Anadolu’da Konifer Ağaçların Yayılış Alanlarındaki Değişimler

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. ABSTRACT Climate change is recognized as a major threat to the survival of species and the integrity of ecosystems. Changes in climate have had substantial effects on the floristic density, presence of relict species, and endemism of certain regions. Anatolia has been one of the shelter areas for plants in the eastern Mediterranean Basin, particularly during the climate changes in the Quaternary. Several tree species expanded their distribution areas toward Anatolia in the Mediterranean Basin during the Last Glacial Maximum (LGM). However, during the 21 st century, rising temperatures in the eastern Mediterranean Basin are likely to impact the distribution of conifer trees. According to the International Union for Conservation of Nature (IUCN) Red Endangered Species, Cedrus libani and Abies cilicica subsp. isaurica are classified as “Vulnerable (VU),” while Abies cilicica subsp. cilicica is classified as “Near Threatened (NT).” Also, Juniperus drupacea is a Tertiary relict plant and has narrow distribution. In addition, human activities are among the primary factors limiting the distribution of the species. Therefore, we aim to determine the possible distribution status of Cedrus libani, Abies cilicica , and Juniperus drupacea in Anatolia during the LGM and in the future, taking into account various climate change scenarios, while excluding the effects of humans. In this study, fossil pollen records of Cedrus, Abies , and Juniperus were used to test the performance of LGM models and identify potential past refuges. The occurrence distribution data of the species were retrieved from the Global Biodiversity Information Facility (GBIF) database, European Forest Genetic Resources Programme (EUFORGEN) database, and field studies. A total of 19 bioclimatic variables were obtained from WorldClim to create models of species distribution. Principal component analysis (PCA) was applied to these variables, resulting in the identification of 8 variables for the Species Distribution Model. As climate input, CCSM4 (Community Climate System Model, version 4) climate projections under The representative concentration pathway (RCP) 8.5 scenario were used. Bioclimatic variables data included LGM, present, and future data from CCSM4’s