Some edaphic and meteorological conditions were examined to detect environmental gradients from shoreline to inland at the Kado-ori coast, Ibaraki, Japan in 1989. At the same coast, zonal distribution patterns of coastal dune plant species including three ubiquitous perennials, Calystegia soldanella, Carex kobomugi and Ischaemum anthephoroides, were described, relating to the environmental gradients. Environmental gradients were found in water availability, evaporative demand, and soil-water salinity. Water availability evaluated by thickness of capillary water layer increased from 10 cm at 20 m to 48 cm at 85 m from the shoreline, reflecting the percentage of fine sand. Evaporative demand, which was evaluated by the evaporation rate from a wet black filter paper, decreased with increasing distance from the shoreline. Soil-water salinity was lowest (15 mM) at 85 m from the shoreline and highest (90 mM) at 30 m. On the coast, Calystegia soldanella, a salt-tolerant perennial, was distributed mainly on harsh area from 40 to 60 m from the shoreline. On the other hand, Ischaemum anthephoroides and Carex kobomugi, less salt-tolerant perennials, occurred mainly in the range from 70 to 80 m from the shoreline where environmental conditions were somewhat hospitable.

Key words: coastal dune plants; evaporative demand; soil-water salinity; water availability; zonal plant distribution.