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@InProceedings{AguilosSBHWCTB:2018:DoSeDr,
               author = "Aguilos, Maricar and Stahl, Clement and Burban, Benoit and 
                         Herault, Bruno and Wagner, Fabien Hubert and Courtois, Elodie and 
                         Takagi, Kentaro and Bonal, Damien",
          affiliation = "{UMR Ecologie des Forets de Guyane} and {} and {} and {} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Does seasonal drought influence ecosystem transpiration and water 
                         use efficiency in a tropical rainforest?",
                 year = "2018",
         organization = "Conference on Agricultural and Forest Meteorology, 33.",
             abstract = "Warmer and drier climates over eastern Amazonia have been 
                         predicted during the next several decades. These were expected to 
                         significantly affect the ecosystem structure and composition as 
                         well as water and carbon cycles. However, available literatures on 
                         the long-term response of the coupled water and carbon cycles to 
                         these disturbances are limited. Here, we evaluated the ecosystem 
                         water use efficiency (WUE = gross primary productivity 
                         (GPP)/evapotranspiration (ET)) to capture significant changes 
                         across the 11-year (2004 2014) period and determine their key 
                         climatic drivers. We also determined drought effect on ET, GPP and 
                         WUE. Interannual variations in WUE varied from 2.47 g C kg 
                         H2O\‒1 to 2.86 g C kg H2O\‒1 (mean = 2.64 g C kg 
                         H2O\‒1) across the years. Key climatic drivers of WUE were 
                         global radiation (Rg) as the best climate predictor followed by 
                         relative extractable water (REW) and soil temperature (Ts) (R2 = 
                         0.40; P < 0.01). At a daily timescale, linear regression analysis 
                         between Rg-normalized ET and GPP with a soil water stress index 
                         showed that when soil water stress level is strong, normalized ET 
                         and GPP were reduced. This was true among all years for ET (R2 = 
                         0.10 ~ R2 = 0.48; P < 0.05 ~ P < 0.01) and mostly in water 
                         stressed years (2005, 2008, 2009, 2012 and 2014) for GPP (R2 = 
                         0.17 ~ R2 = 0.31; P < 0.01 ~ P < 0.001). Surprisingly, 
                         Rg-normalized WUE have slightly increased with the severity soil 
                         water stress condition (except in 2005). These relationships were 
                         significant in all years (R2 = 0.04 ~ R2 = 0.24; P < 0.05 ~ P < 
                         0.001) except in 2008, 2011 and 2014. This unexpected result for 
                         WUE suggests that severe water depletion on this tropical 
                         ecosystem is not limited enough to cause considerable impact to 
                         water use efficiency, not at least within this decadal 
                         observational period in our study.",
  conference-location = "Boise, ID",
      conference-year = "14-17 may",
             language = "en",
        urlaccessdate = "24 nov. 2020"
}


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