@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",
targetfile = "Does seasonal drought.pdf",
urlaccessdate = "03 jun. 2024"
}