@article {KNZ001730,
	title = {Few multiyear precipitation{\textendash}reduction experiments find a shift in the productivity{\textendash}precipitation relationship},
	journal = {Global Change Biology},
	volume = {22},
	year = {2016},
	pages = {2570-2581},
	abstract = {<p>Well-defined productivity\&ndash;precipitation relationships of ecosystems are needed as benchmarks for the validation of land models used for future projections. The productivity\&ndash;precipitation relationship may be studied in two ways: the spatial approach relates differences in productivity to those in precipitation among sites along a precipitation gradient (the spatial fit, with a steeper slope); the temporal approach relates interannual productivity changes to variation in precipitation within sites (the temporal fits, with flatter slopes). Precipitation\&ndash;reduction experiments in natural ecosystems represent a complement to the fits, because they can reduce precipitation below the natural range and are thus well suited to study potential effects of climate drying. Here, we analyse the effects of dry treatments in eleven multiyear precipitation\&ndash;manipulation experiments, focusing on changes in the temporal fit. We expected that structural changes in the dry treatments would occur in some experiments, thereby reducing the intercept of the temporal fit and displacing the productivity\&ndash;precipitation relationship downward the spatial fit. The majority of experiments (72\%) showed that dry treatments did not alter the temporal fit. This implies that current temporal fits are to be preferred over the spatial fit to benchmark land-model projections of productivity under future climate within the precipitation ranges covered by the experiments. Moreover, in two experiments, the intercept of the temporal fit unexpectedly increased due to mechanisms that reduced either water loss or nutrient loss. The expected decrease of the intercept was observed in only one experiment, and only when distinguishing between the late and the early phases of the experiment. This implies that we currently do not know at which precipitation\&ndash;reduction level or at which experimental duration structural changes will start to alter ecosystem productivity. Our study highlights the need for experiments with multiple, including more extreme, dry treatments, to identify the precipitation boundaries within which the current temporal fits remain valid.</p>},
	keywords = {LTER-KNZ},
	doi = {10.1111/gcb.13269},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13269},
	author = {Estiarte, M. and Vicca, S. and Pe{\~n}uelas, J. and Michael Bahn and Beier, C. and Emmett, B.A. and Fay, P.A. and Hanson, P.J. and R. Hasibeder and Kigel, J. and Kr{\"o}el-Dulay, G. and Larsen, K.S. and Lellei-Kov{\'a}cs, E. and Limousin, J-M. and Ogaya, R. and Ourcival, J-M. and Reinsch, S. and Sala, O.E. and Schmidt, I.K. and Sternberg, M. and Tielb{\"o}rger, K. and Tietema, A. and Janssens, I.A.}
}
@article {KNZ001798,
	title = {Quantifying global soil carbon losses in response to warming},
	journal = {Nature},
	volume = {540},
	year = {2016},
	pages = {104 - 108},
	abstract = {<p>The majority of the Earth\&rsquo;s terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming, Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30\&thinsp;\&plusmn;\&thinsp;30 petagrams of carbon to 203\&thinsp;\&plusmn;\&thinsp;161 petagrams of carbon under one degree of warming, depending on the rate at which the effects of warming are realized. Under the conservative assumption that the response of soil carbon to warming occurs within a year, a business-as-usual climate scenario would drive the loss of 55\&thinsp;\&plusmn;\&thinsp;50 petagrams of carbon from the upper soil horizons by 2050. This value is around 12\&ndash;17 per cent of the expected anthropogenic emissions over this period. Despite the considerable uncertainty in our estimates, the direction of the global soil carbon response is consistent across all scenarios. This provides strong empirical support for the idea that rising temperatures will stimulate the net loss of soil carbon to the atmosphere, driving a positive land carbon\&ndash;climate feedback that could accelerate climate change.</p>},
	keywords = {LTER-KNZ, Biogeochemistry, carbon cycle},
	doi = {10.1038/nature20150},
	url = {https://www.nature.com/articles/nature20150},
	author = {Crowther, T. W. and Todd-Brown, K. E. O. and Rowe, C. W. and Wieder, W. R. and Carey, J. C. and Machmuller, M. B. and Snoek, B. L. and Fang, S. and Zhou, G. and Allison, S. D. and John M. Blair and Bridgham, S. D. and Burton, A. J. and Carrillo, Y. and Reich, P. B. and Clark, J. S. and Classen, A. T. and Dijkstra, F. A. and Elberling, B. and Emmett, B. A. and Estiarte, M. and Frey, S. D. and Guo, J. and Harte, J. and Jiang, L. and Johnson, B. R. and Kr{\"o}el-Dulay, G. and Larsen, K. S. and Laudon, H. and Lavallee, J. M. and Luo, Y. and Lupascu, M. and Ma, L. N. and Marhan, S. and Michelsen, A. and Mohan, J. and Niu, S. and Pendall, E. and {\~n}uelas, J. and Pfeifer-Meister, L. and Poll, C. and Reinsch, S. and Reynolds, L. L. and Schmidt, I. K. and Sistla, S. and Sokol, N. W. and Templer, P. H. and Treseder, K. K. and Welker, J. M. and Bradford, M. A.}
}
