No abstract

Vegetation establishment proceeded rapidly on islands in Atchafalaya Bay, Louisiana, following subaerial exposure in lg73. By 1980, ll km z of land were vegetated, with four primary plant associations dominating the plant assemblage: Sagittaria latifolia on intertidal elevations, Salix nigra on higher elevations at the heads of islands, Typha latifolia at elevations between the S. nigra and the S. latifolia, and a transitional community at intermediate elevations composed of the above plants with Cyperus difformis~ Eleocharis spp., Ammania coccinea, and Sphenoclea ze[landica. Colonization by the furbearers nutria (Myocastor Coypus) and muskrat (Ondatra zibethicus) has also been rapid on the islands. A preliminary exclosure study over a two-year period (1980-81) documented significantly higher plant biomass for S. latifolia and A. eoccinea within exclosed plots than in control plots, and there was some indication that plant species composition was affected by herbivory.Long-term exelosure studies and concurrent population studies of herbivores are recommended.