Abstract: The correspondence between topsoil pollen and modern vegetation is critical for reconstructing paleove-getation and paleoenvironment from palynological fossil records. Taking the Tianchi Lake watershed in the karst trough valley of eastern Sichuan Basin as a case, we explored the correspondence between pollen assemblages and current vegetation across seven land use types: cultivated land, abandoned cropland, shrublands, mixed forest, bamboo forest, pomelo orchard, and plum orchard. The results showed that the proportion of coniferous trees pollen was the highest (57.1%), followed by herbaceous plant pollen (25.7%), while that of fern spore was relatively low (22.8%), and broad-leaved tree pollen had the lowest proportion (17.2%). The proportion of broad-leaved tree pollen deviated from the typical subtropical evergreen broad-leaved forests. Such discrepancy might be attributed to the dilution effect of high-yield pollen on low-yield pollen and the inherent characteristics of the pollen. The topsoil pollen assemblages from different land use types showed a strong correspondence with the modern vegetation, particularly in terms of constructive and dominant species. The PCA results showed that pollen could distinguish the seven land use types. Among these, cultivated land and bamboo forests showed weaker correlations with Poaceae and Amaranthaceae, possibly due to soil disturbance from cultivation and the thick humus layer beneath bamboo forests. The representativeness of topsoil pollen varied across species or genera, with Pinus over-represented and deciduous Quercus and Poaceae under-represented. There were significant differences in average spore and pollen concentration among land use types, indicating that spore and pollen concentrations could reflect the intensity of human activities. The topsoil pollen assemblages in the Tianchi Lake watershed broadly reflected the overall characteristics of current vegetation. However, the interpretation of pollen assemblages required comprehensive consideration of various influencing factors, including soil erosion and palynological preservation conditions.

Key words: topsoil pollen, vegetation, pollen analysis, karst trough valley, Tianchi Lake watershed