Changes in the Distribution Areas of Conifer Trees in Anatolia

Abstract

This study aims to estimate the responses of Cedrus libani, Abies cilicica, and Juniperus drupacea to the Last Glacial Maximum (LGM), present and future climate changes in Anatolia. For this purpose, the temporal and spatial distributions of these conifer species were modeled, based on global climate change scenarios. Accordingly, the temporal and spatial distributions of the studied species are predicted and back-projected using fossil pollen data, occurrence data, and 19 bioclimatic variables collected from the WorldClim database. The principal component analysis (PCA) method was applied to these variables, resulting in the identification of 8 variables for the species distribution model. Past and future climate information is based on CCSM4 and RCP 8.5 scenario was assumed for future projections. Furthermore, both MaxEnt 3.4.1 and ArcGIS 10.5 were utilized to develop the models. At every instance, the area under curve (AUC) test values that determine the accuracy of the projections is >0,90. Among the 8 bioclimatic variables, those that contributed the most to the models were as follows: Cedrus libani, BIO14 (%32,3), BIO8 (%23,7), BIO15 (%19,2);Abies cilicica BIO8 (%30,5), BIO14 (%24,1), BIO15 (%19,5); Juniperus drupacea, BIO15 (%38,1), BIO12 (%30,9), and BIO4 (%13,1). Cedrus libani, Abies cilicica, and Juniperus drupacea found suitable habitats in the south of Anatolia during the LGM, according to the results. From the Holocene onward, their distribution areas narrowed and reached the present-day borders. Future predictions indicate that some of the ecological conditions of the species will be lost, and their areas will narrow.