Floral spectral reflectance data for: Floral color properties of serpentine seep assemblages depend on community size and species richness

Functional traits, particularly those that impact fitness, can shape the
ecological and evolutionary relationships among coexisting species of the
same trophic level. Thus, examining these traits and properties of their
distributions (underdispersion, overdispersion) within communities can
provide insights into key ecological interactions (e.g., competition,
facilitation) involved in community assembly. For instance, the
distribution of floral colors in a community may reflect
pollinator-mediated interactions between sympatric plant species, and the
phylogenetic distribution of color can inform how evolutionary
contingencies can continue to shape extant community assemblages.
Additionally, the abundance and species richness of the local habitat may
influence the type or strength of ecological interactions among
co-occurring species. To evaluate the impact of community size and species
richness on mechanisms shaping the distribution of ecologically relevant
traits, we examined how floral color (defined by pollinator color vision
models) is distributed within co-flowering assemblages. We modeled floral
reflectance spectra of 55 co-flowering species using honeybee (Apis
mellifera) and syrphid fly (Eristalis tenax) visual systems to assess the
distributions of flower color across 14 serpentine seep communities in
California. We found that phylogenetic relatedness had little impact on
the observed color assemblages. However, smaller seep communities with
lower species richness were more overdispersed for flower color than
larger, more species-rich communities. Results support that competitive
exclusion could be a dominant process shaping the species richness of
flower color in smaller-sized communities with lower species richness, but
this is less detectable or overwhelmed by other processes at larger, more
speciose communities.