Beyond Flower Abundance: Plant Attractiveness Explains Patterns of Pollinator Visits at the Community‐Level
Leonardo Lorenzato, Andrea Della Bella, Edy Fantinato, Gabriella BuffaABSTRACT
Aims
Flower abundance is widely used to explain community‐level patterns of pollinator visitation. However, studies often report contrasting relationships between flower abundance and pollinator visits, suggesting that additional factors operating at the community‐level may modulate pollinator responses to flower abundance. In this study, we investigated whether incorporating measures of plant attractiveness at the community‐level can help explain contrasting patterns of pollinator visits in temperate and Mediterranean regions.
Location
Eastern Po Valley, north‐eastern Italy (45°43′ N–45°01′ N, 11°00′ E–12°14′ E).
Methods
We used 3 years of plant–pollinator interaction data collected in herbaceous semi‐natural areas. A comprehensive dataset was first used to quantify the relative contribution of selected floral traits (flower size, colour and shape) to species‐level visitation and to derive a species‐level Plant Attractiveness Index ( PAI ). This index was then integrated into community‐level analyses of two independent datasets to evaluate how accounting for plant attractiveness influences the relationship between flower abundance and pollinator visits.
Results
We showed that when flower abundance was analysed without accounting for species‐level attractiveness, the relationship with pollinator visits differed between years, showing either positive or hump‐shaped patterns. In contrast, weighting flower abundance by species‐level attractiveness revealed a consistent positive relationship.
Conclusions
Our findings contribute to explaining why previous studies have reported linear, hump‐shaped or negative flower–visitor relationships by showing that, once flower abundance is weighted by species‐level attractiveness, pollinator visitation follows a consistently positive relationship.