Data from: Phenological responses to multiple environmental drivers under climate change: insights from a long-term observational study and a manipulative field experiment

• Climate change has induced pronounced shifts in the reproductive phenology of plants, yet we know little about which environmental factors contribute to interspecific variation in responses and their effects on fitness. • We integrate data from a 43-year record of first flowering for six species in subalpine Colorado meadows with a 3-year snow manipulation experiment on the perennial forb Boechera stricta (Brassicaceae) from the same site. We analyze shifts in the onset of flowering in relation to environmental drivers known to influence phenology: the timing of snowmelt, the accumulation of growing degree days, and photoperiod.• Variation in responses to climate change depended on the sequence in which species flowered, with early-flowering species reproducing faster, at a lower heat sum, and under increasingly disparate photoperiods relative to later-flowering species. Early snow removal treatments confirm that the timing of snowmelt governs observed trends in flowering phenology of B. stricta and that climate change can reduce the probability of flowering, thereby depressing fitness. • Our findings suggest that climate change is decoupling historical combinations of photoperiod and temperature and outpacing phenological changes for our focal species. Accurate predictions of biological responses to climate change require a thorough understanding of the factors driving shifts in phenology.Boechera_experiment_snowmeltThis file includes the snowmelt dates from the Boechera stricta experiment (Table S7).Boechera_experiment_phenologyThis file contains individual-level phenology data for the Boechera stricta experiment (Tables S8-S10).Boechera_experiment_flowering_successThis file contains family-level flowering success data for the Boechera stricta experiment (Tables S11a-S11c).PhotoperiodThis file contains daylength data local to the study site for every day of the study period.Observational_phenologyThis file contains data of the date of first flower, date of snowmelt, accumulated growing degree days at first flower, and daylength at first flower for the six species monitored in the observational experiment.TemperatureThis file contains minimum temperature, maximum temperature, and average temperature, and growing degree day data for every day of the study period.SnowmeltThis file contains data for the ordinal date of snowmelt for out study region from 1936-2016.Funding provided by: National Science FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000001Award Number: DEB-1553408, DEB-9408382, IBN-9814509, DEB-0238331, DEB-0922080, DEB-135410