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Yield forecasts are generally based on a combination of expert knowledge, survey data, statistical analyses and model simulations. These forecasts, when public, influence crop prices and can be used to estimate end-of-season stocks. Thus, the skills and limitations of such products are important because they inform trade policies. In Europe, yield forecasts are made available to stakeholders throughout the growing season via the monthly MARS (Monitoring Agricultural ResourceS) Bulletin. The MARS Crop Yield Forecasting System relies on an in-depth analysis of past climate, short-term weather forecasts and crop growth simulations. In this paper, we focus on the occurrence of abnormally low yields and evaluate how accurately agro-climatic indicators and model outputs anticipate their occurrences for two crop species in two European countries of contrasted agroclimatic conditions. Importantly, the indicators considered here encompass a large range of complexity levels and several are used to inform the yield forecasts presented in the MARS Bulletin. Each indicator is independently used to predict the onset occurrence of an abnormal yield loss (henceforth named extreme) in France and in Spain for both winter wheat and non-irrigated grain maize for a period covering the 1976–2013 growing seasons. Indicators are ranked based on a score quantifying their ability to accurately separate extreme from non-extreme yield loss events. We provide and in-depth analysis of the robustness of our ranking to alternative definitions of extreme yield loss. No single indicator performs systematically well (e.g., whatever the country or crop species) but several show acceptable scores (e.g., averaged temperatures, vapor pressure deficit, precipitation, potential yield). We find no obvious relationship between the level of complexity of indicators and their accuracy. Single climate variables such as temperature or precipitation often perform as well as a crop model integrating temperatures and precipitation effects on crop growth. Namely, monthly averaged maximum temperatures and precipitation rank highest for both crop species in France. Drought indices perform well in Spain for wheat and for maize. We argue that our transparent framework can be useful to evaluate and improve crop-monitoring systems worldwide. [ABSTRACT FROM AUTHOR]

• Risk assessment of intensity & duration of cold episodes in vineyards. • Cold monitoring strategies in vineyards using robust multivariate approach. • Improving frost risk modelling using copula model. • Prediction of frost events return period with copula model. Frost, particularly during the spring, is one of the most damaging weather phenomena for vineyards, causing significant economic losses to vineyards around the world each year. The risk of tardive frost damage in vineyards due to changing climate is considered as an important threat to the sustainable production of grapes. Therefore, the cold monitoring strategies is one of the criteria with significant impacts on the yields and prosperity of horticulture and raisin factories. Frost events can be characterized by duration and severity. This paper investigates the risk and impacts of frost phenomenon in the vineyards by modeling the joint distribution of duration and severity factors and analyzing the influential parameter's dependency structure using capabilities of copula functions. A novel mathematical framework is developed within this study to understand the risk and uncertainties associate with frost events and the impacts on yields of vineyards by analyzing the non-linear dependency structure using copula functions as an efficient tool. The developed model was successfully validated for the case study of vineyard in Malayer city of Iran. The copula model developed in this study was shown to be a robust tool for predicting the return period of the frost events. [ABSTRACT FROM AUTHOR]

Spatial distribution of decadal average SPEI in the 2030s, 2050s, and 2080s in (a) RCP 2.6 Scenario; (b) RCP 4.5 Scenario; (c)RCP 8.5 Scenario. • Climate change would affect the extent and global distribution of drought. • Global drought would be more aggravated in RCP 8.5 scenario. • Significant increase of ET 0 would occur in most grain producing countries. Drought is the most widespread and most influential natural disaster in the world, especially a threat to agricultural production. In future climate scenarios, the meteorological elements such as precipitation and temperature in each region will change, which will affect the distribution and characteristics of global drought in the future. In this paper, the global drought propensity was evaluated by reformulated Standardized Precipitation Evapotranspiration Index (SPEI-PM) based on Penman-Monteith equation in three future climate scenarios (RCP2.6, RCP4.5 and RCP8.5) of 9 General Circulation Models (GCMs). Mann-Kendall (MK) trend test and empirical orthogonal function (EOF) analysis were used to assess the spatial-temporal distribution and evolution characteristics of the future global drought. Taking reference evapotranspiration (ET 0) of crops as the index, potential effects of global drought on agricultural water use were assessed. The results showed that under the influence of the changes of future temperature, precipitation and other meteorological factors, the global drought has presented regional difference characteristics. In three climate scenarios, the trend of severe drought was detected in Africa, North America, South America and Oceania in three climate scenarios. Spatial distribution of SPEI is consistent and intensified drought was detected in southern, northern and northeast of Africa in three decades in all scenarios. EOF analysis showed that there were more positive time coefficients in RCP8.5 scenario than other scenarios, then parts of South America and Africa would face intensified drought in all climate scenarios. The evolution of future global drought would pose a threat on global water use for agricultural production. The annual average ET 0 of three decades in major grain producing countries would be on the rise compared to the baseline (1976–2005), among which RCP8.5 scenario was most obvious. Large increase rate of ET 0 would occur in Ukraine, Turkey, Russia and Canada in the 2080s in three scenarios. In the future, major grain producing countries would face serious threats of drought, which would pose a great challenge to regional agricultural water use. The study will provide forward-looking information to alleviate the adverse effects of drought on agricultural water use. [ABSTRACT FROM AUTHOR]

• Phytophthora cinnamomi and soil moisture affected Quercus suber performance. • The inoculum density required to cause disease increased at lower soil moisture. • An average drier climate might imply a slower advance of the disease. • On the contrary, more frequent extreme rain events might favor the disease. Climate change and exotic pests and pathogens are causing alarming forest declines worldwide. However, we still lack a comprehensive understanding of how damage caused by exotic pests and pathogens might vary under the different scenarios of water availability imposed by a changing climate, particularly in water-limited forests as those that occupy Mediterranean areas. In this paper we aimed to experimentally analyse the interactive effects of the aggressive exotic pathogen Phytophthora cinnamomi and climate change-related reductions in soil moisture on seedling performance of the Mediterranean host Quercus suber. We conducted a full-factorial greenhouse experiment where the physiology and growth of Q. suber seedlings was measured in soils with different combinations of P. cinnamomi inoculum density (0, 30, 60 and 120 colony forming units per gram of dry soil) and soil moisture (15%, 40%, 50% and 100% soil water holding capacity) simulating different invasion and climate change scenarios. We found additive effects of P. cinnamomi and drought on Q. suber performance aboveground, although these effects were not always negative. In fact, seedlings showed a compensatory physiological response to P. cinnamomi infection by increasing their net photosynthetic rates. Our results also supported important interactive effects of pathogens and soil moisture on belowground performance. Thus, the inoculum density in the soil required to cause significant root damage in experimental seedlings decreased as soil moisture increased. From a climate change perspective, these results suggest that an average drier climate might imply sub-optimal conditions for P. cinnamomi infections allowing for a slower advance of the disease in invaded areas. However, this effect will be modulated by the also predicted more frequent extreme climatic events. A higher frequency of extreme rain events that saturate the soil might be particularly beneficial for P. cinnamomi , boosting its soil density beyond any possible response capacity of susceptible hosts. [ABSTRACT FROM AUTHOR]