Enhancing gardens as habitats for flower‐visiting aerial insects (pollinators): should we plant native or exotic species?
Salisbury, A., Armitage, J., Bostock, H., Perry, J., Tatchell, M., & Thompson, K. (2015). Enhancing gardens as habitats for flower‐visiting aerial insects (pollinators): should we plant native or exotic species?. Journal of Applied Ecology, 52(5), 1156-1164. PDF.
Summary
It is generally thought by scientists and managers that native plants yield more biodiversity than non-native plants . As a result, restoration management plans often include native plantings as one mechanism to improve diversity in managed areas. However, Salisbury et al. (2015) argue that empirical support for this idea (i.e., diversity in native plantings > non-native plantings) needs better experimental support. As such, the authors set out to compare pollinator biodiversity on plots with native (originating from UK), near-native (non-native to UK, sourced from northern hemisphere), and non-native (non-native to UK, sourced from southern hemisphere) plantings over a 4-year period. They found that the diversity of pollinators was positively correlated with the abundance of floral resources regardless of source (native, near-native, or non-native). Although flowers were most important, Salisbury et al. found that pollinators (short-tongue bees, honeybees, and hoverflies) preferred native and/or near-native plantings over non-native plantings when both flower resources were available. However, the time of the growing season is important, and more pollinators were found on non-native plantings later in the season, which matched the peak flowering season for many non-natives. Therefore, future planting projects aimed at improving pollinator diversity should select a diverse array of native plant species that flower throughout the duration of the growing season.
Take home points
More floral resources will yield more pollinators
Pollinators preferred native and near-native plantings over non-native plantings except late in the season when non-natives tended to have more floral resources than native/near-native plantings
Management implications
When replanting for pollinators, the selection of floral resources is important. The more diverse floral resources, the better; however, species composition matters! Choose native species such that the plant community can produce flowers for the duration of the growing season.
Keywords
Impact Study; Observation; Invasive Plant; Terrestrial Habitat