Local and landscape-scale agricultural intensification is a major driver of global biodiversity loss. Controversially discussed solutions include wildlife-friendly farming or combining high-intensity farming with land-sparing for nature. Here, we integrate biodiversity and crop productivity data for smallholder cacao in Indonesia to exemplify for tropical agroforests that there is little relationship between yield and biodiversity under current management, opening substantial opportunities for wildlife-friendly management. Species richness of trees, fungi, invertebrates, and vertebrates did not decrease with yield. Moderate shade, adequate labor, and input level can be combined with a complex habitat structure to provide high biodiversity as well as high yields. Although livelihood impacts are held up as a major obstacle for wildlife-friendly farming in the tropics, our results suggest that in some situations, agroforests can be designed to optimize both biodiversity and crop production benefits without adding pressure to convert natural habitat to farmland.agroecosystems | ecosystem services | ecology-economy trade-offs | endemic species richness | shade trees

Mutualistic biotic interactions as among flowering plants and their animal pollinators are a key component of biodiversity. Pollination, especially by insects, is a key element in ecosystem functioning, and hence constitutes an ecosystem service of global importance. Not only sexual reproduction of plants is ensured, but also yields are stabilized and genetic variability of crops is maintained, counteracting inbreeding depression and facilitating system resilience. While experiencing rapid environmental change, there is an increased demand for food and income security, especially in sub-Saharan communities, which are highly dependent on small scale agriculture. By combining exclusion experiments, pollinator surveys and field manipulations, this study for the first time quantifies the contribution of bee pollinators to smallholders’ production of the major cash crops, cotton and sesame, in Burkina Faso. Pollination by honeybees and wild bees significantly increased yield quantity and quality on average up to 62%, while exclusion of pollinators caused an average yield gap of 37% in cotton and 59% in sesame. Self-pollination revealed inbreeding depression effects on fruit set and low germination rates in the F1-generation. Our results highlight potential negative consequences of any pollinator decline, provoking risks to agriculture and compromising crop yields in sub-Saharan West Africa.

Aim  Owing to their role as insect predators, web‐building spiders can be important biological control agents within agricultural systems. In complex tropical agroecosystems such as agroforests, management determines plant architecture, vegetation composition and associated ant density, but little is known on how these attributes, together with landscape context, determine spider web density. We hypothesized that all three spatial scales and the presence of Philidris ants significantly contribute to the explanation of spider web density with web types being differently affected.Location  In 42 differently managed cacao agroforestry systems in Sulawesi, Indonesia.Methods  We surveyed the distribution of five spider‐web types on 420 cacao trees to determine how these relate to habitat variables and a numerically dominant ant species at three different spatial scales, comparing tree, plot and landscape features. We fitted linear mixed‐effects model, selected the best model subset using information‐theoretic criteria and calculated the model‐averaged estimates. We used non‐metric multidimensional scaling (NMDS) to determine and visualize guild level responses to the effects of the tree, plot and landscape‐scale variables.Results  The five spider guilds preferred different features of cacao tree architecture. Most frequently recorded webs belonged to the line‐ and orb‐web type. At the tree scale, overall web density was positively related to canopy openness. At the plot scale, a higher number of shade trees was related to a higher web density. At the landscape scale, the altitude determined the distribution patterns of web‐building spiders. Presence of Philidris ants was positively associated with density of orb webs, while no pattern was found for other web types.Main conclusions  Results suggest spider web density could be increased by pruning of cacao trees while keeping shade trees at high density in cacao plots. The results emphasize the need to consider scale dependency of crop management and web‐guild‐specific responses that may be related to different functional roles of spiders as a high‐density predator group in agroforestry.

