RESPONSE OF A TEXAS DISTICHLIS-SPICATA COASTAL MARSH FOLLOWING LESSERSNOW GOOSE HERBIVORY

Mudflat recolonization following lesser snow goose (LSG) (Anser caerul escens caerulescens (L.)) herbivory was investigated in a Texas Distic hlis spicata (L,) Greene (saltgrass) salt marsh. After 6 years of LSG herbivory, large mudflats were produced which contained small (2-4 m(2 )) islands of vegetation. Island perimeters, that were completely denu ded at initiation of this study, had lower vegetation cover and height compared to no use island centers after nearly 3 years of monitoring, even though no LSG use occurred during the evaluation period. Previou s level of LSG herbivory and physical disturbance along with summer dr ought and algal mat accumulations initially delayed the rate of revege tation. With improved hydroperiod, reduced salinity, decreased algal m at and rest from LSG impacts, lateral vegetative growth accelerated. M ean radial expansion was 128 cm after 2.5 years, No regeneration from seeds was observed. Competitive interference during recolonization occ urred between D. spicata and Salicornia virginica (L,) (Virginia glass wort), Frequent and severe LSG herbivory can result in unvegetated, er oding mudflats that may become permanent if followed by environmental conditions that retard vegetative recolonization. This may become an i ncreasingly important issue as LSG numbers increase and marsh area dec lines. (C) 1998 Elsevier Science B.V. All rights reserved