Sand dune species distribution and size variations in two areas inside a natural protected area subjected to different human disturbance

Sand dune species were analyzed across two areas included in the “Roman Coastal State Nature Reserve” (Italy): Ostia (O) and Marina di Palidoro (P). Significant variations in species distribution, dry mass and size over the gradient from the water-edge toward the inland between O and P were observed. Species colonize O, on an average, at 79 m from the water-edge extended along the gradient toward the inland over a length of 26 m. PD is 40.8 ± 9.9 plants·m−2. Ononis variegata and Elymus farctus have the highest PD (15.4 ± 1.3 plants·m−2), followed by Silene colorata and Sporobulus pungens (4.3 ± 3.9 plants·m−2), by Cakile maritima, Echinophora spinosa, Eryngium maritimum, Ammophila arenaria, Anthemis maritima, Cyperus capitatus, Medicago marina and Calystegia soldanella (