Climatic Changes and Vegetation Responses During Holocene Characteristic Period in the Northeastern Qinghai-Tibet Plateau.

The Qinghai-Tibet Plateau represents a highly sensitive region to global climate change. Understanding Holocene climate variations and vegetation responses in this area holds significant value for predicting future climate patterns, vegetation distribution changes, and biodiversity loss. Here, we aim to reconstruct Holocene climate conditions in the northeastern Qinghai-Tibet Plateau using modern and Holocene pollen records through weighted averaging-partial least squares (WA-PLS) analysis, and to examine the spatial-temporal relationship between vegetation dynamics and climate change during different characteristic periods. The results indicate that: (1) During the Holocene, the climate generally tended toward warmth and humidity with increased extremity. Based on temperature variations, it can be divided into ten characteristic periods. (2) The Holocene saw an increase in maximum temperature, average temperature, and precipitation, while minimum temperature decreased. (3) Forest decreased, undergoing three stages: expansion, contraction, and continuous contraction leading to stabilization. Grassland increased, following the stages of full expansion, localized expansion, and contraction with stabilization. (4) Under climatic influence, forest areas slightly expanded, while grassland areas slightly contracted. Meanwhile, land salinization intensified. We aim to enhance the understanding of climate change and vegetation evolution, providing a theoretical basis for addressing future climate change and biodiversity loss.