Project

Clim4Vitis

Goal: Climate change impact mitigation for European viticulture: knowledge transfer for an integrated approach

Date: 1 September 2018 - 31 August 2021

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Chenyao Yang
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With global warming, grapevine is expected to be increasingly exposed to water deficits occurring at various development stages. In this study, we aimed to investigate the potential impacts of projected climate change on water deficits from the flowering to veraison period for two main white wine cultivars (Riesling and Müller-Thurgau) in Germany. A process-based soil-crop model adapted for grapevine was utilized to simulate the flowering-veraison crop water stress indicator (CWSI) of these two varieties between 1976–2005 (baseline) and 2041–2070 (future period) based on a suite of bias-adjusted regional climate model (RCM) simulations under RCP4.5 and RCP8.5. Our evaluation indicates that the model can capture the early-ripening (Müller-Thurgau) and late-ripening (Riesling) traits, with a mean bias of prediction of ≤2 days and a well-reproduced inter-annual variability for more than 60 years. Under climate projections, the flowering stage is advanced by 10–20 days (higher in RCP8.5) between the two varieties, whereas a slightly stronger advancement is found for Müller-Thurgau than for Riesling for the veraison stage. As a result, the flowering-veraison phenophase is mostly shortened for Müller-Thurgau, whereas it is extended by up to two weeks for Riesling in cool and high-elevation areas. The length of phenophase plays an important role in projected changes of flowering-veraison mean temperature and precipitation. The late-ripening trait of Riesling makes it more exposed to increased summer temperature (mainly in August), resulting in a higher mean temperature increase for Riesling (1.5–2.5 °C) than for Müller-Thurgau (1–2 °C). As a result, an overall increased CWSI by up to 15% (ensemble median) is obtained for both varieties, whereas the upper (95th) percentile of simulations shows a strong signal of increased water deficit by up to 30%, mostly in the current winegrowing regions. Intensified water deficit stress can represent a major threat for high-quality white wine production, as only mild water deficits are acceptable. Nevertheless, considerable variabilities of CWSI were discovered among RCMs, highlighting the importance of efforts towards reducing uncertainties in climate change impact assessment.
Daniel Molitor
added a research item
Für den Standort Remich liegen seit 1970 kontinuierliche, systematische Wetteraufzeichnungen der von der Administration des services techniques de l’agriculture (ASTA) betriebenen Wetterstation am Weinbauinstitut vor. Darüber hinaus berichtet seit mindestens 50 Jahren das jährlich erscheinende «Weinjahr» umfassende statistische Daten zum Luxemburger Weinbau hinsichtlich Rebphänologie, Erträgen, Erntemostgewichten und vielem mehr. Der Eintritt in die dritte Dekade des 21. Jahrhunderts bietet eine ideale Gelegenheit, sich die klimatischen Veränderungen der letzten fünf Jahrzehnte und deren Auswirkungen auf den Weinbau in Luxemburg genauer anzusehen. Die vorliegenden Auswertungen wurden im Rahmen der Forschungsprojekte „VinoManAOP“ und „Clim4Vitis“ durchgeführt.
João A Santos
added 8 research items
The assessment of aridity conditions is a key factor for water management and the implementation of mitigation and adaptation policies in agroforestry systems. Towards this aim, three aridity indices were computed for the Iberian Peninsula (IP): the De Martonne Index (DMI), the Pinna Combinative Index (PCI), and the Erinç Aridity Index (EAI). These three indices were first computed for the baseline period 1961‒1990, using gridded observational data (E-OBS), and subsequently, for the periods 2011‒2040 (short range) and 2041‒2070 (medium range), using an ensemble of six regional climate model (RCM) experiments generated by the EURO-CORDEX project. Two representative concentration pathways (RCPs) were analyzed, an intermediate anthropogenic radiative forcing scenario (RCP4.5) and a fossil-intensive emission scenario (RCP8.5). Overall, the three indices disclose a strengthening of aridity and dry conditions in central and southern Iberia until 2070, mainly under RCP8.5. Strong (weak) statistically significant correlations were found between these indices and the total mean precipitation (mean temperature) along with projected significant decreasing (increasing) trends for precipitation (temperature). The prevalence of years with arid conditions (above 70% for 2041‒2070 under both RCPs) are projected to have major impacts in some regions, such as southern Portugal, Extremadura, Castilla-La Mancha, Comunidad de Madrid, Andalucía, Región de Murcia, Comunidad Valenciana, and certain regions within the Aragón province. The projected increase in both the intensity and persistence of aridity conditions in a broader southern half of Iberia will exacerbate the exposure and vulnerability of this region to climate change, while the risk of multi-level desertification should be thoroughly integrated into regional and national water management and planning.
