Data from: Landscape diversity moderates the effects of bee visitation frequency to flowers on crop production.

1.Reductions in natural habitat are implicated in declining honey bee Apis
mellifera L. and wild bee populations, thereby threatening crop
production. This concern has stimulated interest in identifying
landscape-level impacts on bee-mediated pollination services, but previous
studies have only inferred connections between landscape, bees and yield
through generalized linear regressions. 2. We examined landscape impacts
on bee-mediated crop yield using both a traditional linear regression
approach and conditional process modelling, which combined landscape
features, bee visits to crop flowers, interactions between landscape and
bee visits to flowers into a single model predicting crop yield. We used
the pumpkin Cucurbita pepo L. system in New York State and recorded bees
visiting pumpkin flowers in 2011 and 2012. Landscape diversity and
percentage of semi-natural grassland around each pumpkin field were
calculated. 3. Results from the traditional approach indicated that
landscape diversity, percentage of grassland in the landscape, bumble bee
Bombus impatiens Cresson, and honey bee visitation frequency each
positively predicted yield. A common conclusion from these results is that
pumpkins grown in highly diverse or high grassland coverage landscapes
would have greater yields via bumble bee and honey bee visits to flowers.
However, this inference does not preclude the possibility that landscape
features may be associated with crop yield, independent of bee visits to
flowers. 4. Results from conditional process modelling indicated that only
pumpkins grown in highly diverse landscapes were predicted to have greater
yields as a consequence of more bumble bee visits to pumpkin flowers. None
of the landscape features predicted greater fruit yields as a consequence
of more honey bee visits to pumpkin flowers. This novel analysis indicated
that traditional approaches may be misinterpreting the relationships among
these variables. 5. Synthesis and applications. Bumble bees benefited from
a diverse landscape and their visits to flowers positively impacted
pumpkin production. Conservation of a diverse landscape should be promoted
to support improved pumpkin production. Growers can use this information
to decide where to plant pumpkins to improve the potential for high
yields, to identify scenarios where landscape diversity could be
increased, and where supplementation with bees might be beneficial.