Effects of habitat nutrients and seed sources on growth and expansion of Typha domingensis

Abstract

Field reciprocal transplanting and outdoor tank experiments were conducted to determine the relative importance of habitat nutrients, particularly phosphorus (P), and seed sources on the growth and expansion of cattail ( Typha domingensis Pers.) in Everglades slough areas. Cattail plants originating from seeds collected at a P enriched site and two unenriched sites were reciprocally transplanted, and also planted in outdoor tanks. Significant site effects were found in the reciprocal transplanting experiment. After 7 months, plants (per genet) transplanted to the enriched site exhibited a greater biomass (dry weight) accumulation (152 versus 13 g), tissue nutrient concentrations, and proportional leaf biomass allocation than plants transplanted to the unenriched sites. Each original plant transplanted to the enriched site produced an average of 6.7 new ramets and covered approximately 1.2 m 2. However, no ramets were produced at unenriched sites. After 2.5 years, the total biomass for plants transplanted at unenriched sites was only about 6% of that of plants at the enriched site measured 2 years prior. While the field transplanting experiment highlighted the significance of site effects, the outdoor tank experiment demonstrated the importance of seed sources. The light saturated photosynthesis rates of plants from enriched and unenriched sites were 45.1, 19.9, and 17.0 μmol CO 2 m −2 s −1, respectively, and the relative growth rates were 26.9, 18.3, and 19.0 mg (dry weight) g −1 per day, respectively. This study provides evidence for the importance of P availability in species expansion in wetland ecosystems. Whether differences among cattail plants originating from different seed sources were phenotypic and/or genotypic needs to be further studied.