Climatic drivers of ecological divergence among the genera of the tribe Stipeae in Turkey

Abstract

The species from the tribe Stipeae Dumort. dominate Eurasian grasslands including Anatolian steppes. In Turkey, the genera of the Stipeae show distinct patterns of regional distribution, leading to a combination of dispersal and adaptive radiation. However, the importance of climatic gradients to regional distribution of these genera of the Stipeae has not yet been examined, and the aim of our study was to address this need. We retrieved data on the presence of three genera of the Stipeae, and morphological traits of its member species in Anatolia from available literature. We also acquired data on bioclimatic variables from the WorldClim database. We used multivariate methods (PCA) and correlation analysis to describe the major climatic gradients within the distribution area of the Stipeae in Anatolia. Links between the major climatic gradients and the divergence of the genera were examined using the method of Spatial Evolutionary and Ecological Vicariance Analysis (SEEVA). Possible relationships between the genera of the Stipeae and climatic and geographic variables were also examined by means of Canonical Correspondence Analysis (CCA). Our results suggest that elevation and temperature are the key factors for the ecological divergence of the genera in the tribe Stipeae in Turkey.