Recolonization and Facilitation in Baltic Salt Marsh Vegetation

Abstract

Vegetation gaps are considered to be important for germination and establishment of species, which are weak competitors but have long-lived seeds in the soil. Vegetative growth is a colonization strategy especially important in regularly disturbed grasslands. In a salt marsh on the Baltic coast of Germany, we studied (i) the role of seedling recruitment and vegetative growth in recolonization of gaps, (ii) if gaps are necessary for seedling recruitment and (iii) whether gaps contribute to species diversity and composition of the salt marsh. We carried out a two-factorial field experiment during two years. We created 48 gaps of 0.04 m2 in size in autumn 2006. We eliminated the seed bank by sterilization and prevented vegetative growth into these gaps with dense meshes. We used a full-factorial design with four treatments: (1) seed bank and vegetative growth eliminated, (2) seed bank eliminated and vegetative growth intact, (3) seed bank intact and vegetative growth eliminated, (4) both intact. Seedlings an...