforest reserves) had higher numbers of sensitive species.
What it all means
The results from our study indicate that shady cocoa farms in Africa can serve as habitat for a fair number sensitive rainforest bird species. There is no substitute for primary rainforest, however, as many of the most specialized birds species were lost even in the shadiest farms. On the other hand, intensive sunny monocultures cannot accommodate hardly any sensitive rainforest species.
We also show that it is important to maintain areas of forest on the landscape (e.g., forest reserves or protected areas), as farms with forest nearby had higher numbers of forest species compared with farms in very degraded landscapes.
These findings are the first steps towards making cocoa production in Africa more wildlife-friendly. However, many questions remain unanswered, such as the relationship between biodiversity and yield in African farms, and the effect of other management practices (e.g., application of chemicals) on bird communities.
If policymakers want to prevent extreme deforestation and biodiversity loss in one of the world’s diversity hotspots, they should actively encourage ecologically sustainable agricultural practices such as shaded cocoa agroforestry that employs science‐based management.
Read the full Open Access paper Bird communities in African cocoa agroforestry are diverse but lack specialized insectivores in Journal of Applied Ecology.