Soil and stand structure explain shrub mortality patterns following global change type-drought and extreme precipitation.

摘要: The probability of extreme weather events is increasing, with the potential for widespread impacts to plants, plant communities, and ecosystems. Reports drought-related tree mortality are becoming more frequent, there increasing evidence that drought accompanied by high temperatures especially detrimental. Simultaneously, large precipitation have become frequent over past century. Water-limited ecosystems may be vulnerable these than other ecosystems, when pushed outside their historical range variability. However, shrubs-an important component dryland vegetation-remains understudied relative mortality. In 2014, a landscape-scale die-off shrub, big sagebrush (Artemisia tridentata Nutt.), was reported in southwest Wyoming, following hot dry conditions 2012 extremely September 2013. Here we examine how severe drought, precipitation, soil texture salinity, shrub-stand characteristics contributed this event. At 98 plots within around die-off, quantified mortality, characterized simulated soil-water from 1916 2016 using an ecosystem water-balance model. We found alone did not explain patterns result (historically unprecedented) during drought. Instead, chronically experienced greatest global change-type (hot) 2012. Furthermore, greater locations run-on low run-off where saturated were 2013, suggesting also played role locations. stem density negatively impacted sagebrush. been affected both saturation, however, lowest, already less favorable Paradoxically, vulnerability (drought saturation) associated finer-textured soils, our results highlight importance soils determining local variation plants events.