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Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability

Differences in litter quality, microbial activity or abiotic conditions cannot fully account for the variability in decomposition rates observed in semiarid ecosystems. Here we tested the role of variation in litter quality, water supply, and UV radiation as drivers of litter decomposition in arid l...

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Autores principales: Gaxiola, Aurora, Armesto, Juan J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4362295/
https://www.ncbi.nlm.nih.gov/pubmed/25852705
http://dx.doi.org/10.3389/fpls.2015.00140
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author Gaxiola, Aurora
Armesto, Juan J.
author_facet Gaxiola, Aurora
Armesto, Juan J.
author_sort Gaxiola, Aurora
collection PubMed
description Differences in litter quality, microbial activity or abiotic conditions cannot fully account for the variability in decomposition rates observed in semiarid ecosystems. Here we tested the role of variation in litter quality, water supply, and UV radiation as drivers of litter decomposition in arid lands. And show that carry-over effects of litter photodegradation during dry periods can regulate decomposition during subsequent wet periods. We present data from a two-phase experiment, where we first exposed litter from a drought-deciduous and an evergreen shrub to natural UV levels during five, rainless summer months and, subsequently, in the laboratory, we assessed the carry-over effects of photodegradation on biomass loss under different irrigation treatments representing the observed range of local rainfall variation among years (15–240 mm). Photodegradation of litter in the field produced average carbon losses of 12%, but deciduous Proustia pungens lost >25%, while evergreen Porlieria chilensis less than 5%. Natural exposure to UV significantly reduced carbon-to-nitrogen and lignin:N ratios in Proustia litter but not in Porlieria. During the subsequent wet phase, remaining litter biomass was lower in Proustia than in Porlieria. Indeed UV exposure increased litter decomposition of Proustia under low and medium rainfall treatments, whereas no carry-over effects were detected under high rainfall treatment. Consequently, for deciduous Proustia carry-over effects of UV exposure were negligible under high irrigation. Litter decomposition of the evergreen Porlieria depended solely on levels of rainfall that promote microbial decomposers. Our two-phase experiment revealed that both the carry-over effects of photodegradation and litter quality, modulated by inter-annual variability in rainfall, can explain the marked differences in decomposition rates and the frequent decoupling between rainfall and litter decomposition observed in semiarid ecosystems.
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spelling pubmed-43622952015-04-07 Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability Gaxiola, Aurora Armesto, Juan J. Front Plant Sci Plant Science Differences in litter quality, microbial activity or abiotic conditions cannot fully account for the variability in decomposition rates observed in semiarid ecosystems. Here we tested the role of variation in litter quality, water supply, and UV radiation as drivers of litter decomposition in arid lands. And show that carry-over effects of litter photodegradation during dry periods can regulate decomposition during subsequent wet periods. We present data from a two-phase experiment, where we first exposed litter from a drought-deciduous and an evergreen shrub to natural UV levels during five, rainless summer months and, subsequently, in the laboratory, we assessed the carry-over effects of photodegradation on biomass loss under different irrigation treatments representing the observed range of local rainfall variation among years (15–240 mm). Photodegradation of litter in the field produced average carbon losses of 12%, but deciduous Proustia pungens lost >25%, while evergreen Porlieria chilensis less than 5%. Natural exposure to UV significantly reduced carbon-to-nitrogen and lignin:N ratios in Proustia litter but not in Porlieria. During the subsequent wet phase, remaining litter biomass was lower in Proustia than in Porlieria. Indeed UV exposure increased litter decomposition of Proustia under low and medium rainfall treatments, whereas no carry-over effects were detected under high rainfall treatment. Consequently, for deciduous Proustia carry-over effects of UV exposure were negligible under high irrigation. Litter decomposition of the evergreen Porlieria depended solely on levels of rainfall that promote microbial decomposers. Our two-phase experiment revealed that both the carry-over effects of photodegradation and litter quality, modulated by inter-annual variability in rainfall, can explain the marked differences in decomposition rates and the frequent decoupling between rainfall and litter decomposition observed in semiarid ecosystems. Frontiers Media S.A. 2015-03-17 /pmc/articles/PMC4362295/ /pubmed/25852705 http://dx.doi.org/10.3389/fpls.2015.00140 Text en Copyright © 2015 Gaxiola and Armesto. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Plant Science
Gaxiola, Aurora
Armesto, Juan J.
Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability
title Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability
title_full Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability
title_fullStr Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability
title_full_unstemmed Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability
title_short Understanding litter decomposition in semiarid ecosystems: linking leaf traits, UV exposure and rainfall variability
title_sort understanding litter decomposition in semiarid ecosystems: linking leaf traits, uv exposure and rainfall variability
topic Plant Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4362295/
https://www.ncbi.nlm.nih.gov/pubmed/25852705
http://dx.doi.org/10.3389/fpls.2015.00140
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