TY - JOUR A1 - Lecourieux, Fatma A1 - Kappel, Christian A1 - Pieri, Philippe A1 - Charon, Justine A1 - Pillet, Jeremy A1 - Hilbert, Ghislaine A1 - Renaud, Christel A1 - Gomes, Eric A1 - Delrot, Serge A1 - Lecourieux, David T1 - Dissecting the Biochemical and Transcriptomic Effects of a Locally Applied Heat Treatment on Developing Cabernet Sauvignon Grape Berries JF - Frontiers in plant science N2 - Reproductive development of grapevine and berry composition are both strongly influenced by temperature. To date, the molecular mechanisms involved in grapevine berries response to high temperatures are poorly understood. Unlike recent data that addressed the effects on berry development of elevated temperatures applied at the whole plant level, the present work particularly focuses on the fruit responses triggered by direct exposure to heat treatment (HT). In the context of climate change, this work focusing on temperature effect at the microclimate level is of particular interest as it can help to better understand the consequences of leaf removal (a common viticultural practice) on berry development. HT (+8 degrees C) was locally applied to clusters from Cabernet Sauvignon fruiting cuttings at three different developmental stages (middle green, veraison and middle ripening). Samples were collected 1, 7, and 14 days after treatment and used for metabolic and transcriptomic analyses. The results showed dramatic and specific biochemical and transcriptomic changes in heat exposed berries, depending on the developmental stage and the stress duration. When applied at the herbaceous stage, HT delayed the onset of veraison. Heating also strongly altered the berry concentration of amino acids and organic acids (e.g., phenylalanine, raminobutyric acid and malate) and decreased the anthocyanin content at maturity. These physiological alterations could be partly explained by the deep remodeling of transcriptome in heated berries. More than 7000 genes were deregulated in at least one of the nine experimental conditions. The most affected processes belong to the categories "stress responses," protein metabolism" and "secondary metabolism," highlighting the intrinsic capacity of grape berries to perceive HT and to build adaptive responses. Additionally, important changes in processes related to "transport," "hormone" and "cell wall" might contribute to the postponing of veraison. Finally, opposite effects depending on heating duration were observed for genes encoding enzymes of the general phenylpropanoid pathway, suggesting that the HI induced decrease in anthocyanin content may result from a combination of transcript abundance and product degradation. KW - grapevine KW - berry development KW - microclimate KW - high temperature KW - microarrays KW - metabolomics/metabolite profiling KW - climate change Y1 - 2017 U6 - https://doi.org/10.3389/fpls.2017.00053 SN - 1664-462X VL - 8 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Meißl, Gertraud A1 - Formayer, Herbert A1 - Klebinder, Klaus A1 - Kerl, Florian A1 - Schöberl, Friedrich A1 - Geitner, Clemens A1 - Markart, Gerhard A1 - Leidinger, David A1 - Bronstert, Axel T1 - Climate change effects on hydrological system conditions influencing generation of storm runoff in small Alpine catchments JF - Hydrological processes : an international journal N2 - Floods and debris flows in small Alpine torrent catchments (<10km(2)) arise from a combination of critical antecedent system state conditions and mostly convective precipitation events with high precipitation intensities. Thus, climate change may influence the magnitude-frequency relationship of extreme events twofold: by a modification of the occurrence probabilities of critical hydrological system conditions and by a change of event precipitation characteristics. Three small Alpine catchments in different altitudes in Western Austria (Ruggbach, Brixenbach and Langentalbach catchment) were investigated by both field experiments and process-based simulation. Rainfall-runoff model (HQsim) runs driven by localized climate scenarios (CNRM-RM4.5/ARPEGE, MPI-REMO/ECHAM5 and ICTP-RegCM3/ECHAM5) were used in order to estimate future frequencies of stormflow triggering system state conditions. According to the differing altitudes of the study catchments, two effects of climate change on the hydrological systems can be observed. On one hand, the seasonal system state conditions of medium altitude catchments are most strongly affected by air temperature-controlled processes such as the development of the winter snow cover as well as evapotranspiration. On the other hand, the unglaciated high-altitude catchment is less sensitive to climate change-induced shifts regarding days with critical antecedent soil moisture and desiccated litter layer due to its elevation-related small proportion of sensitive areas. For the period 2071-2100, the number of days with critical antecedent soil moisture content will be significantly reduced to about 60% or even less in summer in all catchments. In contrast, the number of days with dried-out litter layers causing hydrophobic effects will increase by up to 8%-11% of the days in the two lower altitude catchments. The intensity analyses of heavy precipitation events indicate a clear increase in rain intensities of up to 10%. KW - climate change KW - hydrophobic effects KW - small Alpine catchments KW - soil moisture KW - storm runoff events KW - system conditions Y1 - 2016 U6 - https://doi.org/10.1002/hyp.11104 SN - 0885-6087 SN - 1099-1085 VL - 31 IS - 6 SP - 1314 EP - 1330 PB - Wiley CY - New York ER - TY - JOUR A1 - Markovic, Danijela A1 - Carrizo, Savrina F. A1 - Kaercher, Oskar A1 - Walz, Ariane A1 - David, Jonathan N. W. T1 - Vulnerability of European freshwater catchments to climate change JF - Global change biology N2 - Climate change is expected to exacerbate the current threats to freshwater ecosystems, yet multifaceted studies on the potential impacts of climate change on freshwater biodiversity at scales that inform management planning are lacking. The aim of this study was to fill this void through the development of a novel framework for assessing climate change vulnerability tailored to freshwater ecosystems. The three dimensions of climate change vulnerability are as follows: (i) exposure to climate change, (ii) sensitivity to altered environmental conditions and (iii) resilience potential. Our vulnerability framework includes 1685 freshwater species of plants, fishes, molluscs, odonates, amphibians, crayfish and turtles alongside key features within and between catchments, such as topography and connectivity. Several methodologies were used to combine these dimensions