Linkage between C4 vegetation expansion and dune stabilization in the deserts of NE China during the late Quaternary

Knowledge of the role of C4 vegetation expansion in regulating dune stabilization during the late Quaternary is important for understanding the evolution of the environment and climate in the climatically-sensitive margin of the East Asian summer monsoon. However, due to the lack of both reliable vegetation records and chronological control during episodes of dune activity, the relationship between C4 vegetation expansion and dune stabilization in the deserts of NE China during the late Quaternary remains unclear. Here, we present a new regional compilation of late Quaternary stable carbon isotopic data from organic matter, together with dated records from sub-aerial sedimentary deposits in the region. Our compilation of vegetation development and dune activity in these deserts suggests that C4 vegetation expansion, with a main contribution from Chenopodiaceae, and a secondary contribution from Poaceae and Cyperaceae, may have played a critical role in dune semi-stabilization with a northwestward trend, from ∼13 to 9 ka; and dune stabilization throughout the entire study region, from ∼9 to 5 ka. In addition, during the late Holocene, intensified millet cultivation (or overgrazing) and/or climatic deterioration at ∼1.5 ka likely caused an increase in C4 vegetation abundance in the deserts of NE China, which is associated with a dune mobilization episode. In contrast, after ∼2.5 ka, decreased vegetation cover and dune mobilization in the Mu Us and Hobq deserts were likely caused by poor land-use practices and historically documented droughts. Overall, C4 vegetation expansion was the main cause of dune stabilization in these deserts during the late Quaternary.