Peñuelas J, Filella I, Farré G, Owen S, Primante C, Rodrigo A, Martín A, Bosch J, Seco R, Porcar A, Llusià J, Greenberg J, Harley P, Rapparini F, Estiarte M, Mejia-Chang M, Ogaya R, Ibañez J, Sardans J, Turnipseed A, Geron C, Duhl T, Facini O, Baraldi R, Rapparini F, Guenther A (2012) BVOCs in the plant-pollinator market and other applications of ecology to betytyerunderstand BVOC emissions in the environment. BVOCs Gordon Conference, Biogenic Hydrocarbons & the atmosphere. Reaching across scales: from molecule to the globe. Bates College, Maine. June 24-29. Key note invited speaker.
Peñuelas J, Filella I, Estiarte M, Ogaya R, Llusià J, Sardans J, Jump A, Carnicer J, Rico L, Garbulsky M, Coll M, Díaz de Quijano M, Seco R, Rivas-Ubach A, Kefauver S, Barbeta A, Achoategui A, Mejía-Chang M, Gallardo A, Farre G, Fernández M, Terradas J (2012) Ecosystemic and biospheric interactions with carbon cycle. In Carbon dioxide budget: processes and tendencies symposium. Universitat Politècnica de Catalunya, May 23-25.
Estiarte M, Peñuelas J, Ogaya R (2012) Mediterranean shrubland and forest responses to experimental drought. Drought and ohter extreme weather conditions in terrestrial ecosystems. CLIMMANI European Science foundation. Dubrovnic. June 6-8.
Estiarte M, Peñuelas J, Ogaya R, Barbeta A (2012) Experimental drought experiments in Garraf and Prades. Results of long-term field experiments. In: Drought and other extreme weather conditions in terrestrial ecosystems, CLIMANI workshop. Dubrovnik, Croatia. June 6-8.
Nogués I., Peñuelas J., Llusià J., Estiarte M., Munné-Bosch S., Sardans J., Loreto F. (2012) Physiological and antioxidant responses of Erica multiflora to drought and warming through different seasons. Plant Ecology. 213: 649-661.EnllaçDoi: 10.1007/s11258-012-0029-1
Climate change projections forecast a warming and an associated change in the distribution and intensity of rainfalls. In the case of the Mediterranean area, this will be reflected in more frequent and severe drought periods in the future. Within a long-term (9 years) manipulation experiment, we aimed to study the effect of the soil drought (15-20% decreased soil moisture) and warming conditions (+1°C warming) projected for the next decades onto photosynthetic rates and water relations, and onto the antioxidant and anti-stress defense capacity of Erica multiflora, a common species of the dry Mediterranean coastal scrublands, in two different seasons, spring and summer. Results indicated that none of the applied treatments was severe enough to induce a pronounced negative response of photosynthesis in this species well adapted to harsh Mediterranean conditions, but also highlighted important seasonal differences. Photosynthesis was limited by photoinhibition in spring and by stomatal closure in summer. Isoprenoid emission and the level of enzymatic and non-enzymatic antioxidants were lower in summer than in spring, whereas pigment and total phenolic contents were generally higher in summer. Volatile isoprenoid emissions were largely inhibited by drought and were not stimulated by warming. Drought and warming increased the oxidation state of ascorbate and reduced total glutathione levels in spring, but not in summer. It is concluded that E. multiflora plants can adapt to prolonged drought and warming, at least at the level simulated by our manipulative experiment, through changes in the seasonal physiological and antioxidant response of leaves. © 2012 Springer Science+Business Media B.V.
Saura-Mas S., Estiarte M., Peñuelas J., Lloret F. (2012) Effects of climate change on leaf litter decomposition across post-fire plant regenerative groups. Environmental and Experimental Botany. 77: 274-282.EnllaçDoi: 10.1016/j.envexpbot.2011.11.014
Decomposition is a determining factor for the functioning of ecosystems because litter dynamics (litter fall and litter decomposition) constitute a key process in the regulation of the recycling of carbon and nutrients. We studied the litter decomposition properties of a set of 19 Mediterranean-basin woody species with different post-fire regenerative strategies (resprouters and non-resprouters), under experimental climate manipulation (simulating warming and drought) over a 2-year period. We show that climate change modifies litter decomposition of these Mediterranean woody species as litter contributions to the soil (g/year) were lower under drought experimental conditions. Species with different post-fire regeneration performance showed different leaf decomposition patterns, though these patterns were influenced by the taxonomical affiliation of the species. As expected, the mass loss of the non-resprouter litter, after 2 years, was higher than in resprouters. Non-resprouters showed higher nutrient concentration per mass of leaf litter after 2 years of experiment than resprouters, possibly because they have lost more C-rich biomass, allowing high nutrients concentration in the remaining litter. That would apply particularly to P as litter N:P ratio was lower in non-resprouters than in resprouters. This study suggests that, in Mediterranean ecosystems, nutrients' return from leaf litter to the soil will be slower under the projected future drier conditions. Furthermore, changes in fire regimes that lead to modifications in the abundance of post-fire regenerative groups are likely to affect ecosystem's functional properties. Thus, if new fire regimes enhance non-resprouters' abundance, we can expect a greater return of organic matter contributions to the soil and a lower litter N:P. © 2011 Elsevier B.V.