across a variety of future climate change models and scenarios. The resulting indices were overlaid to assess the vulnerability of European freshwater ecosystems at the catchment scale (18 783 catchments). The Balkan Lakes Ohrid and Prespa and Mediterranean islands emerge as most vulnerable to climate change. For the 2030s, we showed a consensus among the applied methods whereby up to 573 lake and river catchments are highly vulnerable to climate change. The anthropogenic disruption of hydrological habitat connectivity by dams is the major factor reducing climate change resilience. A gap analysis demonstrated that the current European protected area network covers <25% of the most vulnerable catchments. Practical steps need to be taken to ensure the persistence of freshwater biodiversity under climate change. Priority should be placed on enhancing stakeholder cooperation at the major basin scale towards preventing further degradation of freshwater ecosystems and maintaining connectivity among catchments. The catchments identified as most vulnerable to climate change provide preliminary targets for development of climate change conservation management and mitigation strategies. KW - catchment connectivity KW - climate change KW - exposure KW - freshwater biodiversity KW - gap analysis KW - resilience KW - sensitivity KW - vulnerability Y1 - 2017 U6 - https://doi.org/10.1111/gcb.13657 SN - 1354-1013 SN - 1365-2486 VL - 23 SP - 3567 EP - 3580 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Wieczorek, Mareike A1 - Kruse, Stefan A1 - Epp, Laura Saskia A1 - Kolmogorov, Alexei A1 - Nikolaev, Anatoly N. A1 - Heinrich, Ingo A1 - Jeltsch, Florian A1 - Pestryakova, Luidmila Agafyevna A1 - Zibulski, Romy A1 - Herzschuh, Ulrike T1 - Dissimilar responses of larch stands in northern Siberia to increasing temperatures-a field and simulation based study JF - Ecology : a publication of the Ecological Society of America N2 - Arctic and alpine treelines worldwide differ in their reactions to climate change. A northward advance of or densification within the treeline ecotone will likely influence climate-vegetation feedback mechanisms. In our study, which was conducted in the Taimyr Depression in the North Siberian Lowlands, w present a combined field-and model-based approach helping us to better understand the population processes involved in the responses of the whole treeline ecotone, spanning from closed forest to single-tree tundra, to climate warming. Using information on stand structure, tree age, and seed quality and quantity from seven sites, we investigate effects of intra-specific competition and seed availability on the specific impact of recent climate warming on larch stands. Field data show that tree density is highest in the forest-tundra, and average tree size decreases from closed forest to single-tree tundra. Age-structure analyses indicate that the trees in the closed forest and forest-tundra have been present for at least similar to 240 yr. At all sites except the most southerly ones, past establishment is positively correlated with regional temperature increase. In the single-tree tundra, however, a change in growth form from krummholz to erect trees, beginning similar to 130 yr ago, rather than establishment date has been recorded. Seed mass decreases from south to north, while seed quantity increases. Simulations with LAVESI (Larix Vegetation Simulator) further suggest that relative density changes strongly in response to a warming signal in the forest-tundra while intra-specific competition limits densification in the closed forest and seed limitation hinders densification in the single-tree tundra. We find striking differences in strength and timing of responses to recent climate warming. While forest-tundra stands recently densified, recruitment is almost non-existent at the southern and northern end of the ecotone due to autecological processes. Palaeo-treelines may therefore be inappropriate to infer past temperature changes at a fine scale. Moreover, a lagged treeline response to past warming will, via feedback mechanisms, influence climate change in the future. KW - climate change KW - closed forest KW - dendroecology KW - forest change KW - latitude KW - recruitment KW - tundra KW - vegetation model Y1 - 2017 U6 - https://doi.org/10.1002/ecy.1887 SN - 0012-9658 SN - 1939-9170 VL - 98 SP - 2343 EP - 2355 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Wenz, Leonie A1 - Levermann, Anders A1 - Auffhammer, Maximilian T1 - North-south polarization of European electricity consumption under future warming JF - Proceedings of the National Academy of Sciences of the United States of America N2 - There is growing empirical evidence that anthropogenic climate change will substantially affect the electric sector. Impacts will stem both from the supply sidethrough the mitigation of greenhouse gasesand from the demand sidethrough adaptive responses to a changing environment. Here we provide evidence of a polarization of both peak load and overall electricity consumption under future warming for the worlds third-largest electricity marketthe 35 countries of Europe. We statistically estimate country-level doseresponse functions between daily peak/total electricity load and ambient temperature for the period 2006-2012. After removing the impact of nontemperature confounders and normalizing the residual load data for each country, we estimate a common doseresponse function, which we use to compute national electricity loads for temperatures that lie outside each countrys currently observed temperature range. To this end, we impose end-of-century climate on todays European economies following three different greenhouse-gas concentration trajectories, ranging from ambitious climate-change mitigationin line with the Paris agreementto unabated climate change. We find significant increases in average daily peak load and overall electricity consumption in southern and western Europe (similar to 3 to similar to 7% for Portugal and Spain) and significant decreases in northern Europe (similar to-6 to similar to-2% for Sweden and Norway). While the projected effect on European total consumption is nearly zero, the significant polarization and seasonal shifts in peak demand and consumption have important ramifications for the location of costly peak-generating capacity, transmission infrastructure, and the design of energy-efficiency policy and storage capacity. KW - electricity consumption KW - peak load KW - climate change KW - adaptation Y1 - 2017 U6 - https://doi.org/10.1073/pnas.1704339114 SN - 0027-8424 VL - 114 SP - E7910 EP - E7918 PB - National Acad. of Sciences CY - Washington ER -