A Simulation Model for Growth of the Submersed Aquatic Macrophyte Eurasian Watermilfoil (Myriophyllum Spicatum L.)
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENGINEER RESEARCH AND DEVELOPMENT CENTER
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A simulation model for biomass dynamics of the submersed macrophyte Myriophyllum spicatum is presented. The model MILFO is based on carbon flow through the vegetation in meter-squared cu m water columns. It includes descriptions of several factors that affect biomass dynamics, such as site-characteristic changes in climate, water temperature, water transparency, pH and oxygen effects on CO2 assimilation rate at light saturation, wintering strategies, grazing and mechanical control removal of shoot biomass, and of latitude. The characteristics of the community and of the site can be easily modified by the user. MILFO incorporates insights into the processes affecting the dynamics of an Eurasian watermilfoil community in relatively shallow, hard water 0.5-6 m depth DIC concentration 0.8 mmol and pH ranging from 7.6 to 9.4 under ample supply of nitrogen and phosphorus in a pest-, disease-, and competitor-free environment under the prevailing weather conditions. It has been calibrated on data pertaining to a milfoil community in Lake Wingra, Wisconsin, USA. At that site, growth starts from the basal rhizomeroot crown system, alone or with wintering shoot biomass present. Shoot biomass usually peaks twice a year, in June originating from the first plant cohort and in August from the second cohort, and intensive downward transport of soluble carbohydrates occurs after anthesis of each cohort, replenishing the rhizomeroot crown system. In a tropical climate, a third plant cohort is active. MILFO simulated the dynamics of plant and rhizomeroot crown biomass at Lake Wingra well over a period of 1 to 5 years. It has been used to calculate plant and rhizomeroot crown biomass for the same latitude in a different year and for other latitudes in temperature Alabama, USA and tropical India areas, where it simulated biomass ranges similar to those measured in the field.
- Biological Oceanography