Holden Arboretum, Kirtland, OH, USA.
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA.
Glob Chang Biol. 2021 Sep;27(17):4110-4124. doi: 10.1111/gcb.15685. Epub 2021 Jun 20.
Although there is abundant evidence that plant phenology is shifting with climatic warming, the magnitude and direction of these shifts can depend on the environmental context, plant species, and even the specific phenophase of study. These disparities have resulted in difficulties predicting future phenological shifts, detecting phenological mismatches and identifying other ecological consequences. Experimental warming studies are uniquely poised to help us understand how climate warming will impact plant phenology, and meta-analyses allow us to expose broader trends from individual studies. Here, we review 70 studies comprised 1226 observations of plant phenology under experimental warming. We find that plants are advancing their early-season phenophases (bud break, leaf-out, and flowering) in response to warming while marginally delaying their late-season phenophases (leaf coloration, leaf fall, and senescence). We find consistency in the magnitude of phenological shifts across latitude, elevation, and habitat types, whereas the effect of warming on nonnative annual plants is two times larger than the effect of warming on native perennial plants. Encouragingly for researchers, plant phenological responses were generally consistent across a variety of experimental warming methods. However, we found numerous gaps in the experimental warming literature, limiting our ability to predict the effects of warming on phenological shifts. In particular, studies outside of temperate ecosystems in the Northern Hemisphere, or those that focused on late-season phenophases, annual plants, nonnative plants, or woody plants and grasses, were underrepresented in our data set. Future experimental warming studies could further refine our understanding of phenological responses to warming by setting up experiments outside of traditionally studied biogeographic zones and measuring multiple plant phenophases (especially late-season phenophases) across species of varying origin, growth form, and life cycle.
尽管有大量证据表明，植物物候随着气候变暖而发生变化，但这些变化的幅度和方向可能取决于环境背景、植物物种，甚至具体的物候阶段。这些差异导致了预测未来物候变化、检测物候不匹配和识别其他生态后果的困难。实验性变暖研究具有独特的优势，可以帮助我们了解气候变暖将如何影响植物物候，而荟萃分析可以使我们从个别研究中揭示更广泛的趋势。在这里，我们回顾了 70 项研究，其中包括 1226 个植物物候实验性变暖观测结果。我们发现，植物通过变暖提前了早期的物候阶段（萌芽、展叶和开花），而略微推迟了晚期的物候阶段（叶片变色、落叶和衰老）。我们发现，在纬度、海拔和生境类型上，物候变化的幅度具有一致性，而变暖对非本地一年生植物的影响是对本地多年生植物影响的两倍。令研究人员感到鼓舞的是，植物物候反应在各种实验性变暖方法中通常是一致的。然而，我们发现实验性变暖文献中存在许多空白，限制了我们预测变暖对物候变化影响的能力。特别是，在北半球温带生态系统之外或专注于晚期物候阶段、一年生植物、非本地植物或木本植物和草类的研究，在我们的数据集中代表性不足。未来的实验性变暖研究可以通过在传统研究的生物地理区域之外设置实验，并在不同起源、生长形式和生命周期的物种中测量多个物候阶段（特别是晚期物候阶段），进一步深化我们对植物对变暖的物候反应的理解。
