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Agricultural intensification is a major driver of wild bee decline. Vineyards may be inhabited by plant and animal species, especially when the inter‐row space is vegetated with spontaneous vegetation or cover crops. Wild bees depend on floral resources and suitable nesting sites which may be found in vineyard inter‐rows or in viticultural landscapes. Inter‐row vegetation is managed by mulching, tillage, and/or herbicide application and results in habitat degradation when applied intensively. Here, we hypothesize that lower vegetation management intensities, higher floral resources, and landscape diversity affect wild bee diversity and abundance dependent on their functional traits. We sampled wild bees semi‐quantitatively in 63 vineyards representing different vegetation management intensities across Europe in 2016. A proxy for floral resource availability was based on visual flower cover estimations. Management intensity was assessed by vegetation cover (%) twice a year per vineyard. The Shannon Landscape Diversity Index was used as a proxy for landscape diversity within a 750 m radius around each vineyard center point. Wild bee communities were clustered by country. At the country level, between 20 and 64 wild bee species were identified. Increased floral resource availability and extensive vegetation management both affected wild bee diversity and abundance in vineyards strongly positively. Increased landscape diversity had a small positive effect on wild bee diversity but compensated for the negative effect of low floral resource availability by increasing eusocial bee abundance. We conclude that wild bee diversity and abundance in vineyards is efficiently promoted by increasing floral resources and reducing vegetation management frequency. High landscape diversity further compensates for low floral resources in vineyards and increases pollinating insect abundance in viticulture landscapes.

Green roofs are potentially valuable habitats for plants and animals in urban areas. Wild bees are important pollinators for crops and wild plants and may be enhanced by anthropogenic structures, but little is known about wild bees on green roofs in cities. This study investigates the effects of green roof qualities (floral resources, substrate character and depth, roof height and age) on wild bee diversity, abundance and traits (nesting type, sociality, pollen specialisation, body size) on green roofs in Vienna. Nine green roofs were sampled monthly between March and September 2014 by a semi quantitative approach. Wild bees were collected in pre-defined sub-areas for the same amount of time and floral resources were recorded. Over all green roofs, 992 individuals belonging to 90 wild bee species were observed. Wild bee diversity and abundance was strongly positively affected by increasing forage availability and fine substrates. Wild bees on roofs were characteristically solitary, polylectic and 8.3-11.2 mm. Regarding nesting type, the percentage of above-ground nesting bees was higher compared to the common species composition in Middle Europe. Ground-nesting wild bees were mainly eusocial, smaller (6.4-9.6 mm) and positively affected by roofs with fine substrates. During June, when forage availability by wildflowers on roofs was Blow^(5-15% flower coverage), flowering Sedum species were an important forage resource. We conclude that wild bee diversity and abundance on green roofs are enhanced by floral resources. Furthermore, the installations of areas with finer and deeper substrates benefit ground nesting and eusocial wild bees.

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