Modelling the distribution of the Caucasian oak (Quercus macranthera) in Western Asia under future climate change scenarios

Abstract

The Caucasian oak (Quercus macranthera), a native tree of Western Asia, typically grows at high altitudes where the effects of climate change are particularly notable. We analysed the climatic determinants of the current distribution of Q. macranthera and assessed the redistribution of areas suitable for this species as a consequence of climate change. We described the current range of distribution and predicted the potential geographical distribution of the Caucasian oak using species distribution models and five algorithms from two Shared Socio-Economic Pathways (SSPs: SSP 1-2.6 and 5-8.5) for the years 2035, 2055, and 2085, which are based on two General Circulation Models (GCMs). The Random Forest algorithm most accurately described the current distribution of Q. macranthera. SSP 1-2.6 and SSP5-8.5 predicted a pronounced contraction of the highly suitable habitat for the Caucasian oak due to the increase in temperatures and changes in seasonal precipitation dynamics, that more intensive climate change could lead to a greater loss of highly suitable habitats, and that the populations of Q. macranthera could survive only in the Alborz Mountains (northern Iran) and in the Great Caucasus Mountains. Our work helps to establish conservation strategies for species monitoring in order to minimise the potential impacts of climate change.