Prolonged blooming season of flower plantings increases wild bee abundance and richness in agricultural landscapes

Abstract

Flower plantings can increase the abundance of bees and improve pollination services in the surrounding landscape. However, uncertainty remains as to whether flower plantings play a role in wild bee conservation. The aim of this study has been to examine the contribution of the composition and management of flower plantings to the attraction of bees, particularly of endangered species. In a large-scale monitoring project, wild bee data were collected on 60 flower plantings and 120 semi-natural reference plots in 20 study sites over 2 years. In total, we recorded 60,335 bees belonging to 351 species. In flower plantings, bee species richness and abundance were intricately linked to high plant richness and constant blooming throughout the season. In the first year of this study, a complimentary blooming phenology of annual and perennial plants resulted in a more constant bloom on flower plantings. In the second year, partial mowing of flower plantings mid-season enhanced floral resources during the late season. As a result, bee richness and abundance in flower plantings increased from the first to the second year. Nevertheless, the compositional heterogeneity of bees over all 20 sites in Germany did not increase from the first to the second year. We conclude that diverse and constant blooming throughout the season is the most important factor for promoting bees in flower plantings. To ensure sufficient beta diversity over a large spatial scale, we recommend the adjustment of seed mixtures according to the geographical region.

Effects of farmland consolidation in southern China on wild bee species composition, nesting location and body size variations

“…Another possible reason relates to the studied mass‐flowering crop, oilseed rape. This crop provides easily accessible food (pollen and nectar) for wild bees in the sampling period across the different landscapes (Beyer et al, 2021; Neumueller et al, 2021) that could be so attractive that it temporarily effectively draws in a great number of insect pollinators from across the various species present in different parts of the wider agricultural landscape (Shaw et al, 2020).…”

Artificial Nesting Hills Promote Wild Bees in Agricultural Landscapes

“…They were sown with a mixture of regionally native, naturalized, and cultured (non-invasive) plant species. A detailed methodology describing the establishment of the flower plantings is given in [ 28 ]. In each of the described habitat types, three sampling plots of 0.3 ha were established, resulting in a total of 180 reference plots.…”

“…Each plot was sampled in two subunits of 25 min, one before and one after midday, to account for any intra-day phenologies of bees. Bee data from 2019 were taken from [ 28 ].…”

Between perfect habitat and ecological trap: even wildflower strips mulched annually increase pollinating insect numbers in intensively used agricultural landscapes

“…Great importance was attached to not taking any individuals from nature as long as they could be reliably identified in the field (by sight or by temporary capture). In the case of wild bees, the same approach was followed as in the BienABest project (Neumüller et al 2020(Neumüller et al , 2021.…”