Abstract:

We use the Worldwide Bioclimatic Classification system to identify changes in the bioclimatic characteristics of Greece between the present and the recent past, by comparing two reference periods: 1961-1990 and 1991-2020. This classification system, developed by Rivas-Martínez et al. (2011), defines the relationship between climatic variables, expressed through bioclimatic indices, and the corresponding distribution of natural vegetation. It generates distinct climatic units known as isobioclimates, which represent specific combinations of macrobioclimates, thermotypes, and ombrotypes. These isobioclimates link climate to ecosystems and allow the characterization of environmental diversity across spatial and temporal scales. The climate input for the system consists of mean, maximum, and minimum monthly temperatures and accumulated monthly precipitation. For this study, we use the ERA5-Land monthly mean data sets from the Copernicus Climate Data Store (CDS), averaged over the two study periods. Calculation of bioclimatic indices and mapping of the isobioclimates are performed using ArcGIS. Preliminary results indicate a shift in the isobioclimatic structure of Greece towards warmer thermotypes and drier ombrotypes. These changes are mostly evident in southern and lowland regions and may reflect increasing aridity and temperatures, suggesting an intensification of ecological stress and wildfire risk, with potential consequences for biodiversity. This work will be extended with the use of regional climate model projections to explore possible future bioclimatic changes in Greece, that will help to assess how climate change may affect vegetation types and inform strategies for ecosystem management in the coming decades.

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