Land and climate are strongly connected through multiple interface processes and climate change may lead to significant changes in land use. In this study, high-resolution observational gridded datasets are used to assess modifications in the Köppen–Geiger and Worldwide Bioclimatic (WBCS) Classification Systems, from 1950–1979 to 1990–2019 in Portugal. A compound bioclimatic-shift exposure index (BSEI) is also defined to identify the most exposed regions to recent climatic changes. The temporal evolution of land cover with vineyards and olive groves between 1990 and 2018, as well as correlations with areas with bioclimatic shifts, are analyzed. Results show an increase of CSa Warm Mediterranean climate with hot summer of 18.1%, followed by a decrease in CSb (warm summer) climate of −17.8%. The WBCS Temperate areas also reveal a decrease of −5.11%. Arid and semi-arid ombrotypes areas increased, conversely humid to sub-humid ombrotypes decreased. Thermotypic horizons depict a shift towards warmer classes. BSEI highlights the most significant shifts in northwestern Portugal. Vineyards have been displaced towards regions that are either the coolest/humid, in the northwest, or the warmest/driest, in the south. For oliviculture, the general trend for a relative shift towards cool/humid areas suggests an attempt of the sector to adapt, despite the cover area growth in the south. As vineyards and olive groves in southern Portugal are commonly irrigated, options for the intensification of these crops in this region may threaten the already scarce water resources and challenge the future sustainability of these sectors.
Reliable estimations of parameter values and associated uncertainties are crucial for crop model applications in agro-environmental research. However, estimating many parameters simultaneously for different types of response variables is difficult. This becomes more complicated for grapevines with different phenotypes between varieties and training systems. Our study aims to evaluate how a standard least square approach can be used to calibrate a complex grapevine model for simulating both the phenology (flowering and harvest date) and yield of four different variety–training systems in the Douro Demarcated Region, northern Portugal. An objective function is defined to search for the best-fit parameters that result in the minimum value of the unweighted sum of the normalized Root Mean Squared Error (nRMSE) of the studied variables. Parameter uncertainties are estimated as how a given parameter value can determine the total prediction variability caused by variations in the other parameter combinations. The results indicate that the best-estimated parameters show a satisfactory predictive performance, with a mean bias of −2 to 4 days for phenology and −232 to 159 kg/ha for yield. The corresponding variance in the observed data was generally well reproduced, except for one occasion. These parameters are a good trade-off to achieve results close to the best possible fit of each response variable. No parameter combinations can achieve minimum errors simultaneously for phenology and yield, where the best fit to one variable can lead to a poor fit to another. The proposed parameter uncertainty analysis is particularly useful to select the best-fit parameter values when several choices with equal performance occur. A global sensitivity analysis is applied where the fruit-setting parameters are identified as key determinants for yield simulations. Overall, the approach (including uncertainty analysis) is relatively simple and straightforward without specific pre-conditions (e.g., model continuity), which can be easily applied for other models and crops. However, a challenge has been identified, which is associated with the appropriate assumption of the model errors, where a combination of various calibration approaches might be essential to have a more robust parameter estimation.
