Past, present and future distributions of Oriental beech (Fagus orientalis) under climate change projections

potential late Quaternary refugia of F. orientalis, (iii) to investigate the late Quaternary history of Fagus based on published palynological data, and finally, (iv) to project the future distribu- tion of F. orientalis under different climate change scenarios. Materials and methods Study region and occurrence data The study region (22˚–54˚ E 35˚–47˚ N) is defined by the observed distribution range of F. orientalis with some extensions for possible future or past range expansions. Occurrence data were obtained from forest management plans of the General Directorate of Forestry of Turkey (GDF) for the distribution of the species in Turkey and the European Forest Genetic Resources Program (F. orientalis–EUFORGEN [38]) for the remaining areas. We merged these two layers of data in ArcGIS (version 10.3.1) and created a single, presence-only dataset (Fig 1) to be used in the models. All occurrence points, obtained from EUFORGEN and GDF, were transformed into 2.5’ spatial resolution using ArcGIS, generating 10,493 presence points for 457,681 raster cells across the study area. Environmental parameters Since the climate is the main abiotic factor shaping species distribution [24], we used nine of 19 bioclimatic variables obtained from WorldClim version 1.4 [39] as the main environmental Fig 1. Modern range of F. orientalis based on occurrence data from EUFORGEN (red) and General Directorate of Forestry of Turkey (green). https://doi.org/10.1371/journal.pone.0242280.g001 PLOS ONE Species distribution modeling of Oriental beech (Fagus orientalis)

PLOS ONE | https://doi.org/10.1371/journal.pone.0242280 November 17, 2020 3 / 19