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Título:
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Quarantining the Sahara desert: growth and water-use efficiency of Aleppo pine in the Algerian Green Barrier
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Autor/a:
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Choury, Zineb; Shestakova, Tatiana A.; Himrane, Hocine; Touchan, Ramzi; Kherchouche, Dalila; Camarero Martínez, Jesús Julio; Voltas Velasco, Jordi
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Notas:
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The Algerian Green Barrier, mainly composed of native and artificial Aleppo pine forests, spreads along the pre-Saharan steppes and is threatened by anthropogenic and natural disturbances, including climate change. We hypothesized that the ecophysiological functioning of this conifer has been substantially modified in reaction to recent warming and drought much beyond the expected effect of CO2 fertilization. Our aim was to characterize the long-term performance (1925-2013) of native Aleppo pines thriving at their southernmost distribution. We used tree-ring width (TRW) and carbon isotope discrimination (Δ¹³C) to characterize basal area increment (BAI) and intrinsic water-use efficiency (WUEi) at three sites. BAI remained stable or slightly increased over time, with mean values ranging between 4.0 and 6.3 cm² year⁻¹. Conversely, site-Δ¹³C decreased from −0.022 to −0.014 year⁻¹ along time, which translated into WUEi increases of ca. 39%. This strong physiological reaction indicated that pines were responding simultaneously to rising CO2 and drier conditions, inducing a progressively tighter stomatal control of water losses. However, WUEi increments were essentially unrelated to BAI and did not affect carbon reserves, which suggests a high resilience to climate change. This finding could be due to shifts in growing season towards earlier months in winter-spring, as suggested by temporal changes in climate factors underlying Δ¹³C and TRW. Our study highlights the substantial plasticity of Aleppo pine, but this species is unlikely to follow a similar pace of ecophysiological adjustments according to unprecedented low Δ¹³C records and lack of WUEi stimulation observed from 2000 onwards. Quarantining the Sahara desert: growth and water-use efficiency of Aleppo pine in the Algerian Green Barrier. Available from: https://www.researchgate.net/publication/310598634_Quarantining_the_Sahara_desert_growth_and_water-use_efficiency_of_Aleppo_pine_in_the_Algerian_Green_Barrier [accessed Nov 23 2017].
We acknowledge the support of the International Atomic Energy Agency (Project ALG5028) to H. Himrane and of the Spanish project FUTURPIN (AGL2015–68274–C3–3–R) to J. Voltas. We also acknowledge funding provided by the US National Science Foundation, Earth System History (Award No. 0317288) and Paleo Perspectives on Climate Change (Award No. 1103314). An earlier version of this work was presented by Z. Choury to obtain a MSc degree in the Erasmus Mundus Programme MEDfOR. T.A. Shestakova is supported by ERANET-Mundus (European Commission). We remain indebted to P. Sopeña and M.J. Pau for technical assistance. |
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Materia(s):
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-Carbon isotope discrimination
-Dendroecology
-Forest growth
-Water-use efficiency |
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Derechos:
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(c) Springer Verlag, 2016
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Tipo de documento:
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Artículo
Artículo - Versión aceptada |
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Editor:
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Springer Verlag
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Compartir:
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