The role of sediment grain-size, mineralogy, and beach morphology on plant communities of two Mediterranean coastal dune systems

Abstract

Coastal dune ecosystems are characterized by a strong relationship between abiotic and biotic factors. The aim of the study is to identify the abiotic factors that mostly affect distribution and composition of plant dune communities along the coast-to-inland gradient, focusing the attention on sediment grain-size parameters, mineralogy, and dune morphology. The research was carried out on two coastal dune systems belonging to protected areas in the Mediterranean Basin, specifically in Northern and Southern Tuscany (Italy). Grain-size analysis, X-ray powder diffraction, topographic surveys, and floristic data recording were carried out along 11 transects perpendicular to the shoreline; the portion of the beach investigated is comprised within the foreshore and the backdune area. The analyses revealed some differences between the two coastal dune systems in terms of sediment parameters, mineralogy, and dune topography. The differences are mainly ascribed to the physical characteristics of the sites where the surveys were carried out. These data were matched with those provided by the vegetation sampling and then statistically processed by means of methods such as the Canonical Correlation Analysis (CCA), which showed that the mean grain-size is the most important abiotic factor that influences the composition of these coastal plant communities. These results might be considered to improve and optimize management and conservation programs for these ecosystems, since nowadays artificial dune reconstruction is a practice frequently used as a form of coastal protection

Assessment of the Restoration of the Remolar Dune System (Viladecans, Barcelona): The Resilience of a Coastal Dune System

“…In our case (Figure 7), it would be mainly due to the presence of Elymus farctus in the embryonic dune and of Medicago marina in the primary dune, two species with a large root volume. In addition to the relationship between dune morphology and vegetation, certain studies [49][50][51] have shown the relationship between grain size and plant zonation [52], in our case the textural differences between the crests of the embryonic and primary dunes contrast with the parts more internal to the dune system, due to the edaphic processes.…”

Integrating Different Databases to Offer a Geological Perspective of Coastal Management: A Review Case from the Northern Tuscany Littoral Cell (Italy)

“…The sand in the sector between the Magra River mouth and the convergence zone at Marina di Pietrasanta shows a mineralogical composition resemblance to the bedload supplied by the Magra River: quartz (40%), feldspar and mica (<40%), and carbonates (20%) [46,47]. To the south, the input from the Arno River prevails over any other stream in that sector of the coast: quartz (>50%), feldspar and mica (>25%), and carbonates (20%) [46,48]. The mean grain size is also an indication of sediment provenance.…”

Assessment of the Anthropogenic Sediment Budget of a Littoral Cell System (Northern Tuscany, Italy)

“…Similar to the northern sector, the grain-size tends to decrease approaching the convergence zone at Marina di Pietrasanta [51]. Sand composition analyses along this sector of the coast reported that quartz is the main component (>50%), along with feldspar and mica (>25%), and carbonates (20%) [48,57,58].…”