ENSO effects on the transpiration of eastern Amazon trees.

Autor: Brum M; Department of Plant Biology, Institute of Biology, CP 6109, State University of Campinas - UNICAMP, Campinas, São Paulo 13083-970, Brazil maurobrumjr@gmail.com., Gutiérrez López J; Earth Systems Research Center, University of New Hampshire, Durham, NH 03824, USA., Asbjornsen H; Earth Systems Research Center, University of New Hampshire, Durham, NH 03824, USA heidi.asbjornsen@unh.edu., Licata J; Instituto Nacional de Tecnología Agropecuaria, Estación Experimental Concordia, Concordia, Entre Ríos, Argentina., Pypker T; Department of Natural Resource Sciences, Thompson Rivers University, Kamloops, British Columbia, Canada V2C0C8., Sanchez G; AGROPALMA Company, PA-150 Highway, No Number, Km 74, Tailândia, Pará 68695-000, Brazil., Oiveira RS; Department of Plant Biology, Institute of Biology, CP 6109, State University of Campinas - UNICAMP, Campinas, São Paulo 13083-970, Brazil rafaelsoliv@gmail.com.
Jazyk: angličtina
Zdroj: Philosophical transactions of the Royal Society of London. Series B, Biological sciences [Philos Trans R Soc Lond B Biol Sci] 2018 Oct 08; Vol. 373 (1760). Date of Electronic Publication: 2018 Oct 08.
DOI: 10.1098/rstb.2018.0085
Abstrakt: Tree transpiration is important in the recycling of precipitation in the Amazon and might be negatively affected by El Niño-Southern Oscillation (ENSO)-induced droughts. To investigate the relative importance of soil moisture deficits versus increasing atmospheric demand (VPD) and determine if these drivers exert different controls over tree transpiration during the wet season versus the dry season (DS), we conducted sap flow measurements in a primary lowland tropical forest in eastern Amazon during the most extreme ENSO-induced drought (2015/2016) recorded in the Amazon. We also assessed whether trees occupying different canopy strata contribute equally to the overall stand transpiration ( T stand ). Canopy trees were the primary source of T stand However, subcanopy trees are still important as they transpired an amount similar to other biomes around the globe. Tree water use was higher during the DS, indicating that during extreme drought trees did not reduce transpiration in response to low soil moisture. Photosynthetically active radiation and VPD exerted an overriding effect on water use patterns relative to soil moisture during extreme drought, indicating that light and atmospheric constraints play a critical role in controlling ecosystem fluxes of water. Our study highlights the importance of canopy and subcanopy trees to the regional water balance and highlights the resilience to droughts that these trees show during an extreme ENSO event.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
(© 2018 The Author(s).)
Databáze: MEDLINE
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