Landscape forest cover and regional context shape the conservation value of shaded cocoa agroforests for bees and social wasps

The expansion of agricultural lands threatens biodiversity maintenance across the tropics. Although some agroforestry systems may be biodiversity-friendly, their conservation value likely depends on the landscape and regional contexts in which they are embedded—a poorly tested hypothesis.

We assessed the conservation value of shaded cocoa agroforests for bees and social wasps, and evaluated whether such value depends on the remaining forest cover at the landscape and/or regional scales.

Using a paired design, we compared α- (species number) and β-diversity of each taxon between cocoa agroforests and neighbouring rainforests in 30 landscapes from three regions with different deforestation levels from the Brazilian Atlantic Forest. We assessed whether the species number ratio (cocoa/forest) and β-diversity related to landscape-scale forest cover, and whether such a relationship differed among regions (interacting effect).

Cocoa agroforests held more bee and wasp species than forests, and β-diversity between habitats was moderate (bees) to high (wasps). Bees’ species number ratio peaked at the intermediate-deforested region, and β-diversity decreased with increasing forest cover, indicating that both land uses shared more species in more forested landscapes, especially in the high- and intermediate-deforested regions. Yet, for social wasps, β-diversity varied only within regions, with habitats sharing more species in the low-deforested region.

Our findings highlight that the conservation value of shaded cocoa agroforests for bees and social wasps depends on local and regional landscape forest cover. With cocoa agroforest being highly permeable matrix which increases with higher forest cover especially for bees in high- and intermediate-deforested regions.