Persistence of Coastal Vegetation in Supratidal Zones of Northern China

Abstract

Coastal vegetation comprises a number of coastal specialists and terrestrial generalists. It remains unclear how they persist on disturbed and undisturbed coastal conditions. We tested the hypothesis that coastal specialists may be superior to terrestrial generalists on supratidal zones of coasts, but their superiority can be influenced by human disturbances. Eight separate sandy coasts of the Shandong Peninsula were sampled, representing for disturbed and undisturbed sandy coasts. Plants growing on their supratidal zones were surveyed. On this basis, we compared the relative dominances, niche widths, and commonness of all species, and also analyzed species diversities of the coasts. Coastal specialists were found to be more common and widespread on supratidal zones of the sandy coasts than terrestrial generalists haphazardly invading from hinterlands. Coastal specialists exhibited lower Sørensen dissimilarities than terrestrial generalists among the coasts. Tourist trampling seemed more detrimental than pond fishery to coastal vegetation. Relative to terrestrial generalists, coastal specialists responded to human disturbances more deterministically, with steady decreases in species diversities. These evidences verify that coastal specialists are intrinsically superior to terrestrial generalists on supratidal zones of coasts, especially of undisturbed coasts, because their dispersal among coasts adapts well to local storm surge regime. They also validate that human disturbances can depress the superiority of coastal specialists, partly by inducing invasion of terrestrial generalists.

Natural persistence of the coastal plant Glehnia littoralis along temperate sandy coasts

“…This is a critical adaptation to seawater dispersal 33 38 39 . Supratidal zones are characterised by occasional seawater inundation 8 40 . Around the North Pacific Ocean, extreme storms often take place around winter to cause violent seawater surges 41 42 .…”

“…Many coastal species making up the vegetation are declining, and local or global extinction is ongoing 4 5 . They are irreplaceable stabilizers or maintainers of coastal ecosystems, and also rare resources to provide humans with herbal medicine, fibre and other necessities 6 7 8 . Glehnia littoralis that can be used as herbal medicine to treat lung diseases of humans is a typical species growing at temperate sandy coasts around the North Pacific Ocean 9 10 11 12 .…”