DOI: 10.5061/dryad.jh9w0vtmh
title: Greater deviation in daily temperature from historic normals translates to shorter durations of reproductive spring phenophases for understory plants

description: As plants continue to respond to global warming with phenological shifts,
 our understanding of the importance of extreme, but short-lived, heat
 events has lagged relative to our understanding of plant responses to
 broad shifts in mean climate conditions. Here, we explore the importance
 of extreme daily temperatures in driving phenology across fourteen species
 of spring-flowering woodland herbs spanning a broad geographic range. We
 uniquely harnessed the combined power of community science and public
 gardens, engaging more than 30 volunteers to monitor 198 individual plants
 biweekly across five botanic gardens in the midwestern and southeastern
 U.S. We tested two hypotheses. First, that the duration of individual
 phenophases would be shortened by high daily temperatures relative to the
 30-year historical means (1991-2020). Second, these durations would vary
 among species. Our findings support both hypotheses. We observed
 significant inverse relationships between higher positive deviations of
 daily temperature from historic conditions, and the duration of three
 reproductive phenophases: ‘First Bud,’ ‘First Ripe Fruit,’ and ‘Early
 Fruiting’. Similar, though non-significant, trends were noted for several
 other early season phenophases. Additionally, significant differences in
 mean phenophase durations were detected among the different species,
 though these differences were inconsistent across plant parts (vegetative,
 flowering, fruiting).  Synthesis. Results underscore the
 sensitivity of reproductive plant phenophases to short-term extreme daily
 temperatures relative to historic means early in the growing season. This
 suggests that climate change, characterized by increasing frequency and
 intensity of temperature extremes, could induce rapid and potentially
 disruptive shifts in the phenology of spring wildflowers. The inclusion of
 multiple species and geographically distinct locations permits broad
 generalization of the results across North American spring-flowering
 understory herbs in various environments. The methodology (fine-scale
 temporal monitoring of phenology by community scientists) is widely
 applicable and could be adopted by public gardens globally to enhance our
 understanding of climate change impacts while simultaneously engaging with
 the public.
description: This dataset was collected by trained public volunteers at 5
 botanical gardens/arboreta (Chicago Botanic Garden, Glencoe, IL; Holden
 Arboretum, Kirtland, OH; Missouri Botanical Garden, St. Louis, MO; Dawes
 Arboretum, Newark, OH; Huntsville Botanical Garden, Huntsville, AL) from
 March - October 2023. The data are observations of phenology (i.e., stage
 of phenology or 'phenophase') recorded by volunteers on a
 twice-weekly basis using the Chicago Botanic Garden smartphone app
 'Budburst.'
description: # Greater deviation in daily temperature from historic normals translates
 to shorter durations of reproductive spring phenophases for understory
 plants
 [https://doi.org/10.5061/dryad.jh9w0vtmh](https://doi.org/10.5061/dryad.jh9w0vtmh) ## Description of the data and file structure This dataset was collected by trained public volunteers at 5 botanical gardens/arboreta (Chicago Botanic Garden, Glencoe, IL; Holden Arboretum, Kirtland, OH; Missouri Botanical Garden, St. Louis, MO; Dawes Arboretum, Newark, OH; Huntsville Botanical Garden, Huntsville, AL) from March - October 2023. The data are observations of phenology (i.e., stage of phenology or 'phenophase') recorded by volunteers on a twice-weekly basis using the Chicago Botanic Garden smartphone app 'Budburst.'  Data were originally posted on the Budburst website ([https://budburst.org/)](https://budburst.org/\)) as they were uploaded by each volunteer (user). The first author was able to access and download these publicly-available data as .csv files into Excel. The first author cleaned the data (removing erroneous/missing data rows). The main data file (PHENOLOGY_MASTER_CSV_NO_NONE_20Jul23.xlsx) contains 16 columns (metadata below). Each row of data corresponds with a single observation (1 plant per garden per observation day).  ### Files and variables #### File: PHENOLOGY\_MASTER\_CSV\_NO\_NONE\_20Jul23.xlsx **Description:**  Columns: Garden: Garden location for the observation. 'CBG' = Chicago Botanic Garden. 'Dawes' = Dawes Arboretum. 'Holden' = Holden Arboretum. 'Huntsville' = Huntsville Botanical Garden. 'Mobot' = Missouri Botanical Garden. ##### Variables 1. Garden: Garden location for the observation. 'CBG' = Chicago Botanic Garden. 'Dawes' = Dawes Arboretum. 'Holden' = Holden Arboretum. 'Huntsville' = Huntsville Botanical Garden. 'Mobot' = Missouri Botanical Garden. 2. submitted_by: observer  3. genus: Genus name of species 4. species: specific epithet of species 5. Scientific_Name: full latin binomial 6. Plant_ID: study id for each plant in the study (198 individual plants, each with a unique ID) 7. observation: date of observation (year-month-day) 8. Day Length: length of daylight per observation day (hr:min:sec) 9. High: high temperature for the day (Farenheit)  10. Low: low temperature for the day (Farenheit) 11. Avg_temp: average temperature for the day (Farenheit) 12. GDD: growing degree days 13. Cumulative GDD: Cumulative growing degree days since start of year (summed to date) 14. phenophase_plant_structure: plant structure with which the following column entry (phenophase_title) corresponds (three categories: Flower, Fruit, Leaves) phenophase_title: the phenophase the plant part (Flower, Fruit, Leaves) was in at the time of the observation. Sixteen distinct phenophases. Five correspond with leaves; 7 correspond with flowers; and four correspond with fruiting (see .xlsx file tab 'Phenophases per plant part' for breakdown of phenophases). notes: user (observer) notes corresponding to the observation. ## Code/software Microsoft Excel can be used to view the file.