Indirect interactions between pollinators drive interaction rewiring through space

In recent years, an extended body of literature has focused on the importance of either temporal or spatial dynamics in shaping the structure of interacting plant and pollinator communities. This improvement from a previously static and aggregated perspective has allowed us to understand many of the ecological processes that shape community assembly. However, fewer are the studies that have simultaneously focused on spatial and temporal dynamics, and even fewer are those that collect data across different habitat types to assess the generality of their findings. Here, we used a dataset collected weekly throughout the full flowering season for two consecutive years and within two contrasting habitat types in N and SW Spain: a mountain grassland area and the understory of sparse pine forests. We evaluated species and interaction persistence through space and time, pollinator fidelity, and turnover patterns in interaction composition while providing a potential mechanistic explanation for the patterns observed. Our results show that although species generalization does not explain species or interaction persistence, moderately generalist species are those showing the greatest fidelity to the subset of plant species they visit through space and time. Further, we find that interaction turnover through time is mostly driven by changes in species composition, while through space it is mostly driven by interaction rewiring resulting from indirect competitive interactions between pollinator species. Our results help to shed light on the potential mechanisms driving community assembly patterns beyond niche or neutral processes by adding within-trophic-level interactions that can modify pollinator preferences.

Automated summary

In recent years, research has focused on the importance of temporal and spatial dynamics in shaping plant and pollinator communities. However, few studies have simultaneously examined these dynamics and collected data across different habitat types. This study used a dataset collected in two contrasting habitat types over two years to evaluate species and interaction persistence, pollinator fidelity, and turnover patterns in interaction composition. The results suggest that moderately generalist species show the greatest fidelity to the subset of plant species they visit through space and time, and that interaction turnover is driven by changes in species composition and indirect competitive interactions between pollinator species. These findings contribute to our understanding of community assembly patterns beyond niche or neutral processes.