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There is a global concern of pollinator declines and linked ecosystem service losses. However, although land-use changes are a primary threat to biodiversity, how land-use change affects pollinator communities, pollination networks and fruit-set of food crops is poorly understood. The impact of land-use changes is especially understudied in tropical systems, even though most tropical crops are highly dependent on animal pollination. Using 40 sites to investigate diurnal and nocturnal flower visitors in small-scale agroecosystems across land-use gradients in Thailand and tropical South-western China, we show that habitat structure shapes pollinator communities at local (floral species richness) and landscape level (percentage of tree plantation in a 500 m radius and percentage forest in a 5 km radius), influencing both the species richness of pollinators and their visitation rates. These, in turn, alter plant-pollinator network structure: community-level specialization increases with floral species richness and percentage of forest cover. However, the specialization decreases with percentage of tree plantation, illustrating that natural habitat better supports specialized species. Furthermore, fruit-sets of several crops were affected by land-use. Notably, fruit-set of mango was positively associated with the percentage of forest cover in the surrounding landscape. These findings reveal how land-use influence pollinator communities and highlight how natural habitats may safeguard ecosystem services. • The local floral species richness and land-use type influence the pollinator communities. • Habitat structure change crop production in tropical small-holder agroecosystems. • Pollinator specialization increases with floral species richness and percentage of forest cover. • Mango fruit set was positively associated with the percentage of forest cover in the surrounding landscape. [ABSTRACT FROM AUTHOR]

Farmland birds are declining globally due to anthropogenic activities, with particularly few studies in Asian agricultural landscapes. Various studies have examined the impacts of landscape heterogeneity on farmland bird composition, but few have considered seasonal changes in bird diversity and examined functional feeding guild assemblages. Here, we disentangle the impact of seasonal variation (summer, monsoon, and winter), cropping practice (mixed crop, monocultural-crop, and fallow land), crop type (rice, wheat, maize, sugarcane, and other crops), landscape heterogeneity, and the number of houses and trees on the richness and abundance of farmland birds and their feeding guilds conducted within human-dominated agricultural landscapes of lowland Nepal. We established 116 transects (farmland = 100, forest = 8, and river = 8), and each transect was visited nine times from April 2018 to December 2019, with forests and river transect to test the dissimilarities in bird composition between those habitats and farmlands. We recorded 201 bird species in farmland, 133 in the forest, and 131 in river habitats. Bird composition on farmlands showed more dissimilarity with forest than river transects. We recorded nine globally, and 26 nationally threatened birds in farmlands. Seasonal variation and cropping practice significantly influenced the richness of all farmland birds and resident birds only, whereas species abundances vary by season only. We recorded higher species richness in the winter season and mixed crop fields but greater abundance in the monsoon and monoculture crop fields. Farmland bird richness increased with increasing tree numbers but decreased with increasing house numbers. Sugarcane fields had the highest bird richness within crop species, whereas rice fields had the greatest abundance. Seasons and cropping practice also shaped the assemblages of feeding guilds differently. In the context of increasing crop intensification globally, our study suggests that the governments in this region should encourage farmers to cultivate mixed crops and simultaneously restrict the urbanization of farmlands to protect bird diversity. Seasonality should be factored into analyses aimed at understanding bird diversity in agricultural landscapes. • We studied seasonal bird community composition in agricultural landscapes of lowland Nepal. • Mixed crop fields host higher bird richness whereas monoculture crop fields host higher abundance of farmland birds. • Number of trees positively influences richness of farmland birds, whereas number of houses has a negative impact. • Seasonal variation is an important parameter to shape the composition of farmland birds. [ABSTRACT FROM AUTHOR]