Seed rain of restored and natural prairie wetlands

In prairie wetland restorations, seeds may be limiting plant recolonization but this has never been quantified in the field. We evaluated the seed rain in restored and natural wetlands to determine if seed limitation constrains plant recolonization. We were particularly interested in determining whether Carex species, dominant vegetation of seasonally flooded zones, are seed limited in restorations. We quantified seed rain over two years using seed traps and compared seed rain with on-site vegetation and seed banks. The seed rain, vegetation, and seed banks of restorations were dominated by annual species rather than the target non-invasive, native perennial vegetation. Invasive perennials were not dominant in the seed rain, vegetation, or seed banks of new restorations, despite the fact that they are abundant in many older restorations. The seed rain of natural wetlands was dominated by invasive perennials, which did not reflect the prevalence of native perennial vegetation onsite. Carex species were seed limited in both wetland types. Carex species need to be sown into prairie wetland restorations to overcome dispersal limitations and to pre-empt the perennial invasive species. In addition, landscape-scale perennial invasive species management is necessary to reduce the seed supply of undesirable species to all wetlands.