Germination,seedling occurrence and seedling survival of Spinifex sericeus R. Br. (Poaceae)

Abstract Spinifex sericeus is a clonal, perennial, dioecious, coastal foredune grass that is often used in beach rehabilitation programmes. The objectives of this study were to: (i) investigate the germination behaviour of S. sericeus; and (ii) examine the occurrence and survivorship of 5. sericeus seedlings in the dune systems on the mid-north coast of NSW. Diaspores and naked caryopses of S. sericeus require darkness for germination. Diaspore germination is adversely affected by leaching, probably due to the creation of anaerobic conditions around the caryopsis. Seedling emergence occurs mainly on the front of the foredune, as this is an area of active sand accretion and burial is necessary for germination. The presence of a hypocotyl allows germination and emergence from depths as great as 12.5 cm. In the two populations studied, seedling survival was low and probably made little contribution to population recruitment. The factors that appear to be responsible for the high mortality rate of seedlings are sand erosion, sand deposition and desiccation.