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Perez-Ramos I.M.,IRNAS CSIC Av. Reina Mercedes | Diaz-Delgado R.,EBD CSIC c Americo Vespucio | de la Riva E.G.,University of Cordoba, Spain | Villar R.,University of Cordoba, Spain | And 2 more authors.
Journal of Ecology | Year: 2017

Understanding how different factors mediate the resistance of communities to climatic variability is a question of considerable ecological interest that remains mostly unresolved. This is particularly remarkable to improve predictions about the impact of climate change on vegetation. Here, we used a trait-based approach to analyse the sensitivity to climatic variability over 9 years of 19 Mediterranean shrubland communities located in southwest Spain. We evaluated the role of functional diversity (FD) and soil environment as drivers of community stability (assessed as changes in plant cover, species diversity and composition). The studied shrubland communities were strongly sensitive to inter-annual variability in climate. First, colder and drier conditions caused remarkable decreases in total plant cover but increased FD, likely because the reduction of plant cover after harsh climatic conditions promoted the expansion of functionally dissimilar species in the new open microsites; although communities returned to their initial values of plant cover after nine years, changes in FD and structure persisted over time. Second, drier and colder conditions favoured the predominance of shrubs with a conservative resource-use strategy (i.e. with higher dry matter content in leaves, stems and roots), bigger seeds and a more efficient use of water. The most functionally diverse communities were the most stable over time in terms of species diversity, likely because a higher number of functionally dissimilar species allowed compensatory dynamics among them. Communities inhabiting more acidic and resource-limited environments were less variable over time, probably because they were mainly constituted by slow-growth, stress-tolerant species that are potentially better adapted to harsh climatic conditions. Synthesis. This study highlights the utility of a trait-based approach to evaluate how plant communities respond to climatic variability. We could infer that the increased frequency of extreme climatic events predicted by climatic models will alter the functional structure of shrubland communities, with potential repercussions for ecosystem functioning. Our results also provide new insights into the role of FD and soil environment as buffers of the climate impact on woody communities, as well as potentially useful information to be applied in ecologically based management and restoration strategies. Journal of Ecology © 2017 British Ecological Society.


Llana-Ruiz-Cabello M.,University of Seville | Pichardo S.,University of Seville | Jimenez-Morillo N.T.,IRNAS CSIC Av. Reina Mercedes | Bermudez J.M.,Area of Packaging Materials and Systems ITENE C Albert Einstein 1 46980 Paterna | And 4 more authors.
Journal of the Science of Food and Agriculture | Year: 2015

BACKGROUND: Environmental, economic and safety challenges motivate shift towards safer materials for food packaging. New bioactive packaging techniques, i.e. addition of essential plant oils (EOs), are gaining attention by creating barriers to protect products from spoilage. Analytical pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) was used to fingerprint a bioactive polylactic acid (PLA) with polybutylene succinate (PBS) (950 g kg-1:50 g kg-1) film extruded with variable quantities (0, 20, 50 and 100 g kg-1) of Origanum vulgare EO. RESULTS: Main PLA:PBS pyrolysis products were lactide enantiomers and monomer units from the major PLA fraction and succinic acid anhydride from the PBS fraction. Oregano EO pyrolysis released cymene, terpinene and thymol/carvacrol peaks as diagnostic peaks for EO. In fact, linear correlation coefficients better than 0.950R2 value (P < 0.001) were found between the chromatographic area of the diagnostic peaks and the amount of oregano EO in the bioplastic. CONCLUSION: The pyrolytic behaviour of a bio-based active package polymer including EO is studied in detail. Identified diagnostic compounds provide a tool to monitor the quantity of EO incorporated into the PLA:PBS polymeric matrix. Analytical pyrolysis is proposed as a rapid technique for the identification and quantification of additives within bio-based plastic matrices. © 2015 Society of Chemical Industry.


Gonzalez-Perez J.A.,IRNAS CSIC Av. Reina Mercedes | Jimenez-Morillo N.T.,IRNAS CSIC Av. Reina Mercedes | de la Rosa J.M.,IRNAS CSIC Av. Reina Mercedes | Almendros G.,MNCN CSIC c Serrano 115 B 28006 Madrid Spain | Gonzalez-Vila F.J.,IRNAS CSIC Av. Reina Mercedes
Journal of the Science of Food and Agriculture | Year: 2015

BACKGROUND: Pyrolysis-compound specific isotopic analysis (Py-CSIA: Py-GC-(FID)-C-IRMS) is a relatively novel technique that allows on-line quantification of stable isotope proportions in chromatographically separated products released by pyrolysis. Validation of the Py-CSIA technique is compulsory for molecular traceability in basic and applied research. In this work, commercial sucrose from C4 (sugarcane) and C3 (sugarbeet) photosystem plants and admixtures were studied using analytical pyrolysis (Py-GC/MS), bulk δ13C IRMS and δ13C Py-CSIA. RESULTS: Major pyrolysis compounds were furfural (F), furfural-5-hydroxymethyl (HMF) and levoglucosan (LV). Bulk and main pyrolysis compound δ13C (‰) values were dependent on plant origin: C3 (F, -24.65 ± 0.89; HMF, -22.07 ± 0.41‰; LV, -21.74 ± 0.17‰) and C4 (F, -14.35 ± 0.89‰; HMF, -11.22 ± 0.54‰; LV, -11.44 ± 1.26‰). Significant regressions were obtained for δ13C of bulk and pyrolysis compounds in C3 and C4 admixtures. Furfural (F) was found 13C depleted with respect to bulk and HMF and LV, indicating the incorporation of the light carbon atom in position 6 of carbohydrates in the furan ring after pyrolysis. CONCLUSION: This is the first detailed report on the δ13C signature of major pyrolytically generated carbohydrate-derived molecules. The information provided by Py-CSIA is valuable for identifying source marker compounds of use in food science/fraud detection or in environmental research. © 2015 Society of Chemical Industry.

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