Relationship between surface pollen and their vegetation in Hupingshan National Nature Reserve, Hunan Province, China

Hupingshan National Nature Reserve, located in Hunan Province, South Central China, is characterized by rich biodiversity, complex floral composition, pronounced human perturbation, dominant secondary vegetation, low dominance of constructive species, and complex and diverse pollen assemblage characteristics. We explored the relationship between surface pollen assemblages and vegetation characteristics using 34 samples. The results showed that arboreal pollen accounted for 84.4% of the total. The AP/NAP (AP: arboreal pollen, NAP: nonarboreal pollen) ratio was roughly 5.4. The pollen concentration was 149157 grains·g^-1. Evergreen broadleaved pollen assemblages did not reflect the local vegetational community. Pollen assemblages of deciduous broadleaf forest were partly consistent with plant community composition. Deciduous-evergreen broadleaf mixed forest, shrub-meadow and corn field pollen assemblages corresponded well with their local vegetational community. Local dominant species and constructive species abundances were well represented in pollen assemblages. Castanopsis/Lithocarpus, Fagus, Toxicodendron, Carpinus/Corylus, Ericaceae, and Symplocos were under-represented, whereas Pinus, Betula and Cyclobalanopsis were over-represented pollen taxa. Based on cluster analysis and detrended correspondence analysis (DCA), the shrub-meadow, evergreen broadleaf forest and deciduous broadleaf forest could be well distinguished by pollen spectra, except deciduous-evergreen broadleaf mixed forest, or evergreen broadleaved forest and deciduous broadleaved forest. The significant discrepancy in consistency between pollen assemblages and vegetation community was chiefly impacted by pollen representativeness, vegetation patchy characteristics, topography, local climate, and human activities.