Pushing precipitation to the extremes in distributed experiments: recommendations for simulating wet and dry years
- 1 November 2016
- journal article
- Published by Wiley in Global Change Biology
- Vol. 23 (5), 1774-1782
- https://doi.org/10.1111/gcb.13504
Abstract
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 it simultaneously alters other precipitation characteristics (i.e., event size) consistent with natural precipitation patterns. However, we do not advocate applying identical treatment levels at all sites – a common approach to standardization in CDEs. This is because precipitation variability varies >fivefold globally resulting in a wide range of ecosystem-specific thresholds for defining extreme precipitation years. For CDEs focused on precipitation extremes, treatments should be based on each site's past climatic characteristics. This approach, though not often used by ecologists, allows ecological responses to be directly compared across disparate ecosystems and climates, facilitating process-level understanding of ecosystem sensitivity to precipitation extremes.Keywords
Funding Information
- US National Science Foundation
- Drought-Net Research Coordination Network
- Extreme Drought in Grasslands (EDGE)
This publication has 63 references indexed in Scilit:
- Precipitation extremes over the continental United States in a transient, high‐resolution, ensemble climate model experimentJournal of Geophysical Research: Atmospheres, 2013
- Automated rainfall manipulation system: a reliable and inexpensive tool for ecologistsEcosphere, 2013
- Dynamics of evapotranspiration partitioning in a semi-arid forest as affected by temporal rainfall patternsAgricultural and Forest Meteorology, 2012
- Increased rainfall variability reduces biomass and forage quality of temperate grassland largely independent of mowing frequencyAgriculture, Ecosystems & Environment, 2012
- An ecological perspective on extreme climatic events: a synthetic definition and framework to guide future researchJournal of Ecology, 2011
- Climate extremes initiate ecosystem‐regulating functions while maintaining productivityJournal of Ecology, 2011
- Coordinated approaches to quantify long‐term ecosystem dynamics in response to global changeGlobal Change Biology, 2011
- Evidence for intensification of the global water cycle: Review and synthesisJournal of Hydrology, 2006
- Sensitivity of canopy transpiration to altered precipitation in an upland oak forest: evidence from a long‐term field manipulation studyGlobal Change Biology, 2005
- RESPONSES OF TUNDRA PLANTS TO EXPERIMENTAL WARMING:META-ANALYSIS OF THE INTERNATIONAL TUNDRA EXPERIMENTEcological Monographs, 1999