@article {KNZ001739,
	title = {Productivity of North American grasslands is increased under future climate scenarios despite rising aridity},
	journal = {Nature Climate Change},
	volume = {6},
	year = {2016},
	pages = {710-714},
	abstract = {<p>Grassland productivity is regulated by both temperature and the amount and timing of precipitation1, 2. Future climate change is therefore expected to influence grassland phenology and growth, with consequences for ecosystems and economies. However, the interacting effects of major shifts in temperature and precipitation on grasslands remain poorly understood and existing modelling approaches, although typically complex, do not extrapolate or generalize well and tend to disagree under future scenarios3, 4. Here we explore the potential responses of North American grasslands to climate change using a new, data-informed vegetation\&ndash;hydrological model, a network of high-frequency ground observations across a wide range of grassland ecosystems and CMIP5 climate projections. Our results suggest widespread and consistent increases in vegetation fractional cover for the current range of grassland ecosystems throughout most of North America, despite the increase in aridity projected across most of our study area. Our analysis indicates a likely future shift of vegetation growth towards both earlier spring emergence and delayed autumn senescence, which would compensate for drought-induced reductions in summer fractional cover and productivity. However, because our model does not include the effects of rising atmospheric CO2 on photosynthesis and water use efficiency5, 6, climate change impacts on grassland productivity may be even larger than our results suggest. Increases in the productivity of North American grasslands over this coming century have implications for agriculture, carbon cycling and vegetation feedbacks to the atmosphere.</p>},
	keywords = {LTER-KNZ},
	issn = {1758-678X},
	doi = {10.1038/nclimate2942},
	url = {https://www.nature.com/articles/nclimate2942},
	author = {Hufkens, K. and Keenan, T.F. and Flanagan, L.B. and Scott, R.L. and Bernacchi, C.J. and Joo, E. and N. Brunsell and Verfaillie, J. and Richardson, A.D.}
}
@article {KNZ001729,
	title = {Warm spring reduced carbon cycle impact of the 2012 US summer drought},
	journal = {Proceedings of the National Academy of Sciences},
	year = {2016},
	pages = {201519620},
	abstract = {<p>The global terrestrial carbon sink offsets one-third of the world\&rsquo;s fossil fuel emissions, but the strength of this sink is highly sensitive to large-scale extreme events. In 2012, the contiguous United States experienced exceptionally warm temperatures and the most severe drought since the Dust Bowl era of the 1930s, resulting in substantial economic damage. It is crucial to understand the dynamics of such events because warmer temperatures and a higher prevalence of drought are projected in a changing climate. Here, we combine an extensive network of direct ecosystem flux measurements with satellite remote sensing and atmospheric inverse modeling to quantify the impact of the warmer spring and summer drought on biosphere-atmosphere carbon and water exchange in 2012. We consistently find that earlier vegetation activity increased spring carbon uptake and compensated for the reduced uptake during the summer drought, which mitigated the impact on net annual carbon uptake. The early phenological development in the Eastern Temperate Forests played a major role for the continental-scale carbon balance in 2012. The warm spring also depleted soil water resources earlier, and thus exacerbated water limitations during summer. Our results show that the detrimental effects of severe summer drought on ecosystem carbon storage can be mitigated by warming-induced increases in spring carbon uptake. However, the results also suggest that the positive carbon cycle effect of warm spring enhances water limitations and can increase summer heating through biosphere\&ndash;atmosphere feedbacks.</p>},
	keywords = {LTER-KNZ, biosphere{\textendash}atmosphere feedbacks, carbon uptake, ecosystem fluxes, Eddy covariance, seasonal climate anomalies},
	issn = {0027-8424},
	doi = {10.1073/pnas.1519620113},
	url = {https://www.pnas.org/content/113/21/5880},
	author = {Wolf, S. and Keenan, T.F. and Fisher, J.B. and Baldocchi, D.D. and Desai, A.R. and Richardson, A.D. and Scott, R.L. and Law, B.E. and Litvak, M.E. and N. Brunsell and Peters, W. and van der Laan-Luijkx, I.T.}
}
