TY - DATA T1 - Water-use efficiency (WUE), i.e. the ratio of gross primary productivity (GPP) and ecosystem evapotranspiration (ET), in spring 2011 compared to 2010 PY - 2013/07/03 AU - Sebastian Wolf AU - Lutz Merbold AU - Dennis Imer AU - Jacqueline Stieger AU - Rebecca Hiller AU - Sebastian Zielis AU - Matthias Häni AU - Christof Ammann AU - Werner Eugster AU - Nina Buchmann UR - https://iop.figshare.com/articles/figure/_Water_use_efficiency_WUE_i_e_the_ratio_of_gross_primary_productivity_GPP_and_ecosystem_evapotranspi/1011686 DO - 10.6084/m9.figshare.1011686.v1 L4 - https://ndownloader.figshare.com/files/1479511 KW - forest sites Laegeren KW - European summer heat wave KW - spring drought KW - ecosystem KW - water vapour fluxes KW - spring 2011 KW - spring phenological development KW - mf KW - et KW - gra KW - enf KW - Swiss FluxNet data KW - wue KW - lowland grassland sites KW - gpp KW - IGBP KW - evergreen needleleaf forest KW - productivity KW - Environmental Science N2 - Figure 7. Water-use efficiency (WUE), i.e. the ratio of gross primary productivity (GPP) and ecosystem evapotranspiration (ET), in spring 2011 compared to 2010. Significant differences in WUE (slopes) were detected at the forest sites Laegeren (d) and Davos (e), both p < 0.001. Abbreviations in titles indicate the IGBP land-use class with grasslands (GRA), mixed forest (MF) and evergreen needleleaf forest (ENF). Abstract Since the European summer heat wave of 2003, considerable attention has been paid to the impacts of exceptional weather events on terrestrial ecosystems. While our understanding of the effects of summer drought on ecosystem carbon and water vapour fluxes has recently advanced, the effects of spring drought remain unclear. In Switzerland, spring 2011 (March–May) was the warmest and among the driest since the beginning of meteorological measurements. This study synthesizes Swiss FluxNet data from three grassland and two forest ecosystems to investigate the effects of this spring drought. Across all sites, spring phenological development was 11 days earlier in 2011 compared to the mean of 2000–2011. Soil moisture related reductions of gross primary productivity (GPP) were found at the lowland grassland sites, where productivity did not recover following grass cuts. In contrast, spring GPP was enhanced at the montane grassland and both forests (mixed deciduous and evergreen). Evapotranspiration (ET) was reduced in forests, which also substantially increased their water-use efficiency (WUE) during spring drought, but not in grasslands. These contrasting responses to spring drought of grasslands compared to forests reflect different adaptive strategies between vegetation types, highly relevant to biosphere–atmosphere feedbacks in the climate system. ER -