Peñuelas J, Sardans J, Ogaya R, Estiarte M (2008) Nutrient stoichiometric relations and biogeochemical niche in coexisting plant species: effect of simulated climate change. Polish Journal of Ecology 56: 613-622.
Peñuelas J, Prieto P, Llorens L, Estiarte M (2008) Científics del CREAF mostren els efectes del canvi climàtic en un experiment de camp. UAB DIVULGA 01/2008
Kovács-Láng E, Peñuelas J, Estiarte M, Prieto P, Llorens L (2008) VULCAN Project: Scientists for preventing and moderating the dangers of climate change in cooperation with the society. European City of Sciences 2008. Paris.
Peñuelas J, Estiarte M, Prieto P, Sardans J, Moreno JM, Torres I, Céspedes B, Pla E, Sabaté S, Gracia C (2008) Impacts on biodiversity of Mediterranean ecosystems. In Settele, J. et al. (eds.) (in prep.): Atlas of Biodiversity Risks - from Europe to the globe, from stories to maps. Pensoft, Sofia & Moscow (www.pensoftonline.net/alarm-atlas-info) pp.76-77.
Jump A.S., Peñuelas J., Rico L., Ramallo E., Estiarte M., Martínez-Izquierdo J.A., Lloret F. (2008) Simulated climate change provokes rapid genetic change in the Mediterranean shrub Fumana thymifolia. Global Change Biology. 14: 637-643.LinkDoi: 10.1111/j.1365-2486.2007.01521.x
Rapid climate change will impose strong directional selection pressures on natural plant populations. Climate-linked genetic variation in natural populations indicates that an evolutionary response is possible. We investigated such a response by comparing individuals subjected to elevated drought and warming treatments with individuals establishing in an unmanipulated climate within the same population. We report that reduction in seedling establishment in response to climate manipulations is nonrandom and results from the selection pressure imposed by artificially warmed and droughted conditions. When compared against control samples, high single-locus genetic divergence occurred in drought and warming treatment samples, with genetic differentiation up to 37 times higher than background (mean neutral locus) genetic differentiation. These loci violate assumptions of selective neutrality, indicating the signature of natural selection by drought. Our results demonstrate that rapid evolution in response to climate change may be widespread in natural populations, based on genetic variation already present within the population. © 2008 The Authors Journal compilation © 2008 Blackwell Publishing Ltd.
Estiarte M, Peñuelas J, Sardans J, Emmett BA, Sowerby A, Beier C, Schmidt IK, Tietema A, Van Meeteres MJM, Kovacs Lang E, Mathe P, De Angelis P, De Dato G (2008) Root-surface phosphatase activity in shrublands across a European gradient: Effects of warming. Journal Environmental Biology 29: 25-29.
Prieto P., Peñuelas J., Ogaya R., Estiarte M. (2008) Precipitation-dependent flowering of Globularia alypum and Erica multiflora in Mediterranean shrubland under experimental drought and warming, and its inter-annual variability. Annals of Botany. 102: 275-285.LinkDoi: 10.1093/aob/mcn090
• Background and Aims: Relationships between autumn flowering, precipitation and temperature of plant species of Mediterranean coastal shrublands have been described, but not analysed experimentally. These relationships were analysed for two species of co-occurring, dominant, autumn-flowering shrubs, Globularia alypum and Erica multiflora, over 4 years and in experimentally generated drought and warming conditions. The aim was to improve predictions about the responses and adaptations of flowering of Mediterranean vegetation to climate change. • Methods: Beginning of anthesis and date of maximum flowering intensity ('peak date') were monitored over 4 years (2001-2004) on a garrigue land type in the noth-east of the Iberian Peninsula. Two experimental treatments were applied, increased temperature (+0.73°C) and reduced soil moisture (-17%) relative to untreated plots. • Key Results: Flowering of Globularia alypum and Erica multiflora differed greatly between years depending on the precipitation of the previous months and the date of the last substantial rainfall (>10 mm). Globularia alypum flowered once or twice (unimodal or bimodal) as the result of differences in the distribution and magnitude of precipitation in late-spring and summer (when floral buds develop). The drought treatment delayed and decreased flowering of Globularia alypum in 2001 and delayed flowering in 2002. Warming extended the period between the beginning of flowering and the end of the second peak for autumn flowering in 2001 and also increased peak intensity in 2002. Flowering of Erica multiflora was unaffected by either treatment. • Conclusions: Autumn flowering of Globularia alypum and Erica multiflora is more dependent on water availability than on temperature. Considerable inter-annual plasticity in the beginning of anthesis and peak date and on unimodal or bimodal flowering constitutes a 'safe strategy' for both species in relation to varying precipitation and temperature. However, severe changes in precipitation in spring and summer may severely affect flowering of Globularia alypum but not Erica multiflora, thus affecting development/structure of the ecosystem if such conditions persist. © The Author 2008. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.
