Modern pollen and vegetation relationships in Mar Chiquita coastal lagoon area, southeastern Pampa grasslands, Argentina

Abstract

The relationships between vegetation and modern pollen are examined along a coast to inland gradient of plant communities in the Mar Chiquita coastal lagoon area, southeastern Pampa grasslands, Argentina. Local psammophytic, halophytic and freshwater plant communities that develop on coastal barriers, salt marshes and in shallow lakes respectively, were sampled for pollen analysis. The distribution of these communities can be related to specific environmental parameters such as topography, water table depth, substrate type and salinity. Samples were classified using Cluster Analysis and were ordinated using Detrended Correspondence Analysis (DCA). Results indicate that the plant communities sampled have distinct pollen assemblages: the psammophytic community is characterized by Poaceae, Cyperaceae and maximum values of psammophytic types; the halophytic community is characterized by maximum values of Chenopodiaceae ( Salicornia ambigua) and the freshwater community is characterized by maximum values of both Cyperaceae and hydrophytic types, and by Poaceae. Subsequently, fossil data from a core from Mar Chiquita coastal lagoon were compared to the modern data set in search of similarities between fossil and modern pollen spectra. A composite DCA revealed that the fossil pollen assemblages have modern counterparts, permitting to interpret the vegetation history of the area in greater detail than previously possible.