Global warming impact on floral phenology of fruit trees species in Mediterranean region

IUMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitières

إنجليزي. This study was carried out in three geographically contrasting countries of the Mediterranean region. Itaims to understand the impact of climate change, particularly the temperature increases, on phenologicalstage of three taxonomically different species (early and late-spring-flowering species). Three species,namely olive (Olea europaea), apple (Malus domestica Borkh.) and almond (Prunus dulcis (Mill.)) wereinvestigated to highlight the phenological behavior of one species at different locations and differentspecies at one location. Climatic and phenological data were collected from Morocco, France and Italyover the last 40 years. Analysis of data on temperature showed a strong warming in the northern locations(coldest areas), particularly in Nîmes, compared to the southern ones (warmer locations) during theperiod October to May. The marked spring warming in all locations since the end of 1980s in France(the beginning of 1990s in Italy and Morocco) resulted in blooming earliness, with regional patterns interms of impact. The late-spring-flowering species (olive and apple) showed a remarkable sensitivity tocontinuous warming in different areas. No flowering earliness was observed in early-spring-floweringspecies (almond), due to the stability of mean temperature during February. Thus, a strong control ofmean temperature during the forcing period on flowering earliness of apple was found in all areas.Physiological processes (dormancy and dormancy release) of trees during the dormant and growth periodexplain, in part, the regional differences observed in flowering dates among sites and species. Overall, thepronounced warming in the southern France reflects a relative trend toward aridity of climate at this site,and consequently some vulnerability of fruit trees. As result, the process of flowering in a high latitudelocations (northern areas) in the future can be represented by that in a low latitude locations at present(southern areas), particularly for apple.