02530nas a2200241   4500008004100000245008400041210006900125300001300194490000800207520176300215653001901978653002501997653003402022653001802056653002302074100002002097700002002117700001702137700002802154700002402182700001602206856006602222       2015                        eng d00aDifferential sensitivity to regional-scale drought in six central US grasslands0 aDifferential sensitivity to regionalscale drought in six central  a949 -9570 v1773 a<p>Terrestrial ecosystems often vary dramatically in their responses to drought, but the reasons for this are unclear. With climate change forecasts for more frequent and extensive drought in the future, a more complete understanding of the mechanisms that determine differential ecosystem sensitivity to drought is needed. In 2012, the Central US experienced the fourth largest drought in a century, with a regional-scale 40 % reduction in growing season precipitation affecting ecosystems ranging from desert grassland to mesic tallgrass prairie. This provided an opportunity to assess ecosystem sensitivity to a drought of common magnitude in six native grasslands. We tested the prediction that drought sensitivity is inversely related to mean annual precipitation (MAP) by quantifying reductions in aboveground net primary production (ANPP). Long-term ANPP data available for each site (mean length = 16 years) were used as a baseline for calculating reductions in ANPP, and drought sensitivity was estimated as the reduction in ANPP per millimeter reduction in precipitation. Arid grasslands were the most sensitive to drought, but drought responses and sensitivity varied by more than twofold among the six grasslands, despite all sites experiencing 40 % reductions in growing season precipitation. Although drought sensitivity generally decreased with increasing MAP as predicted, there was evidence that the identity and traits of the dominant species, as well as plant functional diversity, influenced sensitivity. A more comprehensive understanding of the mechanisms leading to differences in drought sensitivity will require multi-site manipulative experiments designed to assess both biotic and abiotic determinants of ecosystem sensitivity.</p>10aClimate change10aFunctional diversity10aLong-term ecological research10aPrecipitation10aPrimary production1 aKnapp, Alan, K.1 aCarroll, C.J.W.1 aDenton, E.M.1 aLa Pierre, Kimberly, J.1 aCollins, Scott., L.1 aSmith, M.D.  uhttps://link.springer.com/article/10.1007%2Fs00442-015-3233-6