Daniel Molitor
added a research item
Der Klimawandel ist in Mitteleuropa längt angekommen ¬ mit bereits deutlich spürbaren Auswirkungen auf den Weinbau. Hinweise darauf, wie die Entwicklung weitergeht und worauf die Winzer sich einstellen müssen, können bereits jetzt messbare Trends geben. Dr. Daniel Molitor und Dr. Jürgen Junk vom Luxembourg Institute of Science and Technology (LIST) haben daher gemeinsam mit Mareike Schultz vom Institut Viti-vinicole in Remich (Luxemburg) vom Weinbauinstitut Remich systematisch aufgezeichnete Wetterdaten aus den letzten fünf Jahrzehnten analysiert und mit Blick auf den Weinbau in Luxemburg bewertet. Den ersten Teil ihrer Ergebnisse, der sicherlich auch als repräsentativ für die rheinland-pfälzischen Anbaugebiete angesehen werden kann, gibt der folgende Beitrag wieder.
Daniel Molitor
added a research item
Climate change is a major challenge to viticulture worldwide. The adaptation potential of the different strategies to cope with climate change still embraces many uncertainties (e.g., unpredictable social-economic developments and land-use changes), particularly in the long-term. However, adaptation strategies adjusted to local terroirs and regional climate change projections will contribute to the sustainable development of the winemaking sector. The Clim4Vitis action (https://clim4vitis.eu/) recommends some guidelines for long-term adaptation (Figure 1).
Daniel Molitor
added a research item
Viticulture is exposed and vulnerable to extreme weather and climate change. In Europe, owing to the high socio-economic value of the winemaking sector, the development of adaptation strategies to mitigate climate change impacts will be of foremost relevance for its future sustainability and competitiveness. Some guidelines on feasible short-term adaptation strategies are provided here (Figure 1), collected by the Clim4Vitis action (https://clim4vitis.eu/). Long-term adapation startegies are described in an accompanying technical review.
Helder Fraga
added a research item
Extreme heat events or heatwaves can be particularly harmful to grapevines, posing a major challenge to winegrowers in Europe. The present study is focused on the application of the crop model STICS to assess the potential impacts of heatwaves over some of the most renowned winemaking regions in Europe. For this purpose, STICS was applied to grapevines, using high-resolution weather, soil and terrain datasets from 1986 to 2015. To assess the impact of heatwaves, the weather dataset was artificially modified, generating periods with anomalously high temperatures (+5 °C), at specific onset dates and with specific episode durations (from five to nine days). The model was then run with this modified weather dataset, and the results were compared to the original unmodified runs. The results show that heatwaves can have a very strong impact on grapevine yields. However, these impacts strongly depend on the onset dates and duration of the heatwaves. The highest negative impacts may result in a decrease in the yield by up to −35% in some regions. The results show that regions with a peak vulnerability on 1 August will be more negatively impacted than other regions. Furthermore, the geographical representation of yield reduction hints at a latitudinal gradient in the heatwave impact, indicating stronger reductions in the cooler regions of Central Europe than in the warmer regions of Southern Europe. Despite some uncertainties inherent to the current modelling assessment, the present study highlights the negative impacts of heatwaves on viticultural yields in Europe, which is critical information for stakeholders within the winemaking sector for planning suitable adaptation measures.
Daniel Molitor
added 2 research items
The aim of the present investigations was to simulate the annual risk of bunch rot (Botrytis cinerea) on Vitis vinifera L. cv. Riesling grapes based on three long-term (n = 3 × 7 = 21 cases) assessment data sets originating from three Central European grape-growing regions. Periods when meteorological parameters were significantly (p < 0.01) correlated with the cumulative degree day (CDD7;18;24) reaching 5% disease severity were determined by Window Pane analysis. Analyses revealed five critical weather constellations (“events”) influencing annual epidemics: relatively low temperatures after bud break, dry conditions during flowering, high temperatures after flowering, and low temperatures and high precipitation sums during/after veraison were all associated with thermal-temporal early epidemics. Meteorological data in each of the five events served as input for the bunch rot risk model “BotRisk.” The multiple linear regression model resulted in an adjusted coefficient of determination (R2adj.) of 0.63. BotRisk enables (i) the simulation of the thermal-temporal position of the annual epidemic and, based on this, (ii) the classification of the annual bunch rot risk into three classes: low, medium, or high risk. According to leave-one-out cross-validation, 11 of 21 case studies were correctly classified. No systematic bias caused by location was observed, indicating that the transfer of the model into other locations with comparable climatic conditions could be possible. BotRisk (i) represents a novel viticultural decision support tool for crop cultural and chemical measures against bunch rot and (ii) enables an estimation of the bunch rot risk under changing environmental conditions.
