A
new observational study on 10 invasive plant species, published in
Insect Conservation and Diversity, explores the trait-based effects of plant invasion on functional diversity and floral resources, hoverfly and bee communities.
To investigate this relation, the researchers conducted field studies in Hungary and Romania and collected samples of pollinators and floral resources from invaded and non-invaded sites before and during the flowering of the invasive plants. A statistical analysis of the sampling and a multilevel method to assess the effect of invasion on trait-abundance relationships showed that in invaded sites the functional diversity, size and flight time of pollinators seems to be influenced by the differences in floral morphological and phenological traits between invasive and native plant species.
More specifically, 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 invasive plants with deeper flowers. The study confirms previous research findings that pollinator traits have mixed or neutral responses to plant invasion.
To better understand the trait-based community composition of flowering plants and pollinators, researchers provide recommendations for more case studies on a wider scale of invasive plants, more effort in data gathering and analysis, as well as meta-analytical syntheses.
Read the full paper here.
Graphical abstract: Results of floral trait dissimilarity (inner sector of the circle), functional diversity (middle sector), and multilevel method, assessing the invasion–trait–community relationships (outer sector) for floral resources (green), hoverflies (orange) and wild bees (blue), separately for the two sampling periods.