Título:
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Drought decreases growth and increases mortality of coexisting native and introduced tree species in a temperate floodplain forest
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Autor/a:
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Colangelo, Michele; Camarero, J. Julio; Ripullone, Francesco; Gazol, Antonio; Sánchez-Salguero, Raúl; Oliva Palau, Jonàs; Redondo, Miguel Ángel
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Notas:
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Forest dieback and mortality events induced by drought stress are widely reported.
However, few studies have jointly examined the role played by drought on growth and mortality in
tree species inhabiting floodplain forests. Here, we focused on mortality events occurring since the
early 2000s on large areas in a floodplain forest located within the Ticino regional park in Northwest
Italy, where affected native (pedunculate oak, Quercus robur L.) and introduced tree species (black
locust, Robinia pseudoacacia L.) coexist. We related growth with climate data and drought severity to
discern if these species were similarly affected by drought. Then, we: (i) evaluated the presence of
pathogens of the genus Phytophthora in recently dead oak trees since this was the most affected species
and pathogens are often associated with oak decline cases; and (ii) compared xylem vessel diameter
and tree-ring C isotope discrimination ( 13C) to highlight differences in water-use strategies between
living and dead trees in both species. The radial growth of living and dead trees started diverging
in the 1970s, although only after warm-drought periods occurred during 1990s did this divergence
become significant. Growth of trees that died responded more negatively to drought than in the
case of living trees. Moreover, trees that died formed smaller xylem vessels in the past than living
trees and also showed more negative 13C values in both tree species, indicating a higher intrinsic
water-use efficiency in living than in dead trees. The pathogen Phytophthora cinnamomi Rands was
only detected in one recently dead tree, suggesting that it is unlikely that dead oaks were predisposed
to drought damage by the pathogen. We conclude that a climate shift from wet to warm-dry summer
conditions in the early 1990s triggered forest dieback and induced mortality in both tree species.
Temperate floodplain forests are susceptible to drought-induced dieback. The drought-sensitivity of
both species could lead to successional shifts driven by a reduction of N inputs through N-fixing by
black locust and the replacement of oak by drought-tolerant species.
This research was funded by the projects “Convenzione Rotondella” (Rotondella Administration, Basilicata Region, Italy) and CGL2015-69186-C2-1-R project (Spanish Ministry of Economy). M.C. was supported by the PhD program from the course of Agricultural, Forest and Food Science at the University of Basilicata (Italy) |
Materia(s):
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-Dendroecology -Drought stress -Growth -Fungal pathogens |
Derechos:
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cc-by, (c) Colangelo et al., 2018
http://creativecommons.org/licenses/by/4.0/
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Tipo de documento:
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Artículo Artículo - Versión publicada |
Editor:
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MDPI
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