Present investigations aimed at developing a unified cumulative degree day based model approach allowing for (i) a precise simulation of grapevine phenological development of a broad range of cultivars and (ii) a classification of the cultivar specific relative precocity of different cultivars at different stages of grape development. Based on a long-term (7-year) data set of high-resolution phenological observations for 11 cool climate cultivars originating from Remich/Luxembourg, the unified phenological model (UniPhen) was developed using a cumulative degree day approach with three temperature thresholds (lower threshold: 10 °C; upper threshold: 20 °C; heat threshold: 30 °C). The average normalized standard deviation of UniPhen over all stages and cultivars was 5.26 corresponding to 5.26 days at 15 °C. In the cross-validated model, on average 53% of the observations were located in a range of ± 3 days and 82% in a range of ±7 days (assuming daily mean temperatures of 15 °C) around the predicted date. The sequence of the cultivar-specific relative precocity was not stable over the different stages of phenological development. The model approach (i) enables a precise simulation of all 31 BBCH stages between beginning of the bud swell (01) and berries being ripe for harvest (89) for 11 cultivars grown in the climatic conditions of the Luxembourgish grapegrowing region and (ii) is open to being extended to other grape cultivars and re-calibrated under deviant climatic conditions. Due to their instability, a classification of the cultivars’ relative precocity is only reasonable if it relates to a specific phenological stage. UniPhen represents a precise high-resolution phenological model approach and might be applied as a bioclimatic indicator describing the suitability of a location/region for the cultivation of specific cultivars.
Daniel Molitor
added a research item
Budbreak date in grapevine is strictly dependent on temperature, and the correct simulation of its occurrence is of great interest since it may have major consequences on the final yield and quality. In this study, we evaluated the reliability for budbreak simulation of two modeling approaches, the chilling-forcing (CF), which describes the entire dormancy period (endo- and eco-dormancy) and the forcing approach (F), which only describes the eco-dormancy. For this, we selected six phenological models that apply CF and F in different ways, which were tested on budbreak simulation of eight grapevine varieties cultivated at different latitudes in Europe. Although none of the compared models showed a clear supremacy over the others, models based on CF showed a generally higher estimation accuracy than F where fixed starting dates were adopted. In the latter models, the accurate simulation of budbreak was dependent on the selection of the starting date for forcing accumulation that changes according to the latitude, whereas CF models were independent. Indeed, distinct thermal requirements were found for the grapevine varieties cultivated in Northern and Southern Europe. This implies the need to improve modeling of the dormancy period to avoid under- or over-estimations of budbreak date under different environmental conditions.
João A Santos
added a research item
Viticulture and winemaking are important socioeconomic sectors in many European regions. Climate plays a vital role in the terroir of a given wine region, as it strongly controls canopy microclimate, vine growth, vine physiology, yield, and berry composition, which together determine wine attributes and typicity. New challenges are, however, predicted to arise from climate change, as grapevine cultivation is deeply dependent on weather and climate conditions. Changes in viticultural suitability over the last decades, for viticulture in general or the use of specific varieties, have already been reported for many wine regions. Despite spatially heterogeneous impacts, climate change is anticipated to exacerbate these recent trends on suitability for wine production. These shifts may reshape the geographical distribution of wine regions, while wine typicity may also be threatened in most cases. Changing climates will thereby urge for the implementation of timely, suitable, and cost-effective adaptation strategies, which should also be thoroughly planned and tuned to local conditions for an effective risk reduction. Although the potential of the different adaptation options is not yet fully investigated, deserving further research activities, their adoption will be of utmost relevance to maintain the socioeconomic and environmental sustainability of the highly valued viticulture and winemaking sector in Europe.
