Pushing precipitation to the extremes in distributed experiments: recommendations for simulating wet and dry years

作者：Alan K. Knapp, Meghan L. Avolio, Claus Beier, Charles J. W. Carroll, Scott L. Collins, Jeffrey S. Dukes, Lauchlan H. Fraser, Robert J. Griffin‐Nolan, David L. Hoover, Anke Jentsch, Michael E. Loik, Richard P. Phillips, Alison K. Post, Osvaldo E. Sala, Ingrid J. Slette, Laura Yahdjian, Melinda D. Smith · 发表于：Global Change Biology · 年份：2016 · DOI：10.1111/gcb.13504 · 被引用次数：193 · 研究领域：Hydrology and Watershed Management Studies、Peatlands and Wetlands Ecology、Climate variability and models

Intensification of the global hydrological cycle, ranging from larger individual precipitation events to more extreme multiyear droughts, has the potential to cause widespread alterations in ecosystem structure and function. With evidence that the incidence of extreme precipitation years (defined statistically from historical precipitation records) is increasing, there is a clear need to identify ecosystems that are most vulnerable to these changes and understand why some ecosystems are more sensitive to extremes than others. To date, opportunistic studies of naturally occurring extreme precipitation years, combined with results from a relatively small number of experiments, have provided limited mechanistic understanding of differences in ecosystem sensitivity, suggesting that new approaches are needed. Coordinated distributed experiments (CDEs) arrayed across multiple ecosystem types and focused on water can enhance our understanding of differential ecosystem sensitivity to precipitation extremes, but there are many design challenges to overcome (e.g., cost, comparability, standardization). Here, we evaluate contemporary experimental approaches for manipulating precipitation under field conditions to inform the design of 'Drought-Net', a relatively low-cost CDE that simulates extreme precipitation years. A common method for imposing both dry and wet years is to alter each ambient precipitation event. We endorse this approach for imposing extreme precipitation years because ...