Modern Vegetation and Pollen Relationships in Four Southwestern Atlantic Coastal Lagoons

摘要

Pollen studies and their relationship with modern vegetation facilitate paleoecological reconstructions while changes in pollen abundance are indicators of environmental fluctuations. We analyzed the relationships between recent pollen deposits in the sediments of four Uruguayan coastal lagoons and catchment vegetation and analyzed the temporal dynamics of submerged aquatic vegetation (SAV). We mapped terrestrial vegetation, sampled SAV biomass, and analyzed the pollen record in each lagoon. The sediment samples represented the last 49–76 years of deposition, and most vegetation types were well represented in the pollen records. Pollen of Chenopodiaceae, proposed as indicators of saltmarshes, decreased in the surface samples of all lagoons, possibly due to the salinity reduction promoted by precipitation changes in the region. Pollen of SAV was found in all lagoons but with gaps in the record, and a submerged vegetated phase was recorded. Simultaneous botanical and pollen analyses better captured the large fluctuations of SAV in coastal lagoons.