Can trees buffer the impact of climate change on pasture production and digestibility of Mediterranean dehesas?

Hidalgo-Galvez Maria Dolores, Barkaoui Karim, Volaire Florence, Matías Luis, Cambrollé Jesús, Fernández-Rebollo Pilar, Carbonero Maria Dolores, Pérez-Ramos Ignacio Manuel. 2022. Can trees buffer the impact of climate change on pasture production and digestibility of Mediterranean dehesas?. Science of the Total Environment, 835:0048-9697, 15 p.

https://doi.org/10.1016/j.scitotenv.2022.155535

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Résumé : Sustainability and functioning of silvopastoral ecosystems are being threatened by the forecasted warmer and drier environments in the Mediterranean region. Scattered trees of these ecosystems could potentially mitigate the impact of climate change on herbaceous plant community but this issue has not yet tested experimentally. We carried out a field manipulative experiment of increased temperature (+2–3 °C) using Open Top Chambers and rainfall reduction (30%) through rain-exclusion shelters to evaluate how net primary productivity and digestibility respond to climate change over three consecutive years, and to test whether scattered trees could buffer the effects of higher aridity in Mediterranean dehesas. First, we observed that herbaceous communities located beneath tree canopy were less productive (351 g/m2) than in open grassland (493 g/m2) but had a higher digestibility (44% and 41%, respectively), likely promoted by tree shade and the higher soil fertility of this habitat. Second, both habitats responded similarly to climate change in terms of net primary productivity, with a 33% increase under warming and a 13% decrease under reduced rainfall. In contrast, biomass digestibility decreased under increased temperatures (−7.5%), since warming enhanced the fiber and lignin content and decreased the crude protein content of aerial biomass. This warming-induced effect on biomass digestibility only occurred in open grasslands, suggesting a buffering role of trees in mitigating the impact of climate change. Third, warming did not only affect these ecosystem processes in a direct way but also indirectly via changes in plant functional composition. Our findings suggest that climate change will alter both the quantity and quality of pasture production, with expected warmer conditions increasing net primary productivity but at the expense of reducing digestibility. This negative effect of warming on digestibility might be mitigated by scattered trees, highlighting the importance of implementing strategies and suitable management to control tree density in these ecosystems.

Mots-clés Agrovoc : atténuation des effets du changement climatique, productivité des terres, pâturages, évaluation de l'impact, changement climatique, digestibilité, écosystèmes arides, caractère agronomique, climat méditerranéen

Mots-clés géographiques Agrovoc : Espagne

Mots-clés libres : Agroforestry, Drought, Herbivory, Plant functional traits, Water balance

Classification Agris : P40 - Météorologie et climatologie
F60 - Physiologie et biochimie végétale

Champ stratégique Cirad : CTS 6 (2019-) - Changement climatique

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