Water temperature controls the growth of waterhyacinth and South American sponge plant
John D. Madsen and Christy M. Morgan
Abstract
We examined the effect of water temperature on the growth of two free-floating aquatic species in this study: waterhyacinth [Eichhornia crassipes (Mart.) Solms] and sponge plant [Limnobium laevigatum (Humb. & Bonpl. Ex Willd.) Heine]. Waterhyacinth has been rated as the worst aquatic weed worldwide. A native of South and Central America, it is a recurring management issue in tropical and subtropical freshwater bodies in the United States. Sponge plant, native to southern Mexico, Central America, South America, and the Caribbean, was first detected in California in 2003. We studied the growth of these two species with two 6-wk growth studies (for each species), at water temperatures of 15, 20, 25, and 30 C. All temperatures were replicated in four tanks, for a total of 16 tanks. Waterhyacinth biomass was over 2,000 g dry weight (DW) m--2 for plants grown at 25 and 30 C by 42 d after start (DAS). Waterhyacinth density reached almost 800 rosettes m_2 at 42 DAS at 25 and 30 C. Waterhyacinth relative growth rate (RGR) reached 0.099 d--1, for a doubling time of 7.0 d. Sponge plant biomass at42 DAS was 400 g DW m--2 at 25 and 30 C. Density was as high as 3,900 rosettes m--2 at 42 DAS grown at 25 C. Sponge plant RGR was 0.12 d--1 at 25 C, for a doubling time of 5.7 d. The invasive potential of sponge plant has been demonstrated in this study.
Authors
- John D. Madsen, Research Biologist, USDA–ARS ISPHRU, Department of Plant Sciences, University of California, Davis (jmadsen@ucdavis.edu)
- Christy M. Morgan, Biological Research Technician, USDA–ARS ISPHRU, Department of Plant Sciences, University of California, Davis