Distribution of C4 plants in sand habitats of different climatic regions

Abstract

Sand dunes of warm regions provide suitable habitats for C4 plants because of their water and nitrogen use efficiency under high temperature and their high tolerance to ecological stress such as salinity, aridity and disturbance. We studied the distribution patterns of C4 plant species in five habitat types of sand dune ecosystems in three climatic regions (Mediterranean, Irano-Turanian and Hyrcanian). We compared the relative abundance of C4 plants in terms of richness and cover and aimed at identifying their habitat preferences in sand ecosystems. Our results revealed that C4 species notably contribute to the vegetation cover, despite their rather low contribution to the richness in comparison with C3 species. Generally, C4 plants were more prominent in mobile dunes, saltmarshes and disturbed sandy ground, but they showed regional differences in habitat preference. In northern and central Iran, C4 plants had the highest relative abundance in mobile dunes whereas in northeastern Greece they dominated disturbed sandy ground. The abundance of C4 plants appears to be influenced by climatic conditions. Central Iran, the driest and warmest among our study regions, has the highest proportion of C4 species in terms of number and cover. We observed an increasing trend in richness and cover of C4 plants with increasing aridity. As the number of C4 species alone may not fully reflect their role in a given area, the C4 plant total vegetation cover is shown to be an additional important parameter in ecological studies.