Vicca S., Gilgen A.K., Camino Serrano M., Dreesen F.E., Dukes J.S., Estiarte M., Gray S.B., Guidolotti G., Hoeppner S.S., Leakey A.D.B., Ogaya R., Ort D.R., Ostrogovic M.Z., Rambal S., Sardans J., Schmitt M., Siebers M., van der Linden L., van Straaten O., Granier A. (2012) Urgent need for a common metric to make precipitation manipulation experiments comparable. New Phytologist. 195: 518-522.EnllaçDoi: 10.1111/j.1469-8137.2012.04224.x
[No abstract available]
del Cacho M., Saura-Mas S., Estiarte M., Peñuelas J., Lloret F. (2012) Effect of experimentally induced climate change on the seed bank of a Mediterranean shrubland. Journal of Vegetation Science. 23: 280-291.EnllaçDoi: 10.1111/j.1654-1103.2011.01345.x
Questions: We studied the soil seed bank under field-simulated climate change conditions and addressed the following questions: Is the effect of climate change on seed banks more evident in areas without vegetation? Are short-lived species more sensitive to this directional climate change than long-lived species? Location: A Mediterranean shrubland in the Garraf Natural Park, NE Spain. Methods: Directional climate change was induced through manipulating temperature and rainfall over almost 9 yr. Soil seed banks were assessed using the seedling emergence method. Results: Under drought and warming treatments, the total number of germinating seeds decreased by 47% and 43%, respectively, in non-vegetated areas. In contrast, no effect was found for areas with vegetation cover. Reduced seed bank density was particularly pronounced for short-lived species (therophytes plus hemicryptophytes), which dropped by 60% and 69%, respectively, in the drought and warming treatments in open areas, while no significant changes were observed under vegetation. In non-vegetated areas, the reduction in seed bank density was similar in all species. In contrast, a shift in the relative abundance of seed bank species was apparent under shrub canopies. Conclusions: As experimental climatic manipulations of Mediterranean shrublands demonstrate a trend towards an increase in open areas under drought conditions, a decrease in the seed bank of short-lived species in these areas may potentially result in a positive feedback that would accentuate the loss of vegetation cover under predicted future climate conditions. © 2011 International Association for Vegetation Science.
Bernal M., Estiarte M., Peñuelas J. (2011) Drought advances spring growth phenology of the Mediterranean shrub Erica multiflora. Plant Biology. 13: 252-257.EnllaçDoi: 10.1111/j.1438-8677.2010.00358.x
Current climate projections predict drier and warmer conditions in the Mediterranean basin over the next century. While advanced spring growth due to warming has been described in the literature, few data are available on the effects of drought on phenology. Hence, the phenology and growth of two Mediterranean shrubs, Erica multiflora and Globularia alypum, was studied in a rainfall exclusion field experiment to simulate spring drought in a natural shrubland. We estimated the onset of growth in spring by monitoring the appearance of new stems, and the end of growth in summer by following the elongation of stems. Drought treatment caused earlier onset of the spring growing season in E. multiflora, whereas no advance was observed in G. alypum. However, growth cessation was not affected in E. multiflora. Drought reduced the growth of both shrubs, as reflected in less stem elongation. The results show that a drier climate might affect not only growth but also spring phenology of some Mediterranean species. We suggest that a reduction in the cooling effect of transpiration may have analogous effects to warming and might advance the start of growth in E. multiflora, a species whose phenology has been described as warming-sensitive. The lengthening of the growing season resulting from advanced growth did not imply higher productivity, as growth was restricted by drought. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.
Estiarte M., Puig G., Peñuelas J. (2011) Large delay in flowering in continental versus coastal populations of a Mediterranean shrub, Globularia alypum. International Journal of Biometeorology. 55: 855-865.EnllaçDoi: 10.1007/s00484-011-0422-9
Globularia alypum is a perennial shrub typical of western Mediterranean thermophilous shrublands. Nine populations of G. alypum located in different localities of Catalonia (NE Spain) were surveyed for flowering phenology. Flower-head buds were present in all the populations in July. Flowering time in the area spans from the late summer-early autumn to the next spring depending on the populations; there are two groups of populations, early and late flowering. Early populations grow mostly in coastal localities and flower from September to November, whereas late flowering populations grow in inland localities and flower from February to April. The flowering order of the populations correlated with minimum temperature of most months except the warmest ones, and correlated with maximum and mean temperatures of the coldest months. Correlations were similar when tested with annual climate. The flowering order also correlated with the thermic interval for most months except the coldest and with the index of continentality. Early populations alone did not present correlations with any variable, whereas late populations alone correlated similarly to all populations together. Flowering order did not correlate with precipitation. Late populations are proposed to be regulated by temperature according to our results whereas early populations could be regulated by timing in precipitation after summer drought, according to published results. We discuss the possibilities of the two flowering patterns, early and late, being due to phenotypic plasticity or to genetic adaptation to local climates. We also discuss the consequences at the plant and ecosystem level of climate warming causing shifts from late to early patterns, a possibility that is likely in the warmest of the late populations if flowering is modulated phenotypically. © 2011 ISB.
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