Daniel Molitor
added a research item
Gemäß vorliegender Analysen wird unter den Bedingungen des luxemburgischen Moseltals jede einzelne der 27 phänologischen Entwicklungsstadien nach BBCHCode in der Zukunft früher im Jahr eintreten als in der Vergangenheit. Während signifikante Änderungen in der Länge der Phänophasen in den frühen Entwicklungsstadien absent sind, verkürzt sich nach vorliegenden Projektionen die Länge der Reifephase signifikant. Aufgrund des projizierten generellen Temperaturanstieges und des Verschiebens des Zeitraums der Reifephase in Richtung einer früheren (und damit in der Regel wärmeren) Phase des Jahres, impliziert der Klimawandel einen zweifachen Anstieg der Temperaturen in der Reifephase. Als Konsequenz ist der zu erwartende Anstieg der Temperaturen in der Reifephase („Ferne Zukunft“ im Vergleich zur Referenzperiode in der Rebsorte Riesling: + 5.1 °C) deutlich stärker ausgeprägt als im Jahresmittel (+ 2.6 °C). Dieser signifikante Anstieg der Reife-Temperaturen lässt eine Veränderung der Weintypizität der traditionellen Weinbauregionen erwarten und erfordert voraussichtlich spezifische Anpassungsmaßnahmen.
Daniel Molitor
added a research item
Dr. Daniel Molitor und Dr. Jürgen Junk, LIST – Luxembourg Institute of Science and Technology, nehmen in den folgenden Ausführungen Stellung zu den Herausforderungen, die bedingt durch den Klimawandel für die Eisweinerzeugung entstanden sind.
Marco Beyer
added a research item
The drosophilid fly Drosophila suzukii is an invasive pest that has recently started threatening fruit production in Europe. In contrast to many other fruit flies, D. suzukii is able to lay eggs in ripening and mature fruits where larvae develop, rendering fruits unmarketable. This preference for ripening fruit requires pest control shortly before harvest, implying a high risk of residues on the fruit if synthetic insecticides are used. As the current management practices largely rely on chemical control, the need for alternative solutions has emerged. Here, we review the studies published up to now on the efficacy of natural compounds against D. suzukii. Several natural compounds were identified that act as repellents, contact or ingestion toxicants, fumigants, ovicides or oviposition deterrents. The most promising compounds of each group were (i) essential oils (EOs) such as the EO of thyme or its major ingredient thymol which repelled flies from fresh fruits for at least 24 h; (ii) Leptospermum ericoides and L. scoparium EOs, which expressed contact toxicity at a LD50 < 1.2 μg/fly; (iii) the combination of erythritol and sucrose, which was a potent ingestion toxicant against adults and (iv) a chitinase from Euphorbia characias against larvae (both of the latter two resulted in 100% mortality); (v) the EO ingredients perilla aldehyde, geranial and neral showed the highest insecticidal activities as fumigants (LC50 < 1.52 mg/l air for males and 2.6 mg/l air for females) and (vi) powdered sulphur was reported to be the most efficient oviposition deterrent, reducing the number of eggs deposited into the fruits by 76%. To enable a wider use of the natural compounds in sustainable agriculture, more information on (i) potential effects on non-target organisms, (ii) field performance and (iii) life cycle analyses results is currently needed.
