The Impact of Sea Water Immersion on the Viability of Psammophilous Species Leymus racemosus subsp. sabulosus and Ammophila arenaria

Abstract

Leymus racemosus (Lam.) Tzvelev subsp. sabulosus (M. Bieb.) Tzvelev (mammoth wildrye) and Ammophila arenaria (L.) Link (marram grass) are perennial, psammophilous species which dominate sand dunes due to their biological characteristics. Their communities have an important role in the formation of the natural vegetation cover of coastal sand strips along the Bulgarian Black Sea Coast. This study provides the first systematic analysis of tolerance of L. racemosus subsp. sabulosus and A. arenaria to sea water immersion along the Bulgarian Black Sea Coast. It aims to determine effects of flooding stress on whole plants and how long rhizomes can remain viable in sea water. Two experiments establish that decomposition of leaves of immersed plants starts from the 7th day. A growth of stems and root sprouts is observed on the same day. There are no visible decompositions of stems, roots and rhizomes till the end of the experiment (20th day). Rhizomes from the investigated species are able to regenerate after 30 days of submergence and bud viability appears to be enhanced slightly by sea water. L. racemosus subsp. sabulosus shows higher bud viability than A. arenaria. The possible negative consequences of flooding to L. racemosus and A. arenaria communities based on experimental results, hydrodynamical modelling, detailed topography, bathymetry surveys and detailed GIS mapping on Panorama Beach are discussed.