DOI: 10.5061/dryad.v41ns1rtq
title: Floral spectral reflectance data for: Floral color properties of serpentine seep assemblages depend on community size and species richness

description: 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.
description: Spectra were collected using either an internal pulsed-xenon
 light source (Jaz, Ocean Optics, Dunedin, FL USA) or a deuterium-halogen
 light source (DH-2000-BAL (Ocean Optics, Dunedin, FL USA) with a
 Spectralon white standard (Labsphere, North Sutton, NH) and dark
 correction to measure percent reflectance from 300-700 nanometers, which
 is the general range of color perception by many flower-visiting insects,
 including bees and flies.  Floral tissue was illuminated with a collimated
 beam oriented normal to the floral surface, and spectra were collected by
 a probe positioned at a 45-degree azimuth, composed of a collimating lens
 and optical fiber (fiber diameter = 400 microns) connected to the
 spectrophotometer. We utilized SpectraSuite version 2.0.162 software for
 capturing spectral data (Ocean Optics, Dunedin, FL USA). Spectra were
 collected with an integration time ranging from 50-250 milliseconds, a
 boxcar smoothing width ranging 3-25 nanometers, and with a range of 10-30
 average spectral scans (species-specific details of these parameters are
 included in datasheet). In collection of floral spectra, at least one
 single petal of the floral unit was measured for each flowering species,
 or in the instance that a single petal was too small to cover the entire
 sampling area, multiple petals were overlaid to provide enough surface for
 the spectrometer to collect a reflectance reading. Within each floral
 unit, if there was a noticeable change in coloration in the human vision
 color spectrum or morphological component (e.g.: petal v. labellum),
 reflectance readings were obtained from various portions across the floral
 unit. We also searched for any change in ultraviolet reflectance range
 across the floral display area by viewing live spectrometer reflectance
 output while moving across the floral tissue surface.  Any noted
 differences within a floral unit for each species is included in
 datasheet.
description: Legend (also included in datasheet header)
 -- 'filename': code for specific spectral file;
 'species': plant species;
 'Internal_contrast_estimated': whether internal contrast was
 estimated for species; 'Internal_contrast_detail': detailed
 location of spectra collection on floral unit; 'spectrometer':
 spectrometer model (USB2000+ , USB4000, Jaz, Ocean Optics, Dunedin, FL
 USA); 'integration_time_microseconds': given in microseconds
 (range of 50-250 milliseconds, which is 50,000-250,000 microseconds);
 'number_spectra_averaged': ranges from 10-30 scans;
 'boxcar_smoothing_width': ranges 3-25 nanometers;
 'number_pixels_processed': number of pixels processed per
 spectral measurement; 'columns at 300-700': binned reflectance
 values as percentages (%), binned to 1-nm intervals;