Integrating floral trait and flowering time distribution patterns help reveal a more dynamic nature of co-flowering community assembly processes

Species’ floral traits and flowering times are known to be the major
drivers of pollinator-mediated plant-plant interactions in diverse
co-flowering communities. However, their simultaneous role in mediating
plant community assembly and plant-pollinator interactions is still poorly
understood. Since not all species flower at the same time, inference of
facilitative and competitive interactions based on floral trait
distribution patterns should account for fine phenological structure
(intensity of flowering overlap) within co-flowering communities. Such an
approach may also help reveal the simultaneous action of competitive and
facilitative interactions in structuring co-flowering communities. Here we
used modularity within a co-flowering network context, as a novel approach
to detect convergent and/or over-dispersed patterns in floral trait
distribution and pollinator sharing. Specifically, we evaluate differences
in floral trait and pollinator distribution patterns within (high temporal
flowering overlap) and among co-flowering modules (low temporal flowering
overlap). We further evaluate the consistency of observed floral trait and
pollinator sharing distribution patterns across space (three geographic
regions) and time (dry and rainy seasons). We found that floral trait
similarity was significantly higher in plant species within co-flowering
modules than in species among them. This suggests pollinator facilitation
may lead to floral trait convergence, but only within co-flowering
modules. However, our results also revealed seasonal and spatial shifts in
the underlying interactions (facilitation or competition) driving
co-flowering assembly, suggesting that the prevalent dominant interactions
are not static. Synthesis: Overall, we provide strong evidence showing
that the use of flowering time and floral trait distribution alone may be
insufficient to fully uncover the role of pollinator-mediated interactions
in community assembly. Integrating this information along with patterns of
pollinator sharing will greatly help reveal the simultaneous action of
facilitative and competitive pollinator-mediated interactions in
co-flowering communities. The spatial and temporal variation in flowering
and trait distribution patterns observed further emphasize the importance
of adopting a more dynamic view of community assembly processes.