Sardans J., Peñuelas J., Estiarte M. (2008) Warming and drought change trace element bioaccumulation patterns in a Mediterranean shrubland. Chemosphere. 70: 874-885.LinkDoi: 10.1016/j.chemosphere.2007.06.085
A field experiment consisting of drought and warming manipulation was conducted in a Mediterranean shrubland dominated by the shrubs Erica multiflora and Globularia alypum. The aim was to investigate the effects of the climatic changes predicted by IPCC models for the coming decades on trace element concentration and accumulation in aboveground biomass, plant litter, and soil. Warming increased concentrations and aboveground accumulation of some trace elements related to plant root uptake, such as Al, As, Cr, Cu, and partially Pb. This effect was more general in E. multiflora than in G. alypum. The stronger effects were increases in Al leaf concentrations (42%) and aboveground accumulation (500 g ha-1) in E. multiflora, in As stem biomass accumulation (0.2 g ha-1) in E. multiflora, and in Cr leaf concentrations (51%) in G. alypum and stem aboveground accumulation in E. multiflora (1.1 g ha-1). These species-specific increases were related to greater retranslocation, photosynthetic capacity and growth in E. multiflora than in G. alypum. Warming decreased the concentrations of some trace elements in leaf litter, implying the existence of an increased leaf retranslocation. Drought increased As (40%) and Cd (55%) in E. multiflora stems, whereas it decreased Cu (50%) in leaves, Ni (28%) in stems and Pb (32%) in leaf litter of G. alypum. The increasing concentrations of some trace elements in E. multiflora and not in G. alypum were related to a greater growth reduction in E. multiflora than in G. alypum. Warming increased As soil solubility (67%) and decreased total soil As (21%). Those changes were related to a greater Fe mobilization in warming plot and to a greater plant capture. Drought increased Hg (350%) concentrations in soils but had no significant effects on trace element accumulation in aboveground biomass. The different response to warming and drought in the two dominant species implies uneven changes in the quality of the plant tissues that may have implications for herbivores. This may be specially important for the performance of the studied Mediterranean ecosystems under the warmer and drier conditions predicted by the next decades by the GCM and ecophysiological models. © 2007 Elsevier Ltd. All rights reserved.
Sardans J., Peñuelas J., Estiarte M. (2008) Changes in soil enzymes related to C and N cycle and in soil C and N content under prolonged warming and drought in a Mediterranean shrubland. Applied Soil Ecology. 39: 223-235.LinkDoi: 10.1016/j.apsoil.2007.12.011
In a Mediterranean shrubland, we investigated the effects of the projected warming and drought on soil urease, protease and β-glucosidase activities and the relation of the possible changes in the activities of these enzymes with the observed changes in soil moisture, soil pH and in C and N stocks in soils, leaves and leaf litter during 1 year (April 2004-May 2005). This investigation was conducted in a long-term experiment of warming and drought manipulation that began in 1999 and is lasting until now. Warming increased soil urease activity by 10% in the study period, mainly by increasing soil urease activity 30% in winter and 10% in spring, and increased β-glucosidase activity 38% in spring. Soil urease and β-glucosidase activities were positively correlated with soil temperatures in winter and negatively in summer. Warming increased soil enzyme activities in winter when soil moisture was highest and in spring coinciding with the greatest biological activity. Warming decreased NH4 + soil concentration in the spring of 2004 (by 30%) and 2005 (by 72%), in consonance with the increase in N uptake by plants. Warming decreased N concentration in Globularia alypum leaf litter, increasing C/N leaf ratio by 30% showing an increase in N mobilization and contributing to a greater total N accumulation in plants. However, the greater NO3 - availability in soil observed under warming, probably by an increase in nitrification, may lead to a net N loss by leaching under the torrential rainfalls typical of the Mediterranean climate regions. Drought reduced soil protease activity (9%) in the study period, mainly by decreasing it in spring by 13-21%, but did not affect N soil contents because N turn-over reduction was counterbalanced by a decrease in N leaf concentrations. Soil protease activity was positively correlated with soil water content showing a strong dependence of this enzyme on soil water content. Drought did not affect β-glucosidase activity but tended to increase C contents in soils, which together with the increase in C/N in leaves indicate a reduction of C turn-over and a trend to increase C stocks in soil at long term. The effects of warming and drought on soil enzyme activities were due to a direct effect on soil temperature and soil water content, respectively, and not to changes on soil organic matter quantity and nutritional quality. © 2008 Elsevier B.V. All rights reserved.
Sardans J., Peñuelas J., Estiarte M., Prieto P. (2008) Erratum: Warming and drought alter C and N concentration, allocation and accumulation in a Mediterranean shrubland (Global Change Biology). Global Change Biology. 14: 2771-0.LinkDoi: 10.1111/j.1365-2486.2008.01717.x
[No abstract available]
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