Sand Accretion and Salinity as Constraints on the Establishment of Leymus arenarius for Land Reclamation in Iceland

Seed harvested from wild populations ofLeymus arenarius is sownextensively in Iceland to stabilize sandy barrens, on the coastand inland. Sand accretion can reach 50 cm over 3 months insummer near the outwash of glacial rivers on the south coastof Iceland and thus may be an important factor influencing survivaland growth ofL. arenarius . Newly germinated seedlings had great potential for elongationin darkness (etiolation). The length of the longest etiolatedleaf increased significantly with seed mass. The etiolationresponse proved to be a good predictor of their ability to emergefrom burial with sand. The mean length of etiolated shoots wasapprox. 16 cm and 40% of seedlings emerged when germinatingseeds were buried with 15 cm of sand, whereas none emerged fromburial under 20 cm of sand. A moderately high and sustainedrate of sand deposition (2–4 cm week^-1), applied to 10-weekold seedlings in a glasshouse experiment, significantly increasedleaf length and the allocation of biomass to shoots, such thatoverall biomass was slightly but not significantly increased. The growth responses of seedlings of one coastal populationand two inland populations ofLeymus arenarius were comparedwhen challenged with salinities ranging from 0 to 600 mM NaClin sand culture. The numbers of tillers produced by the coastalpopulation was stimulated by salinity in the range 200–400mM NaCl, unlike their inland counterparts. The total dry massof the coastal population was less adversely affected by highsalinity than that of the two inland populations, mainly becauseroot biomass was reduced less; total leaf area was also slightlyless reduced in the coastal population. The reclamation of sandbarrens in Iceland with high accretion rates would benefit fromsowing seeds from larger-seeded populations, at a depth of 5–10cm; at coastal reclamation sites, it would be preferable touse seed from the more salt-tolerant coastal populations. Leymus arenarius ; lyme grass; sand accretion; etiolation; seedling emergence; seed mass; salt tolerance; revegetation