Geo&Bio (Jun 2023)
Climatic limits for the present European distribution of the common hornbeam (Carpinus betulus), with special reference to Ukraine
Abstract
In this study, we used a comprehensive approach to detect the importance of diverse climatic parameters in controling the distribution of a forest tree species, exemplified by the common hornbeam (Carpinus betulus L.). Special reference has been made to Ukraine from where digitized data on the species is relatively scarce. In Ukraine, populations of the common hornbeam are found at the edge of its geographic range, primarily in forest-steppe ecotones, which are exposed to extreme climate with water shortages during the growing season and low temperatures in winter. Usually forests in these ecotones are highly fragmented and, in addition to climate impact, are heavily subjected to land use. Currently, in the east of the country, C. betulus is only very locally distributed, but it has been assumed that in the past there were several areas suitable for the persistence of the species. The main objectives of the present study were to model the European-wide ecological niche of the common hornbeam and investigate primary climatic factors that control the potential distribution of this tree in Ukraine. Using an ecological niche modelling approach, we consider to have reliably modeled the European-wide bioclimatic niche of the common hornbeam for predicting the response of species’ geographical distribution to climate. Most contributing to the model were the mean monthly PET (potential evapotranspiration) of the coldest quarter, continentality, and annual PET. In terms of the ‘Most Limiting Factor,’ in Ukraine, continentality is crucial throughout the majority of the country (78%). Because the distribution of any species depends on variables related to climate, it is likely that the species could rapidly respond to climatic change. In this respect, the common hornbeam is no exception, as exemplified by the history of the species in Eastern Europe. Limiting factors and thresholds (particularly of PET indices) are bound to shift together with global climate change and bring in changes to the pattern of the common hornbeam distribution, especially at edges of its geographic range.
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