Spatial pattern of Abies and Picea surface pollen distribution along the elevation gradient in the Qinghai-Tibetan Plateau and Xinjiang, China

In this study we examine the relationships between Abies and Picea abundance in surface pollen and sub-alpine coniferous forest (SCF) distribution, elevation and climate in the Qinghai-Tibetan Plateau using a large modern pollen data set consisting of 857 samples. Results indicate that Abies and Picea pollen are abundant in the southern and eastern Qinghai-Tibetan Plateau, where SCF dominates the landscape. Pollen percentages of both Abies and Picea show a unimodal pattern with changes in elevation and climate, and their optima occur at elevations from 2500 to 4000 m a.s.l., mean annual temperature from -1 to 10 degrees C and mean annual precipitation from 450 to 850 mm. The optimal elevation of Abies and Picea pollen distribution decreases with latitude from c. 4000 m in the south (21-32 degrees N) to c. 2500 m in the north (43-49 degrees N). The spatial pattern of Abies and Picea pollen abundance is highly correlated with the modern distribution of these taxa, which is largely controlled by elevation and climate. These relationships could provide a practical reference for interpretation of fossil pollen data in terms of climate and elevation in the Qinghai-Tibetan Plateau.