Coastal dune vegetation and pollen representation in south Buenos Aires Province, Argentina

Abstract

Interpretation of Quaternary pollen assemblages can be improved by a better understanding of modern pollenvegetation relationships. Modern pollen deposition studies have shown that pollen assemblages reflect general patterns in the vegetation. However, pollen representation is biased by several factors, such as differences in pollen production, dispersal and preservation of taxa (Prentice, 1988). Thus, pollen abundance cannot be translated directly into plant abundance in the vegetation when interpreting pollen assemblages from the past. ABSTRACTAim To establish the relationship between coastal dune vegetation and its pollen representation as an aid to interpret Holocene vegetation dynamics and environmental changes from pollen assemblages.Location The study area is situated on the temperate Atlantic coast of south Buenos Aires Province, Argentina (c. 39°S and 61°20¢ W).Methods The vegetation of the active dune area adjacent to the beach was described on the basis of its floristic composition from 25 plots. Classification of the vegetation into distinct zones was carried out by cluster analysis. Surface samples were collected from each vegetation stand and analysed for their pollen composition. Pollen percentage data were analysed using principal components analysis in order to investigate the degree to which the different vegetation units can be distinguished by their pollen spectra. Pollen-vegetation relationships for selected taxa were explored using simple scatter plots and indices of association, under-and over-representation. Indices of floristic diversity and palynological richness were used to assess the representation of the vegetation in the pollen spectra.Results and conclusions Five vegetation zones are defined on the basis of species composition and their quantitative variation: back shore, mobile dunes, slacks, semi-fixed and fixed dunes. Pollen assemblages from back shore, mobile dunes and slacks are clearly differentiated from semi-fixed and fixed dunes. Pollen assemblages differ considerably from the associated vegetation composition. Major discrepancies are caused by large differences in pollen and vegetation proportion of Hyalis argentea and Discaria americana. There is a considerable proportion of non-local pollen in every spectrum. Pollen representation in the coastal dunes at Monte Hermoso is influenced by differences in pollen production, dispersal and preservation of individual taxa as well as by the spatial distribution of the vegetation, the topography of the dune system and the wind pattern. The pollen-vegetation relationship established in this study has important implication for understanding and interpreting fossil pollen records from coastal dune environments.

Vascular plants, coastal dunes between Pehuen-có and Monte Hermoso, Buenos Aires, Argentina

“…Among them, 10 were exotic taxa. The families Asteraceae, Poaceae and Fabaceae were the best represented, which agrees with previous studies (Fontana 2005). Agrostis platensis Adesmia filipes…”

“…Few studies have attempted to describe the floristic composition of Buenos Aires coastal dunes (e.g. Cabrera 1941;Faggi and Cagnoni 1991;Pfadenhauer 1993;Faggi et al 1997;Fontana 2005). In accordance to this, we present a species list of vascular plants recorded in an area of dune landscape of high conservation value and pristine characteristics, at southern Buenos Aires Atlantic coast.…”

Vegetation Impact on the Dune Stability and Formation on the Lithuanian Coast of the Baltic Sea

“…Ammophila arenaria and Leymus arenarius prefer dry and low-nutritious sandy soils, and tolerate saline sandy soils. Together with the Gypsophila paniculata and Lathyrus maritimus they form coastal sand dunes and stabilize sand drifting (Fontana 2005;Hilton, Konlechner 2011;Lucas, Carter 2013). Plants with their powerful root system make matts of various densities, well reinforcing the PBD and in this way reducing the sand transfer (Stankevičiūtė 2006;Olšauskas, Urbonienė 2009 …”

Coastal sand dune flora in the Thoothukudi District, Tamil Nadu, southern India

“…During the present study Poaceae, Malvaceae, Asteraceae, Euphorbiaceae, Cyperaceae were the most common families. Many authors have mentioned that in various parts of the world many dune ecosystems support high plant richness and diversity values (Musila et al 2001;Grootjans et al 2004;Fontana 2005;Celsi & Monserrat 2008). The present study also indicates that We also compared the floristic composition of the two coastal sites, Manapadu and Kulasakarapattanam.…”