Landscape structure and farming management interacts to modulate pollination supply and crop production in blueberries

Pollination services are affected by landscape context, farming
management, and pollinator community structure, all of which impact flower
visitation rates, pollen deposition and final production. We studied these
processes in Argentina for Highbush Blueberry crops which depend on
pollinators to produce marketable yields.  We studied how land
cover and honeybee stocking influence the abundance of wild and managed
pollinators in blueberry crops, using structural equation modeling to
disentangle the cascading effects through which pollinators contribute to
blueberry fruit number, size, nutritional content and overall
yield.  All pollinator functional groups responded to landscape
changes at a spatial scale under 1000 m, and the significance or direction
of the effects were modulated by the field-level deployment of honeybee
hives.  Fruit diameter increased with pollen deposited, but
decreased with honeybee abundance, which, had indirect effects on fruit
acidity and sugar content. Honeybees had a positive effect on the number
of fruit produced by the plants and also benefited the overall yield (kg
plant-1) through independent effects on both the quality and quantity
components of fruit production. Synthesis and applications: Deployment of
beehives in blueberry fields can buffer, but not compensate for the
negative effects on honeybee abundance produced by surrounding large scale
none-flowering crops. Such compensation would require high-quality
beehives by monitoring their health and strength. The contribution of
honeybees to crop production is not equal across production metrics. That
is, higher abundance of honeybees increases the number of berries
produced, but at the cost of smaller and more acidic fruits, potentially
reducing market value. Growers must consider this trade-off between fruit
quantity and quality when actively managing honeybee abundance.