Intra‐annual precipitation effects on annual grassland productivity and phenology are moderated by community responses
Intra‐annual precipitation effects on annual grassland productivity and phenology are moderated by community responses
复制标题
年内降水量对草地生产力和物候的影响受到群落反应的调节
DOI：
10.1111/1365-2745.13792
复制
发表时间：
2021
影响因子：
5.5
通讯作者：
L. Hallett
中科院分区：
文献类型：
--
作者：
E. Shaw;Caitlin T. White;W. Silver;K. Suding;L. Hallett
在生态系统内，年内降水模式——降雨的变率和时间——可能比年总降水量更能驱动净初级生产力。特别是降水的数量和时间直接影响植物生产的数量和时间，但也通过植物群落组成的变化间接影响生产力。群落响应模式可能缓冲或放大生产力对降水的响应，因为不同的物种对不同的条件做出响应。在半干旱的加利福尼亚草原上，我们通过实验测试了植物群落对年内降水的响应，我们在3年的时间里利用降雨掩蔽来控制干旱的数量和时间（早季干旱、晚季干旱、连续干旱和环境降水），并评估了植物对年净初级生产力（ANPP）、峰值生产和衰老的物候时间以及群落组成的响应。总体而言，早季和持续干旱处理的生产力最低，而晚季和持续干旱处理的衰老较早。群落功能多样的样地群落组成发生变化，对降水处理有显著的ANPP响应。相比之下，以单一资源获取性禾草为主的群落组成不随时间变化，且对降水处理没有ANPP响应。然而，不同群落的生产时间也不同，功能多样化的群落保持绿色的时间更长（特别是在早季干旱处理下），而由一种草主导的群落衰老得更早（特别是在晚季干旱处理下）。合成。我们的研究表明，干旱模式可能通过植物群落组成和物候的响应间接驱动ANPP。这表明，在未来气候变化下，物种组成和植被物候的结合可能共同改变生态系统对降水季节性的敏感性。研究表明，功能多样性和优势稳定性机制同时发挥作用，这表明需要同时了解群落结构的背景和变化，以预测ANPP对年际降水的响应。
Within ecosystems, intra‐annual precipitation patterns—the variability and timing of rainfall—may be a stronger driver of net primary productivity than total annual precipitation. In particular, the amount and timing of precipitation directly affects the amount and timing of plant production, but also indirectly affects productivity via changes to plant community composition. Community response patterns may either buffer or amplify productivity responses to precipitation, as different species respond to different conditions. In a semi‐arid California grassland, we experimentally tested how plant communities respond to intra‐annual precipitation using rainout shelters in which we manipulated drought amount and timing (early season drought, late season drought, continuous drought and ambient precipitation) over 3 years and assessed plant responses: annual net primary productivity (ANPP), phenological timing of peak production and senescence, and community composition. Overall, early season and consistent drought treatments had lowest productivity, while late season and consistent drought treatments senesced earlier. Plots with functionally diverse communities shifted community composition and had a significant ANPP response to precipitation treatments. In contrast, communities dominated by a single resource‐acquisitive grass species did not change in community composition over time and had no ANPP response to precipitation treatments. The timing of production also differed by community, however, where functionally diverse communities remained green longer (particularly under the early season drought treatment) compared to communities dominated by one grass species, which senesced earlier (particularly under the late season drought treatment). Synthesis. Our study demonstrates that drought patterns may indirectly drive ANPP via plant community responses in composition and phenology. This suggests that the combination of species composition and vegetation phenology could jointly alter ecosystem‐level sensitivity to precipitation seasonality under future climate change. We show that both functional diversity and dominant stability mechanisms are in operation simultaneously, highlighting the need to understand both the context and variation in community structure to predict ANPP responses to intra‐annual precipitation.
影响因子：
11.6
作者：
Gherardi, Laureano A.;Sala, Osvaldo E.
通讯作者：
Sala, Osvaldo E.