All over the world, pollinators are threatened by land‐use change involving degradation of seminatural habitats or conversion into agricultural land. Such disturbance often leads to lowered pollinator abundance and/or diversity, which might reduce crop yield in adjacent agricultural areas. For West Africa, changes in bee communities across disturbance gradients from savanna to agricultural land are mainly unknown. In this study, we monitored for the impact of human disturbance on bee communities in savanna and crop fields. We chose three savanna areas of varying disturbance intensity (low, medium, and high) in the South Sudanian zone of Burkina Faso, based on land‐use/land cover data via Landsat images, and selected nearby cotton and sesame fields. During 21 months covering two rainy and two dry seasons in 2014 and 2015, we captured bees using pan traps. Spatial and temporal patterns of bee species abundance, richness, evenness and community structure were assessed. In total, 35,469 bee specimens were caught on 12 savanna sites and 22 fields, comprising 97 species of 32 genera. Bee abundance was highest at intermediate disturbance in the rainy season. Species richness and evenness did not differ significantly. Bee communities at medium and highly disturbed savanna sites comprised only subsets of those at low disturbed sites. An across‐habitat spillover of bees (mostly abundant social bee species) from savanna into crop fields was observed during the rainy season when crops are mass‐flowering, whereas most savanna plants are not in bloom. Despite disturbance intensification, our findings suggest that wild bee communities can persist in anthropogenic landscapes and that some species even benefitted disproportionally. West African areas of crop production such as for cotton and sesame may serve as important food resources for bee species in times when resources in the savanna are scarce and receive at the same time considerable pollination service.

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Vegetable production in urban gardens of Ouagadougou contributes to food security, but water for irrigation is often of low quality. This is particularly acute if irrigation water is taken from wastewater polluted channels. This study aimed at (i) verifying to what degree irrigation water quality is correlated with contamination of lettuce with Escherichia coli, total coliforms, and Salmonella spp., and (ii) assessing effects of post-harvest handling on pathogen development during the trade chain. We tested pathogen removal efficiency on lettuce by applying post-harvest washing. Irrigation water of production areas in Ouagadougou (n = 10) showed a mean E. coli load of 2.1 × 105 CFU 100 mL−1. In 60% of the cases, irrigation water did not meet the standards of the World Health Organization (WHO) for safe irrigation water, and in 30% of the cases, irrigation water was contaminated with Salmonella spp. Loads of total coliforms on lettuce leaves ranged from 2.9 × 103 CFU g−1 to 1.3 × 106 CFU g−1, while E. coli averaged 1.1 × 102 CFU g−1. Results on post-harvest handling revealed that microbial loads increased along the trade chain. Overall, half of all lettuce samples (n = 60) were tested positively for Salmonella spp. The experiment showed that appropriate post-harvest handling could prevent the increase of total coliforms.

SummaryThe need to capture primary production in order to sustain and improve economic livelihoods has lead to increasing conversion of natural habitat and intensification of agricultural practices in many parts of the world including most tropical regions. Understanding how these processes affect ecosystems and their functioning, in particular in the high-diversity ecosystems of the tropics, has become a key issue in ecological research. In this chapter, our focus is on the agriculture-forest landscapes of Central Sulawesi, Indonesia, an island widely known for its endemic yet still poorly known flora and fauna. The rise of the region to one of the largest cacao producing areas in the world is at the core of recent land-use change and intensification processes. Covering plants (trees, rattan palms, herbs, bryophytes) and several invertebrate (ants, dung beetles, cacao insect herbivores, fruit-feeding butterflies, parasitic Hymenoptera, spiders) and vertebrate groups (amphibians, birds, murids, reptiles), we give an in-depth overview of the determinants of biodiversity in cacao landscapes, including both management and landscape-scale variables into our analyses. Results show that shaded agroforests host a rich community of species. By adopting a large-scale study design we showed that proximity of natural forest is a key predictor for species richness of plants, invertebrates and vertebrates alike. Endemics and forest specialists benefit most from indigenous shade tree cover and proximity to natural forest. Importantly, several functionally important groups such as insectivorous and seed-dispersing birds benefit from tall shade trees, shade tree diversity and proximity to forest edge, while parasitoid diversity is greatest close to natural forests. Available data on the effects of landuse change in cacao landscape of Central Sulawesi is increasing. Change in landscape configuration and management practices are being clearly reflected in the composition of species communities, with likely impacts on ecosystem services such as pest control and pollination. More knowledge is needed especially in terms of species interactions and ecosystem functioning, but also on how existing knowledge can contribute to effective conservation in human-dominated landscapes outside protected areas.

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