Covariation in diaspore mass and dispersal patterns in three Mediterranean coastal dunes in southern Spain

摘要

The coastal dunes of southern Spain are an original Mediterranean ecosystem, insufficiently studied under dispersal. This study explores covariation patterns among diaspore mass, size, morphology, dispersal mode, and spatial dispersal in 78 native coastal dune species. Three coastal dunes under different climates were sampled and differentiated between fixed and mobile dunes. The Pérez-Harguindeguy methodology was applied and ANOVA, Kruskal-Wallis, and Mann-Whitney U tests were used in order to analyze the covariation. Diaspores were essentially small seeds or achenes (2-4 mm, from 10-5 to 1 g). The study revealed that diaspore mass is a key trait in the differentiation among dunes. Diaspore sizes vary between fixed and mobile dunes, and the smallest diaspores were overrepresented in Mediterranean-subdesert and in mobile dunes. The dispersal mode differed between the dunes and between fixed and mobile dunes. Anemochory was greater in Mediterranean-subdesert (50%) compared with Mediterranean-oceanic (8.5%) and Mediterranean-subtropical (9.5%) dunes and with mobile dunes (46.4%). Restricted dispersal is overrepresented in Mediterranean-oceanic dunes whereas developed spatial dispersal is in subdesert dunes. It has been shown how coastal dunes under variations in the Mediterranean climate could show differences of dispersal traits. Mobile dunes show dispersal patterns closer to those found in Mediterranean-subdesert dunes.