• Energy Research

Climate change is affecting the distribution of pathogens and their arthropod vectors worldwide, particularly at northern latitudes. The distribution of Culicoides sonorensis (Diptera: Ceratopogonidae) plays a key role in affecting the emergence and spread of significant vector borne diseases such as Bluetongue (BT) and Epizootic Hemorrhagic Disease (EHD) at the border between USA and Canada. We used 50 presence points for C. sonorensis collected in Montana (USA) and south-central Alberta (Canada) between 2002 and 2012, together with monthly climatic and environmental predictors to develop a series of alternative maximum entropy distribution models. The best distribution model under current climatic conditions was selected through the Akaike Information Criterion, and included four predictors: Vapour Pressure Deficit of July, standard deviation of Elevation, Land Cover and mean Precipitation of May. This model was then projected into three climate change scenarios adopted by the IPCC in its 5th assessment report and defined as Representative Concentration Pathways (RCP) 2.6, 4.5 and 8.5. Climate change data for each predictor and each RCP were calculated for two time points pooling decadal data around each one of them: 2030 (2021-2040) and 2050 (2041-2060). Our projections showed that the areas predicted to be at moderate-high probability of C. sonorensis occurrence would increase from the baseline scenario to 2030 and from 2030 to 2050 for each RCP. The projection also indicated that the current northern limit of C. sonorensis distribution is expected to move northwards to above 53°N. This may indicate an increased risk of Culicoides-borne diseases occurrence over the next decades, particularly at the USA-Canada border, as a result of changes which favor C. sonorensis presence when associated to other factors (i.e. host and pathogen factors). Recent observations of EHD outbreaks in northern Montana and southern Alberta supported our projections and considerations. The results of this study can inform the development of cost effective surveillance programs, targeting areas within the predicted limits of C. sonorensis geographical occurrence under current and future climatic conditions.

AbstractGlobal change is expected to have complex effects on the distribution and transmission patterns of zoonotic parasites. Modelling habitat suitability for parasites with complex life cycles is essential to further our understanding of how disease systems respond to environmental changes, and to make spatial predictions of their future distributions. However, the limited availability of high quality occurrence data with high spatial resolution often constrains these investigations. Using 449 reliable occurrence records for Echinococcus multilocularis from across Europe published over the last 35 years, we modelled habitat suitability for this parasite, the aetiological agent of alveolar echinococcosis, in order to describe its environmental niche, predict its current and future distribution under three global change scenarios, and quantify the probability of occurrence for each European country. Using a machine learning approach, we developed large‐scale (25 × 25 km) species distribution models based on seven sets of predictors, each set representing a distinct biological hypothesis supported by current knowledge of the autecology of the parasite. The best‐supported hypothesis included climatic, orographic and land‐use/land‐cover variables such as the temperature of the coldest quarter, forest cover, urban cover and the precipitation seasonality. Future projections suggested the appearance of highly suitable areas for E. multilocularis towards northern latitudes and in the whole Alpine region under all scenarios, while decreases in habitat suitability were predicted for central Europe. Our spatially explicit predictions of habitat suitability shed light on the complex responses of parasites to ongoing global changes.

Since the 1990s, Common Cranes migrating in autumn through Italy have increased significantly both in number and in flock size. In the present study we provided a countrywide profile of autumn crane migration across Italy between 2001 and 2007 (486 records). To investigate the association of climatic characteristics with temporal and spatial migration patterns, we used weather data and climate anomalies over 60 years (1948-2007; NCEP/NCAR Reanalysis Project database). Autumn migration showed different phenological patterns along two main migratory routes: 1) a Southern Italy route and 2) a Northern Italy route. The Southern route, across the lower Adriatic Sea was only partially described before, and more inferred than documented, whereas the Northern route, across the Po River plain, resulted as a new flyway, never described before. Crane migrations along the Northern route occurred 7 to 14 days earlier than along the Southern one. Along both routes, we detected mass migration events concurring with particular weather conditions: the use of Southern route was associated with southward winds in the Balkans, the records along Northern route with high pressure and favourable westward winds in Central Europe and in the main stop-over site (Hortobagy) of likely origin. In the last 60 years, the occurrence of the latter weather configurations has slightly, but consistently, increased, suggesting that the Northern route may have recently established as an alternative route for the cranes migrating from Eastern Europe, joining the two traditional continental routes (the West-European, and the Baltic-Hungarian).