| Although diverse, native-dominated plant communities are often desired in wetland restoration, little is known about plant succession in restored freshwater marshes. Research objectives were to determine (1) changes in plant communities and functional groups during succession in restored freshwater marshes, and (2) the role of seed bank, colonization, germination, and invasives in structuring succession.; Vegetation and seed bank communities of a 47-year restoration chronosequence showed successional change with three age classes: 5–10, 22–23, and 41–47 years after restoration. There was a long period before in-site seed production outweighed influences of off-site dispersal, implying that restored wetlands may be vulnerable to dramatic vegetation changes in response to disturbance. In another experiment, results indicate a small effect of initial differences in colonization, and show that colonization is rapid during early succession of restored marshes.; To determine the effect of soil successional changes on plant germination, ten species were tested across a water depth and simulated successional gradient. Seed moisture content and time of germination determined whether soil organic matter content affected germination. Hydrologic zone in which species were found in the field was a good indicator of germination hydrology, but successional status of mature plants bore little resemblance to germination performance on soils.; The importance of propagule dispersal and herbivory on continued dominance of the invasive grass, Phalaris arundinacea, was examined after a short-term disturbance. Disturbance, seeding and deer exclusion caused greater species richness than controls even three years after disturbance. P. arundinacea was unaffected by increased richness after the first year. Selective herbivory of species other than P. arundinacea aided in its continued dominance.; These results provide some encouragement in being able to direct and predict succession for the wetlands that are restored. The increasing dominance of emergent, invasive species in unmanaged succession seems to be a predictable pattern that can be modified through imposed disturbances and management of herbivores. Furthermore, increasing dominance of emergent species generally appears to be a predictable pattern in these wetlands. Finally, careful control of germination conditions in seeded restorations could favor establishment of certain species, making future management easier. |
