Changes in vegetation type on the Chinese Loess Plateau since 75 ka related to East Asian Summer Monsoon variation

Abstract Floral communities in terrestrial habitats such as steppes are highly sensitive to regional climate changes. Here, we generated carbon and nitrogen isotope profiles for soil organic matter (SOM) in the Weinan loess-paleosol section in order to investigate changes in floral communities on the Chinese Loess Plateau (CLP) and their relationship to climate variation since 75 ka. δ 13 C SOM at Weinan ranges from −23.6 to −18.0‰ and δ 15 N SOM ranges from +3.4 to +5.5‰. Modeling based on the δ 13 C SOM record suggests that the proportion of C4 plants (%C4) has varied from lower during cold intervals (with minima of 24–32% at 73.1 ka, 20.9 ka (LGM), and 0.6 ka) to higher during warm intervals (with maxima of 62–64% at 53.0 ka and 8.2 ka). The δ 13 C SOM and δ 15 N SOM profiles are strongly correlated ( r  = +0.82; p(α) r  = +0.42; p(α) r  = +0.42; p(α) r  = +0.50; p(α)