Data for: Wild bee communities benefit from temporal complementarity of hedges and flower strips in apple orchards

1. Wild bees importantly pollinate both crop and wild plants. Yet, in
intensive agricultural landscapes, wild bees are rare due to resource
limitations of nectar and pollen. Flower strips and hedges are often used
as resource enhancements for wild bees to overcome this shortage, but
provide floral resources only during specific time periods. To sustain
diverse and stable bee communities, bee-attractive flowers need to be
available during the entire growing season. This may be achieved by
combining flower strips and hedges to complement each other and provide
continuous floral resources. 2. Over three subsequent years, we compared
the phenology of flower and wild bee communities in perennial flower
strips, hedges and improved hedges (complemented with a sown herb layer)
in conventional apple orchards in Southern Germany, a
pollination-dependent crop-system. 3. Hedges provided floral resources in
the early season while the flower strips took over later in the season. 4.
Bees visited the hedges mostly from March to June, whereas they visited
the flower strips from June to August (first year), and in the second year
already from April onwards. Flower strips were visited with an overall
higher abundance and species richness than the improved and not modified
hedges. 5. Synthesis and application: For enhancing wild bees in intensive
apple orchards, hedges and perennial flower strips are complementary in
providing flower resources. Yet, flower strips bloom more constantly and
during periods of flower scarcity, and thus attract more bees than hedges.
Perennial flower strips of different age classes should be preferred over
annual strips, at best in a network with some well-maintained hedges, as
perennial flower strips of different age attract different bee communities
and thus potentially a higher bee diversity on the landscape level.