Pollinator diversity and interactions in sub-saharan smallholding farms

Sub-Saharan African agriculture largely relies on smallholding farms that provide access to food and economical income to the local population. In this context, crop yield is largely susceptible to variations related to pollination and the unceasing soil-use conversion into urban and agricultural landscapes is reducing the stability and provision of this and other ecosystem services. This scenario is more and more enhancing the need for a deeper comprehension of the effects that landscape intensification poses to pollination ecologyissues, a research topic that is largely neglected in Sub-Saharan countries. In this study, we evaluated how landscape characteristics and flower resource availability in the surrounding of smallholding farms affect plant-pollinator communities and interactions in NorthernTanzania. By combining field monitoring, pollen ITS2 DNA metabarcoding, land use and interaction network analysis, we found that plant-pollinator systems are largely affected by landscape intensification. Pollinator species richness and abundance were found todecrease in farms surrounded by higher amounts of impervious surface cover, whereas individuals' niche overlap increases with impervious and agricultural cover. Plant resource availability acts on pollinator insects by reducing individuals' niche overlap and increasingtheir abundance that, in turn, improves network generalization and the overall stability of the observed interaction networks. Based on these results, we concluded that reliable management strategies to maintain richer and healthier pollinator communities in this farming context should be aimed at i) improving the availability of greenspaces in urbanlandscapes to reduce the pressures posed by urbanization, ii) preserving semi-natural patches in rural landscape and iii) integrating these measures with local scale interventions on plants communities to improve the availability of flower resources for insects.