Phenology of Curlyleaf Pondweed (Potamogeton Crispus) in the Southeastern U. S.

Turnage, G., & Madsen, J. D. (2013). Phenology of Curlyleaf Pondweed (Potamogeton Crispus) in the Southeastern U. S. Aquatic Plant Management Society 53rd Annual Meeting. San Antonio, TX.

Abstract

Curlyleaf pondweed (Potamogeton crispus) is a submersed aquatic plant that is native to Europe, Asia, Africa, and Australia. It first appeared in the United States in the 1840’s and has since been distributed throughout the lower 48 states. Curlyleaf pondweed spread across the southeastern parts of the U. S. in the 1940’s and 50’s. Long distance dispersal is thought to occur mainly through fish hatchery activities and in many states the first observance of curly leaf pondweed was in hatchery ponds. Curlyleaf pondweed is capable of outcompeting native species and forming large monospecific beds. Curlyleaf pondweed primarily reproduces vegetatively via turion production or rhizome elongation. Turions, vegetative structures capable of surviving extreme conditions (i.e. drought, freezing, herbicide treatments) and producing a viable plant capable of reproduction, are typically produced in the weeks before the plant senesces. In northern populations, curlyleaf pondweed has an atypical growth cycle in that it senesces in early summer, is dormant through the summer, and turions sprout in mid to late fall, and produce turions in the spring. Our study was conducted to better understand the phenology of curlyleaf pondweed in the southern U. S. because so little is known about these populations. In our study, plant height peaked in July at 68 cm. This coincided with maximum annual water temperatures of 30C (86F). Total biomass peaked in August 2012 and January 2013. However, plant growth occurred in all months. Turion, aboveground (minus turions), and belowground plant structures made up 19 %, 44 %, and 37 % of total plant biomass respectively. On average, plants yielded 39 turions per individual or 2,140 turions per square meter of substrate. It appears that plant growth and turion production occur year round suggesting that southern populations of curlyleaf pondweed have altered their phenology to climatic conditions present in the southeastern U. S.