THE RESTORATION OF COASTAL SHINGLE VEGETATION - EFFECTS OF SUBSTRATE COMPOSITION ON THE ESTABLISHMENT OF SEEDLINGS

1. Shingle beach vegetation at Sizewell, Suffolk, UK, was extensively damaged by the construction of a power station. We investigated the fe asibility of restoring the vegetation by directly sowing seeds of spec ies important in the existing plant communities, in field and glasshou se experiments. The species sown were: Crambe maritima, Eryngium marit imum, Glaucium flavum, Lathyrus japonicus and Rumex crispus. 2. The fi eld experiment examined the effects of proximity to the sea, compositi on of the beach substrate, and its amendment with organic matter on se edling emergence and establishment. There was little emergence of seed lings during the first season and most occurred in the following sprin g, between February and April; G. flavum emergence was nearly confined to this period. A low percentage of the viable seeds of all five spec ies had emerged even after two seasons. Greatest emergence was in the monocarpic G. flavum, whereas the relatively long-lived perennials sho wed lower emergence and slower growth. Only G. flavum produced reprodu ctive plants, in the second year. 3. Seedling emergence was greater in organic matter treated plots for all species and most emerged better from sandy plots than shingle dominated plots. Although G. flavum emer gence was greater in sandy plots, seedling survivorship and growth wer e much greater in shingle plots; mortality showed evidence of density dependence. 4. A glasshouse experiment examined the effects of sowing density and substrate texture on the survival of G. flavum. On shingle , survival was negatively density-dependent, but the much lower surviv al on sand was density-independent. Consequently, the higher mortality on sandy field plots was probably directly associated with substrate effects. 5. Direct sowing of seeds on the beach cannot be recommended as a general technique for the restoration of shingle beach vegetation , except for annual or monocarpic species. Amendment with organic matt er provided little benefit that could not have been achieved more simp ly by the addition of beach sand to the coarsest shingle substrates.