Section of Botany, Carnegie Museum of Natural History, Pittsburgh, PA, 15213, USA.
Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, 37996, USA.
Ecol Lett. 2019 Apr;22(4):616-623. doi: 10.1111/ele.13224. Epub 2019 Feb 3.
Interacting species can respond differently to climate change, causing unexpected consequences. Many understorey wildflowers in deciduous forests leaf out and flower in the spring when light availability is the highest before overstorey canopy closure. Therefore, different phenological responses by understorey and overstorey species to increased spring temperature could have significant ecological implications. Pairing contemporary data with historical observations initiated by Henry David Thoreau (1850s), we found that overstorey tree leaf out is more responsive to increased spring temperature than understorey wildflower phenology, resulting in shorter periods of high light in the understorey before wildflowers are shaded by tree canopies. Because of this overstorey-understorey mismatch, we estimate that wildflower spring carbon budgets in the northeastern United States were 12-26% larger during Thoreau's era and project a 10-48% reduction during this century. This underappreciated phenomenon may have already reduced wildflower fitness and could lead to future population declines in these ecologically important species.
相互作用的物种对气候变化的反应可能不同，从而导致意想不到的后果。落叶林的许多下层野生花卉在春季光可用性最高的时候（即在树冠闭合之前）展叶和开花。因此，下层和上层物种对春季温度升高的不同物候反应可能具有重要的生态意义。我们将当代数据与亨利·大卫·梭罗（19 世纪 50 年代）发起的历史观测配对，发现上层树木的展叶对春季温度升高的反应比下层野生花卉的物候更敏感，导致在野生花卉被树冠遮蔽之前，下层的高光时间更短。由于这种上层和下层的不匹配，我们估计在梭罗时代，美国东北部的野生花卉春季碳预算增加了 12-26%，并预计本世纪将减少 10-48%。这种被低估的现象可能已经降低了野生花卉的适应性，并可能导致这些在生态上重要的物种未来的种群数量下降。
