Restoration Affects Sexual Reproductive Capacity in a Salt Marsh

Plant sexual reproduction is an important driver of plant community maintenance, dispersal, and recovery from disturbance. Despite this, sexual reproduction in habitats dominated by clonally spreading perennial species, such as salt marshes, is often ignored. Communities dominated by long-lived perennial species can still depend on sexual reproduction for recolonizing large disturbed patches or for establishing in new patches, such as restored sites. We investigated the influence of restoration and elevation on flowering phenology, potential seed and seedling production, and insect flower damage of the dominant salt marsh grass, Spartina alterniflora, in reference and restored marshes in southeastern Louisiana, USA. We additionally tested whether elevation gradients or soil parameters could explain differences in sexual reproduction between sites. We demonstrate that sediment-slurry amendment restoration may not affect flowering phenology or insect flower damage at ecologically relevant levels, but that restoration activity increases sexual reproductive output at the patch scale. Restoration activity affected reproductive dynamics more often than changes in elevation alone. Restoration of subsiding salt marsh habitat by altering the soil environment may increase sexual reproductive capacity of these wetlands.