Data from: Plant species richness and sunlight exposure increase pollinator attraction to pollinator gardens

Evidence documenting the decline of insect populations is accumulating.
Efforts have increased to mitigate pollinator losses by establishing
gardens to support pollinator diversity. However, knowledge of the
specific garden characteristics, landscape features and environmental
factors that affect pollinator diversity and abundance is limited,
particularly in biodiverse regions in North America. In order to better
understand how garden characteristics affect pollinator attraction, we
compared pollinator composition across 16 pollinator gardens in the
Appalachian ecoregion in North America. We evaluated the effects of garden
characteristics (e.g., plant richness, flower abundance, garden size,
proportion of native species), landscape features (land-use type, distance
to forest) and environmental factors (sunlight exposure) on pollinator
richness, overall visitation rate and visitation rate by defined
pollinator groups (i.e., solitary native bees, bumblebees, honeybees,
lepidopterans and other insects). Solitary bees (i.e., native bees besides
Bombus) were the most frequent visitors (61%). We found differences in
pollinator species composition between urban and rural gardens. Moreover,
plant richness had a positive effect on pollinator richness and an
increase in flower abundance increased pollinator visitation rate. Flower
abundance, plant richness and high sunlight exposure increased visitation
rate of solitary bees. Visitation rate of solitary bees however, decreased
with increasing proportion of native plants. Overall, our results indicate
that garden characteristics, landscape and environmental factors all are
important mediators of pollinator diversity and abundance. Solitary bees
were most affected by garden (i.e., plant richness, number of flowers,
proportion of native plants) and environmental factors (i.e., sunlight
exposure). However, we also identified differential effects of garden and
environmental factors across pollinator groups. We suggest that an
integrated management approach that considers multiple garden and
environmental characteristics could help improve the effectiveness of
pollinator garden as a conservation tool and help preserve this key
ecosystem service.