Abstract: Based on the pollen spectrum of 58 topsoil samples collected in intermountain basin of the Middle Tianshan and a plantcommunity quadrat survey, we analyzed the relationship between topsoil pollen assemblages and modern vegetation distribution in this region. The results showed that: (1) The pollen assemblages were consistent with modern vegetation distribution. Based on the results of cluster analysis, the study area could be divided into five zones with increasing elevation, namely desert grassland, mountain grassland, mountain forest, subalpine meadow, and alpine scree vegetation. Axis 1 of the principal component analysis revealed that humidity was an important factor driving the formation of these vegetation zones. The pollen assemblages differed significantly among vegetation zones, with Chenopodiaceae Artemisia, ArtemisiaPoaceae Chenopodiaceae, PiceaArtemisiaPoaceaeChenopodiaceae (Picea>25%), CyperaceaeAlchemillaArtemisiaPoaceaeChenopodiaceae, and ArtemisiaChenopodiaceae CyperaceaeAlchemillaPoaceae pollen assemblages dominating the desert grassland, mountain grassland, mountain forest, subalpine meadow, and alpine scree vegetation zones, respectively. (2) Artemisia, Chenopodiaceae, Poaceae, Picea, Cyperaceae, and Alchemilla are the representative species in intermountainbasin of the Middle Tianshan, which can serve as important reference for palaeoenvironment reconstruction.Artemisia and Chenopodiaceae were over represented, while Poaceae was opposite. (3) The factors affecting the distribution and content of topsoil pollen in the vegetation zones were complex, with the pollen of Piceabeing greatly affected by the westerly circulation and those of Artemisia and Chenopodiaceae being significantly affected by human activities.

Key words: ecological protection, green manure in dryland conditions, crop diversity, green production, regionalization, pollen assemblage, vegetation zone, cluster analysis, principal component analysis.