João A Santos
added a research item
Thermal conditions in mainland Portugal were evaluated using a new hourly database over the recent period of 2000-2018 (19 years). The number of hours within each different temperature interval was calculated from the long-term means of the hourly temperatures of a network of 63 meteorological stations. A geostatistical approach, using elevation, distance to coastline and latitude, was subsequently applied to provide gridded patterns at a high spatial resolution (1 km grid spacing). Eight fruit species (almond tree, carob tree, chestnut tree, citrus fruits, cork oaks, holm oaks, olive trees, and grapevines) were selected to assess their hourly thermal growing conditions. The results highlight the strong spatial variability of temperature levels in mainland Portugal, providing new insights into their spatial distribution. The number of hours in the year with cool conditions (4-12 • C) is higher in the northern-central regions, mainly in mountainous areas. Additionally, the number of hours in the year with temperate conditions (12-20 • C) emphasizes the importance of the distance to the coastline (maritime influence). The warm conditions (20-28 • C) are most prevalent in the south of the country and in the Douro valley, whereas the very warm conditions (number of hours with temperature between 28-36 • C) are essentially restricted to inner-southern Portugal and to the upper Douro valley. This study also reveals, with high accuracy, the thermal growing conditions of main fruit species in mainland Portugal, giving particular emphasis to olive trees and grapevines. These findings may help decision support systems providing more reliable and accurate guidelines to stakeholders, decision-makers, and farmers. The main maps are available in a widely used file format (shapefile), thus allowing their application to a wide range of other areas of interest.
Daniel Molitor
added a research item
Aim: Grape (Vitis vinifera L.) phenology is mainly temperature-driven. Consequently, the shift in thermal conditions due to climate change is supposed to have a distinct influence on grape phenology, grape maturity and wine typicity. This study aims to investigate (i) the future phenological development, as well as (ii) the consequences on the temperature conditions in specific phenophases under the conditions of the Luxembourg grapegrowing region. Methods and Results: A budburst model and a phenological model were combined with an ensemble of ten regional climate change projections for Luxembourg. Analyses comparing four 30-year time spans (reference period: 1971-2000; present: 2001-2030; near future: 2031-2060; far future: 2061-2090) demonstrated that each of the 27 phenological stages according to BBCH code is projected to be reached significantly earlier than in the reference period. According to these projections, the length of phenophases at the early stages is not affected, whereas the ripening period length is significantly shortened. The air temperature increase in the ripening period (far future compared to reference period: + 4.6 °C to + 5.3 °C) is projected to be markedly higher than in the annual averages (+ 2.6 °C). Conclusions: Since (i) air temperatures are generally projected to increase in the future and (ii) the ripening period will take place earlier (usually in the warmer parts of the season), climate change is implicating a two-fold impact on air temperature increase in the ripening period. Significance and impact of the study: This two-fold impact potentially threatens the wine typicity of the traditional grapegrowing regions and therefore calls for specific adaptation strategies.
Daniel Molitor
added a research item
The low-input viticultural training system ‘Semi-minimal pruned hedge’ (SMPH) is progressively being more widely applied in the Central European grapegrowing regions. The present study examined the influence of (i) the training system (SMPH versus the vertical shoot position (VSP) system), (ii) the timing of shoot topping in SMPH, and (iii) the effects of mechanical thinning in SMPH on the bunch rot epidemic, grape maturity, and yield. Six-year field trials on Pinot blanc in Luxembourg demonstrated that yield levels in non-thinned SMPH treatments were 74% higher, and total soluble solids (TSS) at harvest 2.2 brix lower than in VSP. Non-thinned SMPH delayed the bunch rot epidemic and the maturity progress by 18 and 11 days compared to VSP, respectively. Different shoot-topping timings in SMPH did not affect the tested parameters. Mechanical thinning regimes reduced the yield by 28% (moderate thinning) and 53% (severe thinning) compared to non-thinned SMPH and increased TSS by 0.8 and 1.3 brix, respectively. Delayed bunch rot epidemic and maturity progress give rise to the opportunity for a longer maturity period in cooler conditions, making this system of particular interest in future, warmer climatic conditions. Providing that yield levels are managed properly, SMPH might represent an interesting climate change adaptation strategy.
João A Santos
added an update
João A Santos
added a project goal
Climate change impact mitigation for European viticulture: knowledge transfer for an integrated approach