Effects of Nitrogen and Moisture Regimes on Arundinaria gigantea (Walt.) Muhl. Seedling Growth

1 Corresponding author: [email protected]; (901) 678-1502; fax: (901) 678-4746 ABSTRACT: A greater than 98% decline in Arundinaria gigantea (Walt.) Muhl. (giant cane or river cane) canebrake communities have resulted in a critically endangered ecosystem. Historical accounts suggest loss of canebrake habitat has resulted in the extirpation (and perhaps extinction) of many species. Thus, canebrake restoration is necessary for maintaining and enhancing biodiversity in the southeastern United States. The purpose of this study is to facilitate reestablishing A. gigantea canebrakes by optimizing growth and survivorship conditions for seedlings. To this end, we developed a lab experiment to test the effects of soil moisture (periodic drought, periodic flooding, and well-drained) and nitrogen fertilization on A. gigantea seedling growth and physiology. Arundinaria gigantea, while able to survive both drought and flooding, had significantly greater growth under well-drained conditions. Shoot growth averaged 28 cm and root growth averaged 11 cm in well-drained pots. Seedlings grown in flooded and drought treatments were not significantly different, averaging 20 cm in shoot growth and 4 cm in root growth. Biomass results mirrored shoot and root growth; biomass of roots and shoots was 30% greater under well-drained conditions. Nitrogen fertilization did not significantly affect seedling growth or physiology. Neither stomatal conductance nor net photosynthesis was significantly affected by moisture regime or nitrogen fertilization. However, results imply soil moisture regime as a significant factor controlling the growth and distribution of A. gigantea, and thus canebrake restoration will likely be most successful on well-drained soils.