Data from: Trait-based effects of plant invasion on floral resources, hoverflies and bees

1. Plant invasions can lead to homogeneous communities with decreased
functional diversity. However, invasive plants, with various morphological
and phenological traits, may drive pollinator communities in a less
predictable, more complex way. They can promote pollinators compatible
with their floral traits while leaving others without foraging resources.
2. Our observational study on 10 invasive herbaceous species applied a
trait-based approach to investigate plant invasion-driven changes in
floral resources, hoverfly, and bee communities. We sampled invaded and
non-invaded (control) sites before and during the flowering of the
invasive plants. We analysed the differences in floral traits between
invasive and native plants, functional diversity, and trait distributions
of flower and pollinator communities between the invaded and control
sites. 3. Five invasive plant species differed from natives in floral
traits. Plant invasion caused species-specific changes in functional
diversity and trait distributions of communities. For instance, invaded
sites had a decreased functional diversity of hoverflies before flowering
of invasive species, and larger hoverflies during flowering of invasive
species compared with control sites. Smaller bees were associated with
invasive plants with shallow flowers, while larger and long-tongued bees
were associated with two invasive species with restricted floral access.
4. Similar to previous studies, pollinator traits showed mixed or neutral
responses to plant invasion. This is probably due to the high integration
capability of invasive plants into plant-pollinator systems, or
limitations in sampling, trait resolution, and unrevealed environmental
factors. We provide recommendations for future studies to better
understand the trait-based community composition of flowering plants and
pollinators.