Organisms across the globe are experiencing shifts in phenological events as a result of ongoing climate change. Recently, a variety of novel methods have been applied in order to fill gaps in the phenological data set, in which records often have a patchy temporal, spatial, and/or taxonomic resolution. Here, I tested whether changes in flowering phenology could be detected through the months of flowering stated in 11 guides to the Swedish flora published over a period of 220 yr (1798–2018), focussing on 241 plant species (approximately 8% of the Swedish flora), and accounting for the large increase in herbarium records that have occurred over the same period. Despite the coarse, monthly scale of flowering times reported, historical floras and wildflower guides may hold potential to fill temporal and taxonomic gaps in the plant phenological data set. However, factors other than climate may also influence any apparent phenological shifts over time. Here, flowering was found to start earlier (0.49 d/decade), end later (0.71 d/decade), and carry on longer (1.19 d/decade), with flowering length also associated with increases in the regional temperature anomaly during the 20th century (0.11 months/°C). First flowering occurring earlier in 71% of species (14% showing a significant negative trend), 68% of species ceased flowering later (20%), and 80% flowered for longer (29%). Detected phenological shifts also appeared to be related to species’ flowering seasonality. Later-flowering species were found to flower later and for longer, while increasing temperatures appeared to drive stronger responses both in flowering onset in early-flowering species and in flowering cessation in later-flowering species. Although potential issues exist regarding the largely unknown ways by which authors have determined flowering times and the coarseness of the data, historical floras may be a useful resource in phenological and climate change research, with the potential to both identify and compare the broad climatic responses of a region’s entire flora over long time periods, as well as filling gaps in an otherwise patchy data set.

中文翻译：

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历史植物群反映了气候变暖导致开花物候的广泛变化

由于持续的气候变化，全球的生物体正在经历物候事件的变化。最近，已经应用了各种新方法来填补物候数据集中的空白，其中记录通常具有不完整的时间、空间和/或分类分辨率。在这里，我测试了在 220 年（1798-2018 年）期间出版的 11 份瑞典植物群指南中所述的开花月份是否可以检测到开花物候的变化，重点关注 241 种植物物种（约占瑞典植物种类的 8%）。植物群），并解释了同期发生的植物标本馆记录的大量增加。尽管报告了粗略的每月开花时间尺度，历史植物群和野花指南可能有潜力填补植物物候数据集中的时间和分类空白。然而，气候以外的因素也可能影响任何明显的物候随时间的变化。在这里，发现开花开始较早（0.49 d/decade），结束较晚（0.71 d/decade），持续时间较长（1.19 d/decade），开花长度也与20世纪区域温度异常的增加有关世纪（0.11 个月/°C）。71% 的物种首次开花较早（14% 显示出显着的负趋势），68% 的物种开花较晚（20%），80% 的物种开花时间更长（29%）。检测到的物候变化似乎也与物种的开花季节性有关。发现较晚开花的物种开花较晚且持续时间较长，而升高的温度似乎对早花物种的开花开始和晚花物种的开花停止产生更强的反应。尽管作者确定开花时间和数据粗糙程度的未知方式存在潜在问题，但历史植物群可能是物候和气候变化研究的有用资源，具有识别和比较广泛气候响应的潜力一个地区在很长一段时间内的整个植物群，以及填补原本不完整的数据集中的空白。