RECOVERY OF BRITTANY COASTAL MARSHES IN THE EIGHT YEARS FOLLOWING THE AMOCO CADIZ INCIDENT

Abstract

ABSTRACT The salt marshes on the Brittany coast of France have undergone a number of changes and have been influenced by man-made and natural factors since the Amoco Cadiz spill of March 1978. This work catalogs the ecological changes which have occurred over the past eight years and presents original data on the present state of these marshes. The recovery of Brittany coastal marshes began following cleanup operations which were often damaging to marsh and marsh substrate. The physical and toxicological properties of the oil also were damaging in the short term, especially to annual species. Natural recovery began primarily by invasion of exposed areas with annuals and rhizome spreading of perennials. Within four years, an almost logarithmic recruitment process was begun by annuals followed by perennials. Pioneer and opportunistic species increased, facilitated by partially vegetated substrates available for seed and seedling retention and by increased seed and rhizome production. Man-induced restoration was also important and was done largely by planting wild or cultured stock. The final stage of marsh recovery, as existing today, is the emergence of perennial species of high and low marsh at elevations and tidal exposures typical for their growth. These successional changes in a marsh following a major oil spill (and various other man-made impacts) provide an understanding of the complex processes involved in marsh recovery. This understanding allows the formulation of planning guidelines to predict the long-term impacts of future incidents and to make proper recommendations for cleanup and restoration to aid the recovery process.