Complementary crops and landscape features sustain wild bee communities

Abstract

Wild bees, which are important for commercial pollination, depend on floral and nesting resources both at farms and in the surrounding landscape. Mass-flowering crops are only in bloom for a few weeks and unable to support bee populations that persist throughout the year. Farm fields and orchards that flower in succession potentially can extend the availability of floral resources for pollinators. However, it is unclear whether the same bee species or genera will forage from one crop to the next, which bees specialize on particular crops, and to what degree inter-crop visitation patterns will be mediated by landscape context. We therefore studied local- and landscape-level drivers of bee diversity and species turnover in apple orchards, blueberry fields, and raspberry fields that bloom sequentially in southern Quebec, Canada. Despite the presence of high bee species turnover, orchards and small fruit fields complemented each other phenologically by supporting two bee genera essential to their pollination: mining bees (Andrena spp.) and bumble bees (Bombus spp.). A number of bee species specialized on apple, blueberry, or raspberry blossoms, suggesting that all three crops could be used to promote regional bee diversity. Bee diversity (rarefied richness, wild bee abundance) was highest across crops in landscapes containing hedgerows, meadows, and suburban areas that provide ancillary nesting and floral resources throughout the spring and summer. Promoting phenological complementarity in floral resources at the farmstead and landscape scales is essential to sustaining diverse wild bee populations.

Bee communities and pollination services in adjacent crop fields following flower removal in an invasive forest shrub

“…, Martins et al. , Drummond ). However, our results also suggest that flowering crops immediately adjacent to L. maackii flowers are less adequately pollinated.…”

Using citizen science to examine the nesting ecology of ground‐nesting bees

“…, Sardiñas and Kremen , Martins et al. ). When the species‐specific studies are taken together, it is clear that there may be significant interspecific diversity in solitary bee nest site preferences with regard to key environmental characteristics.…”

“…A recent study from Quebec, Canada, showed that bee diversity in apple orchards and blueberry and raspberry fields was influenced by the presence of suitable nesting resources (Martins et al. ). Again, the important characteristics of the nesting resource vary, but the availability of bare ground (Potts et al.…”

“…There are two main types of empirical study performed on ground-nesting bees' nesting ecology: those studies that focus on single species (Potts and Willmer 1997, Wuellner 1999, Julier and Roulston 2009, Xie et al 2013 and those that examine the effects of nest site suitability on wider metrics such as species richness, abundance, and community composition (Grundel et al 2010, Sardiñas and Kremen 2014, Martins et al 2018. When the speciesspecific studies are taken together, it is clear that there may be significant interspecific diversity in solitary bee nest site preferences with regard to key environmental characteristics.…”

“…Across geographical contexts, the availability of ground-nesting resources has been shown to be a strong predictor of bee abundance (Potts et al 2003, Sardiñas andKremen 2014), species richness (Grundel et al 2010), and community composition (Potts et al 2005, Grundel et al 2010. A recent study from Quebec, Canada, showed that bee diversity in apple orchards and blueberry and raspberry fields was influenced by the presence of suitable nesting resources (Martins et al 2018). Again, the important characteristics of the nesting resource vary, but the availability of bare ground (Potts et al 2005), sloped terrain (Sardiñas and Kremen 2014), sandy soils (Cane 1991), and soils with low organic matter content (Grundel et al 2010) are factors that have proven to be important in at least some contexts.…”