Coffee and cacao pollination: Advances in ecological knowledge from tropical ecology

Although ecologists traditionally focus on natural ecosystems, there is growing awareness that managed systems provide a research environment for understanding basic ecological relationships on a large scale. Tropical agricultural landscapes are shaped by agroforestry systems ranging from traditionally-managed agroforests to shaded monocultures. In these landscapes, the diversity of organisms is manipulated by the farmer’s management decisions and the relationship between agricultural and other landscape elements. This offers the opportunity to study the importance of natural habitats for pollinators and their services in a landscape context. Here, we show how tropical agroforestry systems can be used to identify the mechanisms that influence species diversity and subsequent biotic interactions at different spatial scales. Our focus is on plants -coffee and cacao- and their pollinators, which are of basic ecological interest as partners in an important mutualistic interaction. We review how insect-mediated pollination services depend on local agroforest characteristics and on natural habitats in surrounding landscapes. Further, we evaluate the functional significance of pollinator diversity, the explanatory value of species traits, and provide an intercontinental comparison of coffee pollinator assemblages. We suggest that future research should use the potential of agroforestry to gain deeper insights into the interactions between plants and pollinators.