Effects of a Surfactant Seed Coating on Alkali Bulrush Germination and Biomass

Abstract

Great Salt Lake (GSL) wetlands provide vital ecosystem services, including habitat for migratory birds. Alkali bulrush (Bolboschoenus maritimus) plays an important role in providing these services, but invasion by Phragmites australis has reduced the extent of alkali bulrush stands in GSL wetlands. Restoring alkali bulrush is a primary goal for GSL managers following Phragmites removal. However, rising temperatures and changing precipitation patterns with climate change, as well increasing human water demands upstream, may alter the hydropattern of GSL wetlands, thus lowering soil moisture availability and potentially inhibiting alkali bulrush germination and seedling establishment. Surfactant seed coatings have been effective in aiding the germination of seeds in upland restoration sites by reducing soil water repellency, but have not been tested in wetlands. We tested whether the addition of a surfactant seed coating to alkali bulrush seeds improved germination at four water levels in a greenhouse. Water level and seed coating were significantly associated with improved germination. In a second experiment, we tested the effect of the seed coating at a low and high dose and staggered water level drawdowns on seedling height and biomass over six weeks. Seed coating and time of water level drop were not significantly associated with differences in seedling height. The water level decrease may not have been extreme enough to negatively affect seedlings. More research is needed to determine if a surfactant seed coating enhances alkali bulrush germination and growth under less favorable water availability conditions.