Establishment and Seedling Growth of Sawgrass and Cattail from the Everglades

The objectives of this study were to test the effects of water level and nutrient availability on the reproductive output, germination, and early growth of sawgrass and cattail. Ultimately, this information would enhance our ability to regenerate sawgrass in the Everglades, and possibly to reduce cattail recruitment. It has been shown for other species that various characteristics of the environment in which a plant is growing can affect its reproductive output. Differences in seed production among plants from the enriched and unenriched areas of the Everglades would affect the ability of those plants to reproduce themselves and to spread to new areas.

The main germination experiment was designed to test the effects of water level and nutrient availability on the germination of sawgrass and cattail seeds collected from both enriched and unenriched areas. Two smaller experiments supplemented this study. The first of these experiments tested the effects of chilling, a potential dormancy breaker, on sawgrass germination. The second explored the role of light in stimulating the germination of both species. All germination studies were conducted in the Duke University Greenhouse. Chilling was tested on these two species because chilling is an important dormancy-breaking factor in many species. The Everglades is subtropical, so little if any effect was expected. Cattail has been found to germinate best in high light conditions, but the effects of light on sawgrass are unknown. A study of the growth of sawgrass and cattail seedlings was set up in an attempt to identify the age at which the faster potential growth rate of cattail overcame the initial advantage given to sawgrass by its larger seed size.