Pollen rain–vegetation relationship along an elevational gradient in the Serra dos Órgãos National Park, southeastern Brazil

International audienceWe analyzed modern pollen deposition along an altitudinal gradient in the Brazilian southeastern coastal mountains between 1600 and 2200 m elevation in order to investigate the relationship between modern vegetation and pollen rain, within vegetation composed of montane and upper montane forest in a mosaic with campos de altitude (CDA). The results revealed that the CDA pollen assemblage represents a much larger source area than the forest pollen assemblage, which is comprised of more local taxa. Anemophilous pollen from vegetation at lower elevations is overrepresented in the higher elevation pollen traps. Although arboreal taxa dominate the pollen assemblages-even in the grassland pollen traps-the composition of the pollen traps can be confidently related to the vegetation surrounding the collection site. To improve distinction between grassland and forest dominance in a complex environmental mosaic subject to temporal dynamism, we selected a suite of arboreal pollen taxa aiming to reduce the influence of over-and underrepresentation of some pollen taxa in such kind of environment. Our findings permit more robust interpretation of palaeo-ecological and-geographical relationships between forest and CDA and build a firmer foundation for understanding how future climatic change may impact montane vegetation in SE Brazil