Peñuelas J, Filella I, Estiarte M, Ogaya R, Llusià J, Sardans J, Jump A, Curiel J, Carnicer J, Rutishauser T, Rico L, Keenan T, Garbulsky M, Coll M, Díaz de Quijano M, Seco R, Rivas-Ubach A, Silva J, Boada M, Stefanescu C, Lloret F, Terradas J (2010) Impactes, vulnerabilitat i retroalimentacions climàtiques als ecosistemes terrestres catalans. A: Llebot E. (ed). Segon informe sobre el canvi climàtic a Catalunya. Institut d'Estudis Catalans i Generalitat de Catalunya. pp. 373-407.
Llusià J., Peñuelas J., Ogaya R., Alessio G. (2010) Annual and seasonal changes in foliar terpene content and emission rates in cistus albidus L. submitted to soil drought in Prades Forest (Catalonia, NE Spain). Acta Physiologiae Plantarum. 32: 387-394.EnllaçDoi: 10.1007/s11738-009-0416-y
We measured the gas exchange and foliar terpene concentrations and terpene emission rates of Cistus albidus throughout the seasons of two annual periods (2003 and 2005) of contrasting precipitations (900 vs. 500 mm) and in response to experimental drought in a Mediterranean forest of southern Catalonia. C. albidus showed a typical seasonal oscillation of photosynthetic rates and stomatal conductance. Maximum photosynthetic activity appeared in the spring of the first year of the study and minimum ones in both summers. Net photosynthetic rates and stomatal conductance tended to decrease with drought treatment. In the first year, Cistus albidus presented maximum values of stored terpenes in autumn and winter and minimum values in spring and summer. Average concentrations in the first year were 154 and 96 μg g-1 dry matter (d.m.) for control and drought, respectively. Average concentrations in the second year were higher, 339 and 263 μg g-1 (d.m.) for control and drought, respectively. The most abundant terpene was zingiberene, followed by aromadendrene, germacrene, (-)-α-cedrene, and sesquiphel-landrene. The drought treatment tended to decrease terpene content, but not significantly. Considering all the treatments together, total terpene emissions ranged between practically 0 (spring 2003) to 9 μg g-1 (d.m.) h-1 (winter 2003). In the second year, total terpene emission rates decreased 39% in control plants, and 29% in drought plants. Significant seasonal differences in emission rates were found. Total emission rates tended to be higher in the drought treatment, especially in spring and autumn. These results help for a better understanding of the behavior of plant volatiles in Mediterranean conditions interannualy and seasonally, an issue of great interest for forest flammability and atmospheric chemistry. © Franciszek Górski Institute of Plant Physiology.
Sardans J, Peñuelas J, Ogaya R (2009) Climate change and drought: a threat for Mediterranean ecosystem. UAB DIVULGA 2009/02.
Peñuelas J, Filella I, Estiarte M, Ogaya R, Llusiè J, Sardans J, Jump A, Garbulsky M, Coll M, Díaz de Quijano M, Seco R, Blanch JS, Owen S, Curiel J, Carnicer J, Boada M, Stefanescu C, Lloret F, TerradasJ (2009) Constatacions biològiques del canvi climàtic a Catalunya. A “Aigua i canvi climàtic: Diagnosi dels impactes previstos a Catalunya” Generalitat de Catalunya, Departament de Medi Ambient i Habitatge, Agencia Catalana de l’Aigua, www.gencat.cat/aca .
