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.

除了局部空间尺度和较短时间段（数周至 30个月）。然而，花卉对气候和小气候的影响尚不清楚。我们研究了花是否会影响亚高山草甸地表反射的光和土壤小气候。我们对常见的向日葵品种Helianthella quinquenervis进行了为期 3 年（2015、2017和 2019 年）的去花实验。去花处理模拟向日葵时草地的外观在气候变化下开花更早，并因霜冻而失去花朵（其他植物结构不会被霜冻损坏）。我们测试了以下假设：减少黄色花朵的覆盖会导致更绿的地表、更低的反射率、更温暖和更干燥的土壤以及增加植物水分胁迫。摘花地更绿，反射更少的光，在最温暖的白天显示出高达 1.2 °C 的土壤温度，并且含有约 与对照相比，土壤水分减少 1%。然而，在 3 年中，只有 2 年土壤温度较高，此时花卉丰度较高。向日葵去除地块和对照地块之间的用水效率没有差异。我们的研究为先前未记录的花卉对土壤小气候的影响提供了证据，这种影响可能是由气候变化和开花物候调节的。许多人为环境变化会改变景观反照率，所有这些都可以通过花卉来调节：气候变化、植物入侵和农业。这项研究强调了进一步考虑花卉对地表反照率的影响如何可以提高我们对植被对小气候影响的理解。