Van Dyke Mary N, Kraft Nathan J B
Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, USA.
Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA.
Am J Bot. 2025 Feb;112(2):e70000. doi: 10.1002/ajb2.70000. Epub 2025 Feb 5.
Shifts in the timing of life history events, or phenology, have been recorded across many taxa and biomes in response to global change. These phenological changes are often studied in a single species context, but considering the community context is essential for anticipating the cascading effects on biotic interactions that are likely to occur. Focusing on an annual grassland plant community, we examined how experimental changes in precipitation affect flowering phenology in a community context and explore the implications of these shifts for competitive interactions and species coexistence.
We experimentally manipulated rainfall with rainout shelters and recorded detailed flowering phenology data for seven annual species including two grasses and five forbs. We assessed how their first and peak flowering days were affected by changes in rainfall and explored how flowering overlap between competing species changed.
Changes in rainfall shifted flowering phenology of some species, but sensitivity differed among neighboring species. Four of the seven species studied started and/or peaked flowering earlier in response to reduced water availability. The idiosyncratic shifts in flowering phenology have the potential to alter existing temporal dynamics that may be maintaining coexistence, such as temporal separation of resource-use among neighbors.
Our results show how species-specific phenological consequences of global change can impact community dynamics and competition between neighboring plants and warrant future research.
为响应全球变化，许多分类群和生物群落中都记录到了生活史事件时间或物候的变化。这些物候变化通常在单一物种背景下进行研究，但考虑群落背景对于预测可能发生的对生物相互作用的连锁效应至关重要。以一年生草原植物群落为研究对象，我们研究了降水的实验性变化如何在群落背景下影响开花物候，并探讨了这些变化对竞争相互作用和物种共存的影响。
我们使用遮雨棚对降雨进行实验性操控，并记录了包括两种禾本科植物和五种非禾本科植物在内的七个一年生物种的详细开花物候数据。我们评估了它们的首次开花日和盛花期如何受到降雨变化的影响，并探讨了竞争物种之间开花重叠情况的变化。
降雨变化改变了一些物种的开花物候，但相邻物种的敏感性有所不同。所研究的七个物种中有四个因水分供应减少而提前开始和/或达到盛花期。开花物候的特殊变化有可能改变可能维持共存的现有时间动态，例如相邻植物间资源利用的时间分离。
我们的研究结果表明全球变化的物种特异性物候后果如何影响群落动态以及相邻植物之间的竞争，值得未来开展相关研究。
