Modern pollen and its relationship with vegetation and climate in the Mu Us Desert and surrounding area, northern China: Implications of palaeoclimatic and palaeocological reconstruction

Abstract This study establishes the spatial and quantitative relationship between modern pollen, vegetation and climate based on 84 surface pollen samples from a nature reserve and ecological restoration area in the Mu Us Desert and surrounding areas, including seven natural vegetation types. Pollen spectra, discriminant analysis and spatial distribution patterns of the main pollen types are used to explore the relationship between pollen assemblages and vegetation types. Results show that each vegetation type can be characterized by a distinct modern pollen assemblage as follows: (1) coniferous forest: Pinus Diploxylon-type and Picea; (2) deciduous forest: Pinus Diploxylon-type, Quercus, Artemisia and Poaceae; (3) deciduous shrub: Pinus Diploxylon-type, Artemisia and Poaceae; (4) grass meadow: Poaceae and Cyperaceae; (5) grass steppe: Poaceae and Artemisia; (6) desert steppe: Chenopodiaceae, Artemisia and Poaceae; and (7) desert: Chenopodiaceae, Nitraria and Artemisia. The higher percentage and lower concentration of Pinus pollen in the Mu Us Desert can be explained by effective long-distance transport from the mountain forest, while Picea has a limited pollen dispersal ability via wind-borne dispersal. Poaceae pollen is well represented and has a higher percentage in several different types of ecological conditions. Modern pollen–climate relationships are assessed using redundancy analysis and weighted averaging partial least squares regression. Significant relationships exist between pollen assemblages and mean annual temperature (R2 = 0.67; RMSEP 1.7 °C; max. bias 2.5 °C), July precipitation (R2 = 0.58; RMSEP 17.8 mm; max. bias 26.0 mm), and January precipitation (R2 = 0.82; RMSEP 0.9 mm; max. bias 1.8 mm). Furthermore, the climate variables obtained by spatial interpolation of data from meteorological stations are used to cross-check the data reconstructed by pollen-climate transfer functions. Our work provides a more comprehensive understanding of the qualitative and quantitative relationships between modern pollen and vegetation/climate and serves as a basis for the paleovegetation and paleoclimate reconstruction in arid and semiarid regions of northern China and similar areas.