Quantitative analysis of pollen and vegetation richness relationship at the southeastern Buenos Aires coastal dune system

CAROLINA VASQUEZ; SOTTILE, GONZALO; SILVINA STUTZ

Bariloche

Congreso; IAL IPA 2022 Lagos Memorias del Territorio; 2022

IAL/IPA

This project aims to evaluate the relationship between plant and pollen richness of the CoastalDune System (CDS) of the southeastern Buenos Aires, Argentina, associated to taxonomicand taphonomic constraints on pollen production, preservation and dispersion at local andlandscape scales. Pollen analysis is a widely used tool in paleoecology to reconstruct bothvegetation history and to analye temporal changes in plant diversity. However, pollenabundance cannot be directly translated into plant abundance in the vegetation wheninterpreting past pollen assemblages. To overcome this issue, it is necessary to improvepast plant diversity reconstructions by calibrating modern pollen-vegetation diversityrelationships, by studying pollen surface samples to understand fossil pollen assemblagesand their ecological signi7cance. We took 21 pollen surface samples from interdune lagoonsto analye their pollen content and its relationship with the surrounding vegetation cover atdi;erent radii (5, 10, 20, 1000, 2000 m). Sediment samples were treated according to standardtechniques to obtain pollen grains. Vegetation cover was calculated by 7eld measurementsat 5, 10 and 20 m. We took local vegetation information to generate vegetation maps at1000 and 2000 m radii from the pollen surface samples point. Plant richness and pollensurface samples were analyed through linear regression models and multivariate analysis.We 7nd positive and close correlation between plant richness and their pollen equivalents(adjusted r2= 0.5116). Also, we 7nd a positive and signi7cant correlation between pollensurface sample richness and plant richness at 20, 1000 and 2000 m. Multivariate analysisrelates high pollen surface sample richness with sites partially covered by Pinus and otheralien tree and herbs communities, within to 2 km radii. These preliminary results showsquantitatively that there is a positive relationship between plant and pollen richness at local(20 m), extra-local (landscape) and regional scales in the CDS. However, the AdjustedR-squared is smaller at 2 km distance with respect to 20 m. This patter suggest that thesemodels 7t better assuming smaller Relevant Pollen Source Area.