Prieto P., Peñuelas J., Niinemets Ü., Ogaya R., Schmidt I.K., Beier C., Tietema A., Sowerby A., Emmett B.A., Láng E.K., Kröel-Dulay G., Lhotsky B., Cesaraccio C., Pellizzaro G., De Dato G., Sirca C., Estiarte M. (2009) Changes in the onset of spring growth in shrubland species in response to experimental warming along a north-south gradient in Europe. Global Ecology and Biogeography. 18: 473-484.EnllaçDoi: 10.1111/j.1466-8238.2009.00460.x
Aim: To test whether the onset of spring growth in European shrublands is advanced in response to the warmer conditions projected for the next two decades by climate models, and, if there is a change, whether it differs across Europe. Location: The studied sites spanned a broad north-south European gradient with average annual temperatures (8.2-15.6 °C) and precipitation (511-1427 mm). Methods: Bud break'was monitored in eight shrub and grass species in six European sites under control and experimentally warmer conditions generated by automatic roofs covering vegetation during the night. Results: Species responsive to increased temperatures were Vaccinium myrtillus and Empetrum nigrum in Wales, Deschampsia flexuosa in Denmark, Calluna vulgaris in Netherlands, Populus alba in Hungary and Erica multiflora in Spain. Although the acceleration of spring growth was the commonest response to warming treatments, the responses at each site were species specific and year dependent. Under experimental warming 25% of cases exhibited a significantly earlier onset of the growing season and 10% had a significantly delayed onset of vegetative growth. No geographical gradient was detected in the experimental warming effects. However, there was a trend towards a greater dominance of phenological advances with more intense the warming treatments. Above 0.8.°C warming, only advancements were recorded. Main conclusions: Our results show that warmer temperatures projected for the next decades have substantial potential effects on the phenology of the spring growth of dominant species in different European shrublands, with a dominant trend towards advancements the more intense the warming is. However, our study also demonstrates the overall difficulties of applying simple predictive relationships to extrapolate the effects of global change on phenology. Various combinations of environmental factors occur concurrently at different European sites and the interactions between different drivers (e.g. water and chilling) can alter phenology significantly. © 2009 Blackwell Publishing.
Alessio G.A., Peñuelas J., Llusià J., Ogaya R., Estiarte M., De Lillis M. (2008) Influence of water and terpenes on flammability in some dominant Mediterranean species. International Journal of Wildland Fire. 17: 274-286.EnllaçDoi: 10.1071/WF07038
In the Mediterranean basin, fires are a major concern for forest and shrubland ecosystems. We studied flammability, its seasonality and its relationship with leaf moisture and volatile terpene content and emission in the dominant species of a Mediterranean shrubland and forest in Catalonia (NE Iberian Peninsula). We measured temperatures and time elapsed between the three flammability phases: smoke, pyrolysis and flame, for four seasons. We sampled twice in spring because of an occasional drought period during this season. Flammability had a significant relationship with leaf hydration, in the shrubland and in the forest. Few and only weak correlations were found between terpene content and flammability. In the future, arid conditions projected by climatic and ecophysiological models will increase fire risk through decreased hydration and subsequent increased flammability of the species. © IAWF 2008.
Sardans J, Peñuelas J, Ogaya R (2008) Drought-induced changes in C and N stoichiometry in a Quercus ilex Mediterranean forest . Forest Science 54: 513-522
Peñuelas J, Filella I, Estiarte M, Ogaya R, Llusià J, Sardans J, Jump A, Garbulsky M, Carrillo B, Stefanescu C, Lloret F, Terradas J (2008) El canvi climàtic altera i alterarà la vida als ecosistemes terrestres Catalans. L'Atzavara 16: 13-28.
Peñuelas J, Filella I, Estiarte M, Ogaya R, LLusià J, Sardans J, Jump A, Garbulsky M, Coll M, Diaz de Quijano M, Seco R, Salvador Blanch J, Owen S, Curiel J, Carnicer J, Boada M, Stefanescu C, Lloret F, Terradas J (2008) Climate change and phenology, adaptation, migration and extinction in plant species.In Climate Change and Systematics, Trinity College Dublin pp. 16.
Peñuelas J, Jump A, Sardans J, Filella I, Estiarte M, Ogaya R, Llusià J, Owen S, Lloret F (2008) From Phosphorous and VOCs to Biodiversity: some studies on the effects of global change inspired by Margalef’s legacy. (2008).. In: F. Valladares, A. Camacho, A. Elosegi, C. Gracia, M. Estrada, J.C. Senar, J.M. Gili (eds.), Unity in Diversity. Reflection s on Ecology after the legacy of Ramon Margalef, pp. 83-94. Fundación BBVA, Bilbao.
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