The phenology of vegetation, namely leaf-out and senescence, can influence the Earth’s climate over regional spatial scales and long time periods (e.g., over 30 years or more), in addition to microclimates over local spatial scales and shorter time periods (weeks to months). However, the effects of flowers on climate and microclimate are unknown. We investigate whether flowers can influence light reflected by the land surface and soil microclimate in a subalpine meadow. We conducted a flower removal experiment with a common sunflower species, Helianthella quinquenervis, for 3 years (2015, 2017, and 2019). The flower removal treatment simulates the appearance of the meadow when Helianthella flowers earlier under climate change and loses its flowers to frost (other plant structures are not damaged by frost). We test the hypotheses that a reduction in cover of yellow flowers leads to a greener land surface, lower reflectance, warmer and drier soils, and increased plant water stress. Flower removal plots are greener, reflect less light, exhibit up to 1.2 °C warmer soil temperatures during the warmest daylight hours, and contain ca. 1% less soil moisture compared to controls. However, soils were warmer in only 2 of the 3 years, when flower abundance was high. Helianthella water use efficiency did not differ between removal and control plots. Our study provides evidence for a previously undocumented effect of flowers on soil microclimate, an effect that is likely mediated by climate change and flowering phenology. Many anthropogenic environmental changes alter landscape albedo, all of which could be mediated by flowers: climate change, plant invasions, and agriculture. This study highlights how further consideration of the effects of flowers on land surface albedo could improve our understanding of the effects of vegetation on microclimate.

These data were collected in a subalpine meadow near the Rocky Mountain Biological Laboratory.  See Iler et al. (in press at International Jounral of Biometeorology), DOI: 10.1007/s00484-021-02159-0, for details of experimental design and data collection. 

This dataset is associated with a paper titled: Can flowers affect land surface albedo and soil microclimates?  There are separate datafiles for the following responses: peak Helianthella flower abundance across the three years of the study (2015, 2017, 2019), weekly Helianthella flower counts during the flowering period, NDVI, reflectance of flower petals vs. leaves measured in the laboratory, reflectance of plots with and without flowers measured in the field, soil temperature in plots with and without flowers (files for 2015, 2017, and 2019), soil moisture for plots with and without flowers (files for 2015, 2017, and 2019), light data measured from HOBO data loggers (2015, 2017, and 2019), and two measures of water stress in Helianthella (delta C13 and pressure required to extract water from a leaf).  All of these files are used in an uploaded R script to analyze the data (HeQu Albedo Analysis_CLEAN_2020.R), and the files and variables are described in a Word metadata file.